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2020-09-06Merge tag 'for-linus-5.9-rc4-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen updates from Juergen Gross: "A small series for fixing a problem with Xen PVH guests when running as backends (e.g. as dom0). Mapping other guests' memory is now working via ZONE_DEVICE, thus not requiring to abuse the memory hotplug functionality for that purpose" * tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: add helpers to allocate unpopulated memory memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC xen/balloon: add header guard
2020-09-05Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge misc fixes from Andrew Morton: "19 patches. Subsystems affected by this patch series: MAINTAINERS, ipc, fork, checkpatch, lib, and mm (memcg, slub, pagemap, madvise, migration, hugetlb)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: include/linux/log2.h: add missing () around n in roundup_pow_of_two() mm/khugepaged.c: fix khugepaged's request size in collapse_file mm/hugetlb: fix a race between hugetlb sysctl handlers mm/hugetlb: try preferred node first when alloc gigantic page from cma mm/migrate: preserve soft dirty in remove_migration_pte() mm/migrate: remove unnecessary is_zone_device_page() check mm/rmap: fixup copying of soft dirty and uffd ptes mm/migrate: fixup setting UFFD_WP flag mm: madvise: fix vma user-after-free checkpatch: fix the usage of capture group ( ... ) fork: adjust sysctl_max_threads definition to match prototype ipc: adjust proc_ipc_sem_dointvec definition to match prototype mm: track page table modifications in __apply_to_page_range() MAINTAINERS: IA64: mark Status as Odd Fixes only MAINTAINERS: add LLVM maintainers MAINTAINERS: update Cavium/Marvell entries mm: slub: fix conversion of freelist_corrupted() mm: memcg: fix memcg reclaim soft lockup memcg: fix use-after-free in uncharge_batch
2020-09-05mm/khugepaged.c: fix khugepaged's request size in collapse_fileDavid Howells
collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to be read to page_cache_sync_readahead(). The intent was probably to read a single page. Fix it to use the number of pages to the end of the window instead. Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Yang Shi <shy828301@gmail.com> Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Eric Biggers <ebiggers@google.com> Link: https://lkml.kernel.org/r/20200903140844.14194-2-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm/hugetlb: fix a race between hugetlb sysctl handlersMuchun Song
There is a race between the assignment of `table->data` and write value to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on the other thread. CPU0: CPU1: proc_sys_write hugetlb_sysctl_handler proc_sys_call_handler hugetlb_sysctl_handler_common hugetlb_sysctl_handler table->data = &tmp; hugetlb_sysctl_handler_common table->data = &tmp; proc_doulongvec_minmax do_proc_doulongvec_minmax sysctl_head_finish __do_proc_doulongvec_minmax unuse_table i = table->data; *i = val; // corrupt CPU1's stack Fix this by duplicating the `table`, and only update the duplicate of it. And introduce a helper of proc_hugetlb_doulongvec_minmax() to simplify the code. The following oops was seen: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page Code: Bad RIP value. ... Call Trace: ? set_max_huge_pages+0x3da/0x4f0 ? alloc_pool_huge_page+0x150/0x150 ? proc_doulongvec_minmax+0x46/0x60 ? hugetlb_sysctl_handler_common+0x1c7/0x200 ? nr_hugepages_store+0x20/0x20 ? copy_fd_bitmaps+0x170/0x170 ? hugetlb_sysctl_handler+0x1e/0x20 ? proc_sys_call_handler+0x2f1/0x300 ? unregister_sysctl_table+0xb0/0xb0 ? __fd_install+0x78/0x100 ? proc_sys_write+0x14/0x20 ? __vfs_write+0x4d/0x90 ? vfs_write+0xef/0x240 ? ksys_write+0xc0/0x160 ? __ia32_sys_read+0x50/0x50 ? __close_fd+0x129/0x150 ? __x64_sys_write+0x43/0x50 ? do_syscall_64+0x6c/0x200 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: e5ff215941d5 ("hugetlb: multiple hstates for multiple page sizes") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm/hugetlb: try preferred node first when alloc gigantic page from cmaLi Xinhai
Since commit cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma"), the gigantic page would be allocated from node which is not the preferred node, although there are pages available from that node. The reason is that the nid parameter has been ignored in alloc_gigantic_page(). Besides, the __GFP_THISNODE also need be checked if user required to alloc only from the preferred node. After this patch, the preferred node is tried first before other allowed nodes, and don't try to allocate from other nodes if __GFP_THISNODE is specified. If user don't specify the preferred node, the current node will be used as preferred node, which makes sure consistent behavior of allocating gigantic and non-gigantic hugetlb page. Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma") Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <guro@fb.com> Link: https://lkml.kernel.org/r/20200902025016.697260-1-lixinhai.lxh@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm/migrate: preserve soft dirty in remove_migration_pte()Ralph Campbell
The code to remove a migration PTE and replace it with a device private PTE was not copying the soft dirty bit from the migration entry. This could lead to page contents not being marked dirty when faulting the page back from device private memory. Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Link: https://lkml.kernel.org/r/20200831212222.22409-3-rcampbell@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm/migrate: remove unnecessary is_zone_device_page() checkRalph Campbell
Patch series "mm/migrate: preserve soft dirty in remove_migration_pte()". I happened to notice this from code inspection after seeing Alistair Popple's patch ("mm/rmap: Fixup copying of soft dirty and uffd ptes"). This patch (of 2): The check for is_zone_device_page() and is_device_private_page() is unnecessary since the latter is sufficient to determine if the page is a device private page. Simplify the code for easier reading. Signed-off-by: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Link: https://lkml.kernel.org/r/20200831212222.22409-1-rcampbell@nvidia.com Link: https://lkml.kernel.org/r/20200831212222.22409-2-rcampbell@nvidia.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm/rmap: fixup copying of soft dirty and uffd ptesAlistair Popple
During memory migration a pte is temporarily replaced with a migration swap pte. Some pte bits from the existing mapping such as the soft-dirty and uffd write-protect bits are preserved by copying these to the temporary migration swap pte. However these bits are not stored at the same location for swap and non-swap ptes. Therefore testing these bits requires using the appropriate helper function for the given pte type. Unfortunately several code locations were found where the wrong helper function is being used to test soft_dirty and uffd_wp bits which leads to them getting incorrectly set or cleared during page-migration. Fix these by using the correct tests based on pte type. Fixes: a5430dda8a3a ("mm/migrate: support un-addressable ZONE_DEVICE page in migration") Fixes: 8c3328f1f36a ("mm/migrate: migrate_vma() unmap page from vma while collecting pages") Fixes: f45ec5ff16a7 ("userfaultfd: wp: support swap and page migration") Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Alistair Popple <alistair@popple.id.au> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.au Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm/migrate: fixup setting UFFD_WP flagAlistair Popple
Commit f45ec5ff16a75 ("userfaultfd: wp: support swap and page migration") introduced support for tracking the uffd wp bit during page migration. However the non-swap PTE variant was used to set the flag for zone device private pages which are a type of swap page. This leads to corruption of the swap offset if the original PTE has the uffd_wp flag set. Fixes: f45ec5ff16a75 ("userfaultfd: wp: support swap and page migration") Signed-off-by: Alistair Popple <alistair@popple.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Peter Xu <peterx@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@popple.id.au Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm: madvise: fix vma user-after-freeYang Shi
The syzbot reported the below use-after-free: BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline] BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline] BUG: KASAN: use-after-free in do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 Read of size 8 at addr ffff8880a6163eb0 by task syz-executor.0/9996 CPU: 0 PID: 9996 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 madvise_willneed mm/madvise.c:293 [inline] madvise_vma mm/madvise.c:942 [inline] do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 do_madvise mm/madvise.c:1169 [inline] __do_sys_madvise mm/madvise.c:1171 [inline] __se_sys_madvise mm/madvise.c:1169 [inline] __x64_sys_madvise+0xd9/0x110 mm/madvise.c:1169 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Allocated by task 9992: kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482 vm_area_alloc+0x1c/0x110 kernel/fork.c:347 mmap_region+0x8e5/0x1780 mm/mmap.c:1743 do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 vm_mmap_pgoff+0x195/0x200 mm/util.c:506 ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 9992: kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693 remove_vma+0x132/0x170 mm/mmap.c:184 remove_vma_list mm/mmap.c:2613 [inline] __do_munmap+0x743/0x1170 mm/mmap.c:2869 do_munmap mm/mmap.c:2877 [inline] mmap_region+0x257/0x1780 mm/mmap.c:1716 do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 vm_mmap_pgoff+0x195/0x200 mm/util.c:506 ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 It is because vma is accessed after releasing mmap_lock, but someone else acquired the mmap_lock and the vma is gone. Releasing mmap_lock after accessing vma should fix the problem. Fixes: 692fe62433d4c ("mm: Handle MADV_WILLNEED through vfs_fadvise()") Reported-by: syzbot+b90df26038d1d5d85c97@syzkaller.appspotmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: <stable@vger.kernel.org> [5.4+] Link: https://lkml.kernel.org/r/20200816141204.162624-1-shy828301@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm: track page table modifications in __apply_to_page_range()Joerg Roedel
__apply_to_page_range() is also used to change and/or allocate page-table pages in the vmalloc area of the address space. Make sure these changes get synchronized to other page-tables in the system by calling arch_sync_kernel_mappings() when necessary. The impact appears limited to x86-32, where apply_to_page_range may miss updating the PMD. That leads to explosions in drivers like BUG: unable to handle page fault for address: fe036000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pde = 00000000 Oops: 0002 [#1] SMP CPU: 3 PID: 1300 Comm: gem_concurrent_ Not tainted 5.9.0-rc1+ #16 Hardware name: /NUC6i3SYB, BIOS SYSKLi35.86A.0024.2015.1027.2142 10/27/2015 EIP: __execlists_context_alloc+0x132/0x2d0 [i915] Code: 31 d2 89 f0 e8 2f 55 02 00 89 45 e8 3d 00 f0 ff ff 0f 87 11 01 00 00 8b 4d e8 03 4b 30 b8 5a 5a 5a 5a ba 01 00 00 00 8d 79 04 <c7> 01 5a 5a 5a 5a c7 81 fc 0f 00 00 5a 5a 5a 5a 83 e7 fc 29 f9 81 EAX: 5a5a5a5a EBX: f60ca000 ECX: fe036000 EDX: 00000001 ESI: f43b7340 EDI: fe036004 EBP: f6389cb8 ESP: f6389c9c DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010286 CR0: 80050033 CR2: fe036000 CR3: 2d361000 CR4: 001506d0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: fffe0ff0 DR7: 00000400 Call Trace: execlists_context_alloc+0x10/0x20 [i915] intel_context_alloc_state+0x3f/0x70 [i915] __intel_context_do_pin+0x117/0x170 [i915] i915_gem_do_execbuffer+0xcc7/0x2500 [i915] i915_gem_execbuffer2_ioctl+0xcd/0x1f0 [i915] drm_ioctl_kernel+0x8f/0xd0 drm_ioctl+0x223/0x3d0 __ia32_sys_ioctl+0x1ab/0x760 __do_fast_syscall_32+0x3f/0x70 do_fast_syscall_32+0x29/0x60 do_SYSENTER_32+0x15/0x20 entry_SYSENTER_32+0x9f/0xf2 EIP: 0xb7f28559 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90 8d 76 EAX: ffffffda EBX: 00000005 ECX: c0406469 EDX: bf95556c ESI: b7e68000 EDI: c0406469 EBP: 00000005 ESP: bf9554d8 DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000296 Modules linked in: i915 x86_pkg_temp_thermal intel_powerclamp crc32_pclmul crc32c_intel intel_cstate intel_uncore intel_gtt drm_kms_helper intel_pch_thermal video button autofs4 i2c_i801 i2c_smbus fan CR2: 00000000fe036000 It looks like kasan, xen and i915 are vulnerable. Actual impact is "on thinkpad X60 in 5.9-rc1, screen starts blinking after 30-or-so minutes, and machine is unusable" [sfr@canb.auug.org.au: ARCH_PAGE_TABLE_SYNC_MASK needs vmalloc.h] Link: https://lkml.kernel.org/r/20200825172508.16800a4f@canb.auug.org.au [chris@chris-wilson.co.uk: changelog addition] [pavel@ucw.cz: changelog addition] Fixes: 2ba3e6947aed ("mm/vmalloc: track which page-table levels were modified") Fixes: 86cf69f1d893 ("x86/mm/32: implement arch_sync_kernel_mappings()") Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Chris Wilson <chris@chris-wilson.co.uk> [x86-32] Tested-by: Pavel Machek <pavel@ucw.cz> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> [5.8+] Link: https://lkml.kernel.org/r/20200821123746.16904-1-joro@8bytes.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm: slub: fix conversion of freelist_corrupted()Eugeniu Rosca
Commit 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in deactivate_slab()") suffered an update when picked up from LKML [1]. Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()' created a no-op statement. Fix it by sticking to the behavior intended in the original patch [1]. In addition, make freelist_corrupted() immune to passing NULL instead of &freelist. The issue has been spotted via static analysis and code review. [1] https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zhang@oracle.com/ Fixes: 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in deactivate_slab()") Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dongli Zhang <dongli.zhang@oracle.com> Cc: Joe Jin <joe.jin@oracle.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20200824130643.10291-1-erosca@de.adit-jv.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05mm: memcg: fix memcg reclaim soft lockupXunlei Pang
We've met softlockup with "CONFIG_PREEMPT_NONE=y", when the target memcg doesn't have any reclaimable memory. It can be easily reproduced as below: watchdog: BUG: soft lockup - CPU#0 stuck for 111s![memcg_test:2204] CPU: 0 PID: 2204 Comm: memcg_test Not tainted 5.9.0-rc2+ #12 Call Trace: shrink_lruvec+0x49f/0x640 shrink_node+0x2a6/0x6f0 do_try_to_free_pages+0xe9/0x3e0 try_to_free_mem_cgroup_pages+0xef/0x1f0 try_charge+0x2c1/0x750 mem_cgroup_charge+0xd7/0x240 __add_to_page_cache_locked+0x2fd/0x370 add_to_page_cache_lru+0x4a/0xc0 pagecache_get_page+0x10b/0x2f0 filemap_fault+0x661/0xad0 ext4_filemap_fault+0x2c/0x40 __do_fault+0x4d/0xf9 handle_mm_fault+0x1080/0x1790 It only happens on our 1-vcpu instances, because there's no chance for oom reaper to run to reclaim the to-be-killed process. Add a cond_resched() at the upper shrink_node_memcgs() to solve this issue, this will mean that we will get a scheduling point for each memcg in the reclaimed hierarchy without any dependency on the reclaimable memory in that memcg thus making it more predictable. Suggested-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Chris Down <chris@chrisdown.name> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: http://lkml.kernel.org/r/1598495549-67324-1-git-send-email-xlpang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-05memcg: fix use-after-free in uncharge_batchMichal Hocko
syzbot has reported an use-after-free in the uncharge_batch path BUG: KASAN: use-after-free in instrument_atomic_write include/linux/instrumented.h:71 [inline] BUG: KASAN: use-after-free in atomic64_sub_return include/asm-generic/atomic-instrumented.h:970 [inline] BUG: KASAN: use-after-free in atomic_long_sub_return include/asm-generic/atomic-long.h:113 [inline] BUG: KASAN: use-after-free in page_counter_cancel mm/page_counter.c:54 [inline] BUG: KASAN: use-after-free in page_counter_uncharge+0x3d/0xc0 mm/page_counter.c:155 Write of size 8 at addr ffff8880371c0148 by task syz-executor.0/9304 CPU: 0 PID: 9304 Comm: syz-executor.0 Not tainted 5.8.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1f0/0x31e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 check_memory_region_inline mm/kasan/generic.c:183 [inline] check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:192 instrument_atomic_write include/linux/instrumented.h:71 [inline] atomic64_sub_return include/asm-generic/atomic-instrumented.h:970 [inline] atomic_long_sub_return include/asm-generic/atomic-long.h:113 [inline] page_counter_cancel mm/page_counter.c:54 [inline] page_counter_uncharge+0x3d/0xc0 mm/page_counter.c:155 uncharge_batch+0x6c/0x350 mm/memcontrol.c:6764 uncharge_page+0x115/0x430 mm/memcontrol.c:6796 uncharge_list mm/memcontrol.c:6835 [inline] mem_cgroup_uncharge_list+0x70/0xe0 mm/memcontrol.c:6877 release_pages+0x13a2/0x1550 mm/swap.c:911 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline] tlb_flush_mmu_free mm/mmu_gather.c:242 [inline] tlb_flush_mmu+0x780/0x910 mm/mmu_gather.c:249 tlb_finish_mmu+0xcb/0x200 mm/mmu_gather.c:328 exit_mmap+0x296/0x550 mm/mmap.c:3185 __mmput+0x113/0x370 kernel/fork.c:1076 exit_mm+0x4cd/0x550 kernel/exit.c:483 do_exit+0x576/0x1f20 kernel/exit.c:793 do_group_exit+0x161/0x2d0 kernel/exit.c:903 get_signal+0x139b/0x1d30 kernel/signal.c:2743 arch_do_signal+0x33/0x610 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:135 [inline] exit_to_user_mode_prepare+0x8d/0x1b0 kernel/entry/common.c:166 syscall_exit_to_user_mode+0x5e/0x1a0 kernel/entry/common.c:241 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Commit 1a3e1f40962c ("mm: memcontrol: decouple reference counting from page accounting") reworked the memcg lifetime to be bound the the struct page rather than charges. It also removed the css_put_many from uncharge_batch and that is causing the above splat. uncharge_batch() is supposed to uncharge accumulated charges for all pages freed from the same memcg. The queuing is done by uncharge_page which however drops the memcg reference after it adds charges to the batch. If the current page happens to be the last one holding the reference for its memcg then the memcg is OK to go and the next page to be freed will trigger batched uncharge which needs to access the memcg which is gone already. Fix the issue by taking a reference for the memcg in the current batch. Fixes: 1a3e1f40962c ("mm: memcontrol: decouple reference counting from page accounting") Reported-by: syzbot+b305848212deec86eabe@syzkaller.appspotmail.com Reported-by: syzbot+b5ea6fb6f139c8b9482b@syzkaller.appspotmail.com Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <guro@fb.com> Cc: Hugh Dickins <hughd@google.com> Link: https://lkml.kernel.org/r/20200820090341.GC5033@dhcp22.suse.cz Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-04Merge branch 'simplify-do_wp_page'Linus Torvalds
Merge emailed patches from Peter Xu: "This is a small series that I picked up from Linus's suggestion to simplify cow handling (and also make it more strict) by checking against page refcounts rather than mapcounts. This makes uffd-wp work again (verified by running upmapsort)" Note: this is horrendously bad timing, and making this kind of fundamental vm change after -rc3 is not at all how things should work. The saving grace is that it really is a a nice simplification: 8 files changed, 29 insertions(+), 120 deletions(-) The reason for the bad timing is that it turns out that commit 17839856fd58 ("gup: document and work around 'COW can break either way' issue" broke not just UFFD functionality (as Peter noticed), but Mikulas Patocka also reports that it caused issues for strace when running in a DAX environment with ext4 on a persistent memory setup. And we can't just revert that commit without re-introducing the original issue that is a potential security hole, so making COW stricter (and in the process much simpler) is a step to then undoing the forced COW that broke other uses. Link: https://lore.kernel.org/lkml/alpine.LRH.2.02.2009031328040.6929@file01.intranet.prod.int.rdu2.redhat.com/ * emailed patches from Peter Xu <peterx@redhat.com>: mm: Add PGREUSE counter mm/gup: Remove enfornced COW mechanism mm/ksm: Remove reuse_ksm_page() mm: do_wp_page() simplification
2020-09-04mm: Add PGREUSE counterPeter Xu
This accounts for wp_page_reuse() case, where we reused a page for COW. Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-04mm/gup: Remove enfornced COW mechanismPeter Xu
With the more strict (but greatly simplified) page reuse logic in do_wp_page(), we can safely go back to the world where cow is not enforced with writes. This essentially reverts commit 17839856fd58 ("gup: document and work around 'COW can break either way' issue"). There are some context differences due to some changes later on around it: 2170ecfa7688 ("drm/i915: convert get_user_pages() --> pin_user_pages()", 2020-06-03) 376a34efa4ee ("mm/gup: refactor and de-duplicate gup_fast() code", 2020-06-03) Some lines moved back and forth with those, but this revert patch should have striped out and covered all the enforced cow bits anyways. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-04mm/ksm: Remove reuse_ksm_page()Peter Xu
Remove the function as the last reference has gone away with the do_wp_page() changes. Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-04mm: do_wp_page() simplificationLinus Torvalds
How about we just make sure we're the only possible valid user fo the page before we bother to reuse it? Simplify, simplify, simplify. And get rid of the nasty serialization on the page lock at the same time. [peterx: add subject prefix] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-04memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERICRoger Pau Monne
This is in preparation for the logic behind MEMORY_DEVICE_DEVDAX also being used by non DAX devices. No functional change intended. Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Link: https://lore.kernel.org/r/20200901083326.21264-3-roger.pau@citrix.com Signed-off-by: Juergen Gross <jgross@suse.com>
2020-09-03Merge branch 'gate-page-refcount' (patches from Dave Hansen)Linus Torvalds
Merge gate page refcount fix from Dave Hansen: "During the conversion over to pin_user_pages(), gate pages were missed. The fix is pretty simple, and is accompanied by a new test from Andy which probably would have caught this earlier" * emailed patches from Dave Hansen <dave.hansen@linux.intel.com>: selftests/x86/test_vsyscall: Improve the process_vm_readv() test mm: fix pin vs. gup mismatch with gate pages
2020-09-03mm: fix pin vs. gup mismatch with gate pagesDave Hansen
Gate pages were missed when converting from get to pin_user_pages(). This can lead to refcount imbalances. This is reliably and quickly reproducible running the x86 selftests when vsyscall=emulate is enabled (the default). Fix by using try_grab_page() with appropriate flags passed. The long story: Today, pin_user_pages() and get_user_pages() are similar interfaces for manipulating page reference counts. However, "pins" use a "bias" value and manipulate the actual reference count by 1024 instead of 1 used by plain "gets". That means that pin_user_pages() must be matched with unpin_user_pages() and can't be mixed with a plain put_user_pages() or put_page(). Enter gate pages, like the vsyscall page. They are pages usually in the kernel image, but which are mapped to userspace. Userspace is allowed access to them, including interfaces using get/pin_user_pages(). The refcount of these kernel pages is manipulated just like a normal user page on the get/pin side so that the put/unpin side can work the same for normal user pages or gate pages. get_gate_page() uses try_get_page() which only bumps the refcount by 1, not 1024, even if called in the pin_user_pages() path. If someone pins a gate page, this happens: pin_user_pages() get_gate_page() try_get_page() // bump refcount +1 ... some time later unpin_user_pages() page_ref_sub_and_test(page, 1024)) ... and boom, we get a refcount off by 1023. This is reliably and quickly reproducible running the x86 selftests when booted with vsyscall=emulate (the default). The selftests use ptrace(), but I suspect anything using pin_user_pages() on gate pages could hit this. To fix it, simply use try_grab_page() instead of try_get_page(), and pass 'gup_flags' in so that FOLL_PIN can be respected. This bug traces back to the very beginning of the FOLL_PIN support in commit 3faa52c03f44 ("mm/gup: track FOLL_PIN pages"), which showed up in the 5.7 release. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Fixes: 3faa52c03f44 ("mm/gup: track FOLL_PIN pages") Reported-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Andy Lutomirski <luto@kernel.org> Cc: x86@kernel.org Cc: Jann Horn <jannh@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-30Merge tag 'powerpc-5.9-4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fixes from Michael Ellerman: - Revert our removal of PROT_SAO, at least one user expressed an interest in using it on Power9. Instead don't allow it to be used in guests unless enabled explicitly at compile time. - A fix for a crash introduced by a recent change to FP handling. - Revert a change to our idle code that left Power10 with no idle support. - One minor fix for the new scv system call path to set PPR. - Fix a crash in our "generic" PMU if branch stack events were enabled. - A fix for the IMC PMU, to correctly identify host kernel samples. - The ADB_PMU powermac code was found to be incompatible with VMAP_STACK, so make them incompatible in Kconfig until the code can be fixed. - A build fix in drivers/video/fbdev/controlfb.c, and a documentation fix. Thanks to Alexey Kardashevskiy, Athira Rajeev, Christophe Leroy, Giuseppe Sacco, Madhavan Srinivasan, Milton Miller, Nicholas Piggin, Pratik Rajesh Sampat, Randy Dunlap, Shawn Anastasio, Vaidyanathan Srinivasan. * tag 'powerpc-5.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/32s: Disable VMAP stack which CONFIG_ADB_PMU Revert "powerpc/powernv/idle: Replace CPU feature check with PVR check" powerpc/perf: Fix reading of MSR[HV/PR] bits in trace-imc powerpc/perf: Fix crashes with generic_compat_pmu & BHRB powerpc/64s: Fix crash in load_fp_state() due to fpexc_mode powerpc/64s: scv entry should set PPR Documentation/powerpc: fix malformed table in syscall64-abi video: fbdev: controlfb: Fix build for COMPILE_TEST=y && PPC_PMAC=n selftests/powerpc: Update PROT_SAO test to skip ISA 3.1 powerpc/64s: Disallow PROT_SAO in LPARs by default Revert "powerpc/64s: Remove PROT_SAO support"
2020-08-24Revert "powerpc/64s: Remove PROT_SAO support"Shawn Anastasio
This reverts commit 5c9fa16e8abd342ce04dc830c1ebb2a03abf6c05. Since PROT_SAO can still be useful for certain classes of software, reintroduce it. Concerns about guest migration for LPARs using SAO will be addressed next. Signed-off-by: Shawn Anastasio <shawn@anastas.io> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200821185558.35561-2-shawn@anastas.io
2020-08-21mm, page_alloc: fix core hung in free_pcppages_bulk()Charan Teja Reddy
The following race is observed with the repeated online, offline and a delay between two successive online of memory blocks of movable zone. P1 P2 Online the first memory block in the movable zone. The pcp struct values are initialized to default values,i.e., pcp->high = 0 & pcp->batch = 1. Allocate the pages from the movable zone. Try to Online the second memory block in the movable zone thus it entered the online_pages() but yet to call zone_pcp_update(). This process is entered into the exit path thus it tries to release the order-0 pages to pcp lists through free_unref_page_commit(). As pcp->high = 0, pcp->count = 1 proceed to call the function free_pcppages_bulk(). Update the pcp values thus the new pcp values are like, say, pcp->high = 378, pcp->batch = 63. Read the pcp's batch value using READ_ONCE() and pass the same to free_pcppages_bulk(), pcp values passed here are, batch = 63, count = 1. Since num of pages in the pcp lists are less than ->batch, then it will stuck in while(list_empty(list)) loop with interrupts disabled thus a core hung. Avoid this by ensuring free_pcppages_bulk() is called with proper count of pcp list pages. The mentioned race is some what easily reproducible without [1] because pcp's are not updated for the first memory block online and thus there is a enough race window for P2 between alloc+free and pcp struct values update through onlining of second memory block. With [1], the race still exists but it is very narrow as we update the pcp struct values for the first memory block online itself. This is not limited to the movable zone, it could also happen in cases with the normal zone (e.g., hotplug to a node that only has DMA memory, or no other memory yet). [1]: https://patchwork.kernel.org/patch/11696389/ Fixes: 5f8dcc21211a ("page-allocator: split per-cpu list into one-list-per-migrate-type") Signed-off-by: Charan Teja Reddy <charante@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Vinayak Menon <vinmenon@codeaurora.org> Cc: <stable@vger.kernel.org> [2.6+] Link: http://lkml.kernel.org/r/1597150703-19003-1-git-send-email-charante@codeaurora.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-21mm: include CMA pages in lowmem_reserve at bootDoug Berger
The lowmem_reserve arrays provide a means of applying pressure against allocations from lower zones that were targeted at higher zones. Its values are a function of the number of pages managed by higher zones and are assigned by a call to the setup_per_zone_lowmem_reserve() function. The function is initially called at boot time by the function init_per_zone_wmark_min() and may be called later by accesses of the /proc/sys/vm/lowmem_reserve_ratio sysctl file. The function init_per_zone_wmark_min() was moved up from a module_init to a core_initcall to resolve a sequencing issue with khugepaged. Unfortunately this created a sequencing issue with CMA page accounting. The CMA pages are added to the managed page count of a zone when cma_init_reserved_areas() is called at boot also as a core_initcall. This makes it uncertain whether the CMA pages will be added to the managed page counts of their zones before or after the call to init_per_zone_wmark_min() as it becomes dependent on link order. With the current link order the pages are added to the managed count after the lowmem_reserve arrays are initialized at boot. This means the lowmem_reserve values at boot may be lower than the values used later if /proc/sys/vm/lowmem_reserve_ratio is accessed even if the ratio values are unchanged. In many cases the difference is not significant, but for example an ARM platform with 1GB of memory and the following memory layout cma: Reserved 256 MiB at 0x0000000030000000 Zone ranges: DMA [mem 0x0000000000000000-0x000000002fffffff] Normal empty HighMem [mem 0x0000000030000000-0x000000003fffffff] would result in 0 lowmem_reserve for the DMA zone. This would allow userspace to deplete the DMA zone easily. Funnily enough $ cat /proc/sys/vm/lowmem_reserve_ratio would fix up the situation because as a side effect it forces setup_per_zone_lowmem_reserve. This commit breaks the link order dependency by invoking init_per_zone_wmark_min() as a postcore_initcall so that the CMA pages have the chance to be properly accounted in their zone(s) and allowing the lowmem_reserve arrays to receive consistent values. Fixes: bc22af74f271 ("mm: update min_free_kbytes from khugepaged after core initialization") Signed-off-by: Doug Berger <opendmb@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jason Baron <jbaron@akamai.com> Cc: David Rientjes <rientjes@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1597423766-27849-1-git-send-email-opendmb@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-21mm/rodata_test.c: fix missing function declarationLeon Romanovsky
The compilation with CONFIG_DEBUG_RODATA_TEST set produces the following warning due to the missing include. mm/rodata_test.c:15:6: warning: no previous prototype for 'rodata_test' [-Wmissing-prototypes] 15 | void rodata_test(void) | ^~~~~~~~~~~ Fixes: 2959a5f726f6 ("mm: add arch-independent testcases for RODATA") Signed-off-by: Leon Romanovsky <leonro@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lkml.kernel.org/r/20200819080026.918134-1-leon@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-21mm/vunmap: add cond_resched() in vunmap_pmd_rangeAneesh Kumar K.V
Like zap_pte_range add cond_resched so that we can avoid softlockups as reported below. On non-preemptible kernel with large I/O map region (like the one we get when using persistent memory with sector mode), an unmap of the namespace can report below softlockups. 22724.027334] watchdog: BUG: soft lockup - CPU#49 stuck for 23s! [ndctl:50777] NIP [c0000000000dc224] plpar_hcall+0x38/0x58 LR [c0000000000d8898] pSeries_lpar_hpte_invalidate+0x68/0xb0 Call Trace: flush_hash_page+0x114/0x200 hpte_need_flush+0x2dc/0x540 vunmap_page_range+0x538/0x6f0 free_unmap_vmap_area+0x30/0x70 remove_vm_area+0xfc/0x140 __vunmap+0x68/0x270 __iounmap.part.0+0x34/0x60 memunmap+0x54/0x70 release_nodes+0x28c/0x300 device_release_driver_internal+0x16c/0x280 unbind_store+0x124/0x170 drv_attr_store+0x44/0x60 sysfs_kf_write+0x64/0x90 kernfs_fop_write+0x1b0/0x290 __vfs_write+0x3c/0x70 vfs_write+0xd8/0x260 ksys_write+0xdc/0x130 system_call+0x5c/0x70 Reported-by: Harish Sriram <harish@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200807075933.310240-1-aneesh.kumar@linux.ibm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-21khugepaged: adjust VM_BUG_ON_MM() in __khugepaged_enter()Hugh Dickins
syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in __khugepaged_enter(): yes, when one thread is about to dump core, has set core_state, and is waiting for others, another might do something calling __khugepaged_enter(), which now crashes because I lumped the core_state test (known as "mmget_still_valid") into khugepaged_test_exit(). I still think it's best to lump them together, so just in this exceptional case, check mm->mm_users directly instead of khugepaged_test_exit(). Fixes: bbe98f9cadff ("khugepaged: khugepaged_test_exit() check mmget_still_valid()") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Yang Shi <shy828301@gmail.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Song Liu <songliubraving@fb.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Eric Dumazet <edumazet@google.com> Cc: <stable@vger.kernel.org> [4.8+] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvils Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-21hugetlb_cgroup: convert comma to semicolonXu Wang
Replace a comma between expression statements by a semicolon. Fixes: faced7e0806cf4 ("mm: hugetlb controller for cgroups v2") Signed-off-by: Xu Wang <vulab@iscas.ac.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Tejun Heo <tj@kernel.org> Cc: Giuseppe Scrivano <gscrivan@redhat.com> Link: http://lkml.kernel.org/r/20200818064333.21759-1-vulab@iscas.ac.cn Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-18mm/memory.c: skip spurious TLB flush for retried page faultYang Shi
Recently we found regression when running will_it_scale/page_fault3 test on ARM64. Over 70% down for the multi processes cases and over 20% down for the multi threads cases. It turns out the regression is caused by commit 89b15332af7c ("mm: drop mmap_sem before calling balance_dirty_pages() in write fault"). The test mmaps a memory size file then write to the mapping, this would make all memory dirty and trigger dirty pages throttle, that upstream commit would release mmap_sem then retry the page fault. The retried page fault would see correct PTEs installed then just fall through to spurious TLB flush. The regression is caused by the excessive spurious TLB flush. It is fine on x86 since x86's spurious TLB flush is no-op. We could just skip the spurious TLB flush to mitigate the regression. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Xu Yu <xuyu@linux.alibaba.com> Debugged-by: Xu Yu <xuyu@linux.alibaba.com> Tested-by: Xu Yu <xuyu@linux.alibaba.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Yang Shi <shy828301@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-15Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge more updates from Andrew Morton: "Subsystems affected by this patch series: mm/hotfixes, lz4, exec, mailmap, mm/thp, autofs, sysctl, mm/kmemleak, mm/misc and lib" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (35 commits) virtio: pci: constify ioreadX() iomem argument (as in generic implementation) ntb: intel: constify ioreadX() iomem argument (as in generic implementation) rtl818x: constify ioreadX() iomem argument (as in generic implementation) iomap: constify ioreadX() iomem argument (as in generic implementation) sh: use generic strncpy() sh: clkfwk: remove r8/r16/r32 include/asm-generic/vmlinux.lds.h: align ro_after_init mm: annotate a data race in page_zonenum() mm/swap.c: annotate data races for lru_rotate_pvecs mm/rmap: annotate a data race at tlb_flush_batched mm/mempool: fix a data race in mempool_free() mm/list_lru: fix a data race in list_lru_count_one mm/memcontrol: fix a data race in scan count mm/page_counter: fix various data races at memsw mm/swapfile: fix and annotate various data races mm/filemap.c: fix a data race in filemap_fault() mm/swap_state: mark various intentional data races mm/page_io: mark various intentional data races mm/frontswap: mark various intentional data races mm/kmemleak: silence KCSAN splats in checksum ...
2020-08-14mm/swap.c: annotate data races for lru_rotate_pvecsQian Cai
Read to lru_add_pvec->nr could be interrupted and then write to the same variable. The write has local interrupt disabled, but the plain reads result in data races. However, it is unlikely the compilers could do much damage here given that lru_add_pvec->nr is a "unsigned char" and there is an existing compiler barrier. Thus, annotate the reads using the data_race() macro. The data races were reported by KCSAN, BUG: KCSAN: data-race in lru_add_drain_cpu / rotate_reclaimable_page write to 0xffff9291ebcb8a40 of 1 bytes by interrupt on cpu 23: rotate_reclaimable_page+0x2df/0x490 pagevec_add at include/linux/pagevec.h:81 (inlined by) rotate_reclaimable_page at mm/swap.c:259 end_page_writeback+0x1b5/0x2b0 end_swap_bio_write+0x1d0/0x280 bio_endio+0x297/0x560 dec_pending+0x218/0x430 [dm_mod] clone_endio+0xe4/0x2c0 [dm_mod] bio_endio+0x297/0x560 blk_update_request+0x201/0x920 scsi_end_request+0x6b/0x4a0 scsi_io_completion+0xb7/0x7e0 scsi_finish_command+0x1ed/0x2a0 scsi_softirq_done+0x1c9/0x1d0 blk_done_softirq+0x181/0x1d0 __do_softirq+0xd9/0x57c irq_exit+0xa2/0xc0 do_IRQ+0x8b/0x190 ret_from_intr+0x0/0x42 delay_tsc+0x46/0x80 __const_udelay+0x3c/0x40 __udelay+0x10/0x20 kcsan_setup_watchpoint+0x202/0x3a0 __tsan_read1+0xc2/0x100 lru_add_drain_cpu+0xb8/0x3f0 lru_add_drain+0x25/0x40 shrink_active_list+0xe1/0xc80 shrink_lruvec+0x766/0xb70 shrink_node+0x2d6/0xca0 do_try_to_free_pages+0x1f7/0x9a0 try_to_free_pages+0x252/0x5b0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x16e/0x6f0 __handle_mm_fault+0xcd5/0xd40 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffff9291ebcb8a40 of 1 bytes by task 37761 on cpu 23: lru_add_drain_cpu+0xb8/0x3f0 lru_add_drain_cpu at mm/swap.c:602 lru_add_drain+0x25/0x40 shrink_active_list+0xe1/0xc80 shrink_lruvec+0x766/0xb70 shrink_node+0x2d6/0xca0 do_try_to_free_pages+0x1f7/0x9a0 try_to_free_pages+0x252/0x5b0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x16e/0x6f0 __handle_mm_fault+0xcd5/0xd40 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 2 locks held by oom02/37761: #0: ffff9281e5928808 (&mm->mmap_sem#2){++++}, at: do_page_fault #1: ffffffffb3ade380 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part irq event stamp: 1949217 trace_hardirqs_on_thunk+0x1a/0x1c __do_softirq+0x2e7/0x57c __do_softirq+0x34c/0x57c irq_exit+0xa2/0xc0 Reported by Kernel Concurrency Sanitizer on: CPU: 23 PID: 37761 Comm: oom02 Not tainted 5.6.0-rc3-next-20200226+ #6 Hardware name: HP ProLiant BL660c Gen9, BIOS I38 10/17/2018 Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/20200228044018.1263-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/rmap: annotate a data race at tlb_flush_batchedQian Cai
mm->tlb_flush_batched could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in flush_tlb_batched_pending / try_to_unmap_one write to 0xffff93f754880bd0 of 1 bytes by task 822 on cpu 6: try_to_unmap_one+0x59a/0x1ab0 set_tlb_ubc_flush_pending at mm/rmap.c:635 (inlined by) try_to_unmap_one at mm/rmap.c:1538 rmap_walk_anon+0x296/0x650 rmap_walk+0xdf/0x100 try_to_unmap+0x18a/0x2f0 shrink_page_list+0xef6/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 balance_pgdat+0x652/0xd90 kswapd+0x396/0x8d0 kthread+0x1e0/0x200 ret_from_fork+0x27/0x50 read to 0xffff93f754880bd0 of 1 bytes by task 6364 on cpu 4: flush_tlb_batched_pending+0x29/0x90 flush_tlb_batched_pending at mm/rmap.c:682 change_p4d_range+0x5dd/0x1030 change_pte_range at mm/mprotect.c:44 (inlined by) change_pmd_range at mm/mprotect.c:212 (inlined by) change_pud_range at mm/mprotect.c:240 (inlined by) change_p4d_range at mm/mprotect.c:260 change_protection+0x222/0x310 change_prot_numa+0x3e/0x60 task_numa_work+0x219/0x350 task_work_run+0xed/0x140 prepare_exit_to_usermode+0x2cc/0x2e0 ret_from_intr+0x32/0x42 Reported by Kernel Concurrency Sanitizer on: CPU: 4 PID: 6364 Comm: mtest01 Tainted: G W L 5.5.0-next-20200210+ #5 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 flush_tlb_batched_pending() is under PTL but the write is not, but mm->tlb_flush_batched is only a bool type, so the value is unlikely to be shattered. Thus, mark it as an intentional data race by using the data race macro. Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/1581450783-8262-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/mempool: fix a data race in mempool_free()Qian Cai
mempool_t pool.curr_nr could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in mempool_free / remove_element write to 0xffffffffa937638c of 4 bytes by task 6359 on cpu 113: remove_element+0x4a/0x1c0 remove_element at mm/mempool.c:132 mempool_alloc+0x102/0x210 (inlined by) mempool_alloc at mm/mempool.c:399 bio_alloc_bioset+0x106/0x2c0 get_swap_bio+0x49/0x230 __swap_writepage+0x680/0xc30 swap_writepage+0x9c/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 <snip> read to 0xffffffffa937638c of 4 bytes by interrupt on cpu 64: mempool_free+0x3e/0x150 mempool_free at mm/mempool.c:492 bio_free+0x192/0x280 bio_put+0x91/0xd0 end_swap_bio_write+0x1d8/0x280 bio_endio+0x2c2/0x5b0 dec_pending+0x22b/0x440 [dm_mod] clone_endio+0xe4/0x2c0 [dm_mod] bio_endio+0x2c2/0x5b0 blk_update_request+0x217/0x940 scsi_end_request+0x6b/0x4d0 scsi_io_completion+0xb7/0x7e0 scsi_finish_command+0x223/0x310 scsi_softirq_done+0x1d5/0x210 blk_mq_complete_request+0x224/0x250 scsi_mq_done+0xc2/0x250 pqi_raid_io_complete+0x5a/0x70 [smartpqi] pqi_irq_handler+0x150/0x1410 [smartpqi] __handle_irq_event_percpu+0x90/0x540 handle_irq_event_percpu+0x49/0xd0 handle_irq_event+0x85/0xca handle_edge_irq+0x13f/0x3e0 do_IRQ+0x86/0x190 <snip> Since the write is under pool->lock but the read is done as lockless. Even though the commit 5b990546e334 ("mempool: fix and document synchronization and memory barrier usage") introduced the smp_wmb() and smp_rmb() pair to improve the situation, it is adequate to protect it from data races which could lead to a logic bug, so fix it by adding READ_ONCE() for the read. Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/1581446384-2131-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/list_lru: fix a data race in list_lru_count_oneQian Cai
struct list_lru_one l.nr_items could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in list_lru_count_one / list_lru_isolate_move write to 0xffffa102789c4510 of 8 bytes by task 823 on cpu 39: list_lru_isolate_move+0xf9/0x130 list_lru_isolate_move at mm/list_lru.c:180 inode_lru_isolate+0x12b/0x2a0 __list_lru_walk_one+0x122/0x3d0 list_lru_walk_one+0x75/0xa0 prune_icache_sb+0x8b/0xc0 super_cache_scan+0x1b8/0x250 do_shrink_slab+0x256/0x6d0 shrink_slab+0x41b/0x4a0 shrink_node+0x35c/0xd80 balance_pgdat+0x652/0xd90 kswapd+0x396/0x8d0 kthread+0x1e0/0x200 ret_from_fork+0x27/0x50 read to 0xffffa102789c4510 of 8 bytes by task 6345 on cpu 56: list_lru_count_one+0x116/0x2f0 list_lru_count_one at mm/list_lru.c:193 super_cache_count+0xe8/0x170 do_shrink_slab+0x95/0x6d0 shrink_slab+0x41b/0x4a0 shrink_node+0x35c/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 56 PID: 6345 Comm: oom01 Tainted: G W L 5.5.0-next-20200205+ #4 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 A shattered l.nr_items could affect the shrinker behaviour due to a data race. Fix it by adding READ_ONCE() for the read. Since the writes are aligned and up to word-size, assume those are safe from data races to avoid readability issues of writing WRITE_ONCE(var, var + val). Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1581114679-5488-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/page_counter: fix various data races at memswQian Cai
Commit 3e32cb2e0a12 ("mm: memcontrol: lockless page counters") could had memcg->memsw->watermark and memcg->memsw->failcnt been accessed concurrently as reported by KCSAN, BUG: KCSAN: data-race in page_counter_try_charge / page_counter_try_charge read to 0xffff8fb18c4cd190 of 8 bytes by task 1081 on cpu 59: page_counter_try_charge+0x4d/0x150 mm/page_counter.c:138 try_charge+0x131/0xd50 mm/memcontrol.c:2405 __memcg_kmem_charge_memcg+0x58/0x140 __memcg_kmem_charge+0xcc/0x280 __alloc_pages_nodemask+0x1e1/0x450 alloc_pages_current+0xa6/0x120 pte_alloc_one+0x17/0xd0 __pte_alloc+0x3a/0x1f0 copy_p4d_range+0xc36/0x1990 copy_page_range+0x21d/0x360 dup_mmap+0x5f5/0x7a0 dup_mm+0xa2/0x240 copy_process+0x1b3f/0x3460 _do_fork+0xaa/0xa20 __x64_sys_clone+0x13b/0x170 do_syscall_64+0x91/0xb47 entry_SYSCALL_64_after_hwframe+0x49/0xbe write to 0xffff8fb18c4cd190 of 8 bytes by task 1153 on cpu 120: page_counter_try_charge+0x5b/0x150 mm/page_counter.c:139 try_charge+0x131/0xd50 mm/memcontrol.c:2405 mem_cgroup_try_charge+0x159/0x460 mem_cgroup_try_charge_delay+0x3d/0xa0 wp_page_copy+0x14d/0x930 do_wp_page+0x107/0x7b0 __handle_mm_fault+0xce6/0xd40 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 BUG: KCSAN: data-race in page_counter_try_charge / page_counter_try_charge write to 0xffff88809bbf2158 of 8 bytes by task 11782 on cpu 0: page_counter_try_charge+0x100/0x170 mm/page_counter.c:129 try_charge+0x185/0xbf0 mm/memcontrol.c:2405 __memcg_kmem_charge_memcg+0x4a/0xe0 mm/memcontrol.c:2837 __memcg_kmem_charge+0xcf/0x1b0 mm/memcontrol.c:2877 __alloc_pages_nodemask+0x26c/0x310 mm/page_alloc.c:4780 read to 0xffff88809bbf2158 of 8 bytes by task 11814 on cpu 1: page_counter_try_charge+0xef/0x170 mm/page_counter.c:129 try_charge+0x185/0xbf0 mm/memcontrol.c:2405 __memcg_kmem_charge_memcg+0x4a/0xe0 mm/memcontrol.c:2837 __memcg_kmem_charge+0xcf/0x1b0 mm/memcontrol.c:2877 __alloc_pages_nodemask+0x26c/0x310 mm/page_alloc.c:4780 Since watermark could be compared or set to garbage due to a data race which would change the code logic, fix it by adding a pair of READ_ONCE() and WRITE_ONCE() in those places. The "failcnt" counter is tolerant of some degree of inaccuracy and is only used to report stats, a data race will not be harmful, thus mark it as an intentional data race using the data_race() macro. Fixes: 3e32cb2e0a12 ("mm: memcontrol: lockless page counters") Reported-by: syzbot+f36cfe60b1006a94f9dc@syzkaller.appspotmail.com Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Link: http://lkml.kernel.org/r/1581519682-23594-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/swapfile: fix and annotate various data racesQian Cai
swap_info_struct si.highest_bit, si.swap_map[offset] and si.flags could be accessed concurrently separately as noticed by KCSAN, === si.highest_bit === write to 0xffff8d5abccdc4d4 of 4 bytes by task 5353 on cpu 24: swap_range_alloc+0x81/0x130 swap_range_alloc at mm/swapfile.c:681 scan_swap_map_slots+0x371/0xb90 get_swap_pages+0x39d/0x5c0 get_swap_page+0xf2/0x524 add_to_swap+0xe4/0x1c0 shrink_page_list+0x1795/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 read to 0xffff8d5abccdc4d4 of 4 bytes by task 6672 on cpu 70: scan_swap_map_slots+0x4a6/0xb90 scan_swap_map_slots at mm/swapfile.c:892 get_swap_pages+0x39d/0x5c0 get_swap_page+0xf2/0x524 add_to_swap+0xe4/0x1c0 shrink_page_list+0x1795/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 Reported by Kernel Concurrency Sanitizer on: CPU: 70 PID: 6672 Comm: oom01 Tainted: G W L 5.5.0-next-20200205+ #3 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 === si.swap_map[offset] === write to 0xffffbc370c29a64c of 1 bytes by task 6856 on cpu 86: __swap_entry_free_locked+0x8c/0x100 __swap_entry_free_locked at mm/swapfile.c:1209 (discriminator 4) __swap_entry_free.constprop.20+0x69/0xb0 free_swap_and_cache+0x53/0xa0 unmap_page_range+0x7f8/0x1d70 unmap_single_vma+0xcd/0x170 unmap_vmas+0x18b/0x220 exit_mmap+0xee/0x220 mmput+0x10e/0x270 do_exit+0x59b/0xf40 do_group_exit+0x8b/0x180 read to 0xffffbc370c29a64c of 1 bytes by task 6855 on cpu 20: _swap_info_get+0x81/0xa0 _swap_info_get at mm/swapfile.c:1140 free_swap_and_cache+0x40/0xa0 unmap_page_range+0x7f8/0x1d70 unmap_single_vma+0xcd/0x170 unmap_vmas+0x18b/0x220 exit_mmap+0xee/0x220 mmput+0x10e/0x270 do_exit+0x59b/0xf40 do_group_exit+0x8b/0x180 === si.flags === write to 0xffff956c8fc6c400 of 8 bytes by task 6087 on cpu 23: scan_swap_map_slots+0x6fe/0xb50 scan_swap_map_slots at mm/swapfile.c:887 get_swap_pages+0x39d/0x5c0 get_swap_page+0x377/0x524 add_to_swap+0xe4/0x1c0 shrink_page_list+0x1795/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 read to 0xffff956c8fc6c400 of 8 bytes by task 6207 on cpu 63: _swap_info_get+0x41/0xa0 __swap_info_get at mm/swapfile.c:1114 put_swap_page+0x84/0x490 __remove_mapping+0x384/0x5f0 shrink_page_list+0xff1/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 The writes are under si->lock but the reads are not. For si.highest_bit and si.swap_map[offset], data race could trigger logic bugs, so fix them by having WRITE_ONCE() for the writes and READ_ONCE() for the reads except those isolated reads where they compare against zero which a data race would cause no harm. Thus, annotate them as intentional data races using the data_race() macro. For si.flags, the readers are only interested in a single bit where a data race there would cause no issue there. [cai@lca.pw: add a missing annotation for si->flags in memory.c] Link: http://lkml.kernel.org/r/1581612647-5958-1-git-send-email-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Hugh Dickins <hughd@google.com> Link: http://lkml.kernel.org/r/1581095163-12198-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/filemap.c: fix a data race in filemap_fault()Kirill A. Shutemov
struct file_ra_state ra.mmap_miss could be accessed concurrently during page faults as noticed by KCSAN, BUG: KCSAN: data-race in filemap_fault / filemap_map_pages write to 0xffff9b1700a2c1b4 of 4 bytes by task 3292 on cpu 30: filemap_fault+0x920/0xfc0 do_sync_mmap_readahead at mm/filemap.c:2384 (inlined by) filemap_fault at mm/filemap.c:2486 __xfs_filemap_fault+0x112/0x3e0 [xfs] xfs_filemap_fault+0x74/0x90 [xfs] __do_fault+0x9e/0x220 do_fault+0x4a0/0x920 __handle_mm_fault+0xc69/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffff9b1700a2c1b4 of 4 bytes by task 3313 on cpu 32: filemap_map_pages+0xc2e/0xd80 filemap_map_pages at mm/filemap.c:2625 do_fault+0x3da/0x920 __handle_mm_fault+0xc69/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 32 PID: 3313 Comm: systemd-udevd Tainted: G W L 5.5.0-next-20200210+ #1 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 ra.mmap_miss is used to contribute the readahead decisions, a data race could be undesirable. Both the read and write is only under non-exclusive mmap_sem, two concurrent writers could even underflow the counter. Fix the underflow by writing to a local variable before committing a final store to ra.mmap_miss given a small inaccuracy of the counter should be acceptable. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Qian Cai <cai@lca.pw> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/20200211030134.1847-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/swap_state: mark various intentional data racesQian Cai
swap_cache_info.* could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in lookup_swap_cache / lookup_swap_cache write to 0xffffffff85517318 of 8 bytes by task 94138 on cpu 101: lookup_swap_cache+0x12e/0x460 lookup_swap_cache at mm/swap_state.c:322 do_swap_page+0x112/0xeb0 __handle_mm_fault+0xc7a/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffffff85517318 of 8 bytes by task 91655 on cpu 100: lookup_swap_cache+0x117/0x460 lookup_swap_cache at mm/swap_state.c:322 shmem_swapin_page+0xc7/0x9e0 shmem_getpage_gfp+0x2ca/0x16c0 shmem_fault+0xef/0x3c0 __do_fault+0x9e/0x220 do_fault+0x4a0/0x920 __handle_mm_fault+0xc69/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 100 PID: 91655 Comm: systemd-journal Tainted: G W O L 5.5.0-next-20200204+ #6 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 write to 0xffffffff8d717308 of 8 bytes by task 11365 on cpu 87: __delete_from_swap_cache+0x681/0x8b0 __delete_from_swap_cache at mm/swap_state.c:178 read to 0xffffffff8d717308 of 8 bytes by task 11275 on cpu 53: __delete_from_swap_cache+0x66e/0x8b0 __delete_from_swap_cache at mm/swap_state.c:178 Both the read and write are done as lockless. Since swap_cache_info.* are only used to print out counter information, even if any of them missed a few incremental due to data races, it will be harmless, so just mark it as an intentional data race using the data_race() macro. While at it, fix a checkpatch.pl warning, WARNING: Single statement macros should not use a do {} while (0) loop Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/20200207003715.1578-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/page_io: mark various intentional data racesQian Cai
struct swap_info_struct si.flags could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in scan_swap_map_slots / swap_readpage write to 0xffff9c77b80ac400 of 8 bytes by task 91325 on cpu 16: scan_swap_map_slots+0x6fe/0xb50 scan_swap_map_slots at mm/swapfile.c:887 get_swap_pages+0x39d/0x5c0 get_swap_page+0x377/0x524 add_to_swap+0xe4/0x1c0 shrink_page_list+0x1740/0x2820 shrink_inactive_list+0x316/0x8b0 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffff9c77b80ac400 of 8 bytes by task 5422 on cpu 7: swap_readpage+0x204/0x6a0 swap_readpage at mm/page_io.c:380 read_swap_cache_async+0xa2/0xb0 swapin_readahead+0x6a0/0x890 do_swap_page+0x465/0xeb0 __handle_mm_fault+0xc7a/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 7 PID: 5422 Comm: gmain Tainted: G W O L 5.5.0-next-20200204+ #6 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 Other reads, read to 0xffff91ea33eac400 of 8 bytes by task 11276 on cpu 120: __swap_writepage+0x140/0xc20 __swap_writepage at mm/page_io.c:289 read to 0xffff91ea33eac400 of 8 bytes by task 11264 on cpu 16: swap_set_page_dirty+0x44/0x1f4 swap_set_page_dirty at mm/page_io.c:442 The write is under &si->lock, but the reads are done as lockless. Since the reads only check for a specific bit in the flag, it is harmless even if load tearing happens. Thus, just mark them as intentional data races using the data_race() macro. [cai@lca.pw: add a missing annotation] Link: http://lkml.kernel.org/r/1581612585-5812-1-git-send-email-cai@lca.pw Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/20200207003601.1526-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/frontswap: mark various intentional data racesQian Cai
There are a few information counters that are intentionally not protected against increment races, so just annotate them using the data_race() macro. BUG: KCSAN: data-race in __frontswap_store / __frontswap_store write to 0xffffffff8b7174d8 of 8 bytes by task 6396 on cpu 103: __frontswap_store+0x2d0/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffffff8b7174d8 of 8 bytes by task 6405 on cpu 47: __frontswap_store+0x2b9/0x344 inc_frontswap_failed_stores at mm/frontswap.c:70 (inlined by) __frontswap_store at mm/frontswap.c:280 swap_writepage+0x83/0xf0 pageout+0x33e/0xae0 shrink_page_list+0x1f57/0x2870 shrink_inactive_list+0x316/0x880 shrink_lruvec+0x8dc/0x1380 shrink_node+0x317/0xd80 do_try_to_free_pages+0x1f7/0xa10 try_to_free_pages+0x26c/0x5e0 __alloc_pages_slowpath+0x458/0x1290 __alloc_pages_nodemask+0x3bb/0x450 alloc_pages_vma+0x8a/0x2c0 do_anonymous_page+0x170/0x700 __handle_mm_fault+0xc9f/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1581114499-5042-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm/kmemleak: silence KCSAN splats in checksumQian Cai
Even if KCSAN is disabled for kmemleak, update_checksum() could still call crc32() (which is outside of kmemleak.c) to dereference object->pointer. Thus, the value of object->pointer could be accessed concurrently as noticed by KCSAN, BUG: KCSAN: data-race in crc32_le_base / do_raw_spin_lock write to 0xffffb0ea683a7d50 of 4 bytes by task 23575 on cpu 12: do_raw_spin_lock+0x114/0x200 debug_spin_lock_after at kernel/locking/spinlock_debug.c:91 (inlined by) do_raw_spin_lock at kernel/locking/spinlock_debug.c:115 _raw_spin_lock+0x40/0x50 __handle_mm_fault+0xa9e/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 read to 0xffffb0ea683a7d50 of 4 bytes by task 839 on cpu 60: crc32_le_base+0x67/0x350 crc32_le_base+0x67/0x350: crc32_body at lib/crc32.c:106 (inlined by) crc32_le_generic at lib/crc32.c:179 (inlined by) crc32_le at lib/crc32.c:197 kmemleak_scan+0x528/0xd90 update_checksum at mm/kmemleak.c:1172 (inlined by) kmemleak_scan at mm/kmemleak.c:1497 kmemleak_scan_thread+0xcc/0xfa kthread+0x1e0/0x200 ret_from_fork+0x27/0x50 If a shattered value was returned due to a data race, it will be corrected in the next scan. Thus, let KCSAN ignore all reads in the region to silence KCSAN in case the write side is non-atomic. Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Marco Elver <elver@google.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: http://lkml.kernel.org/r/20200317182754.2180-1-cai@lca.pw Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm: replace hpage_nr_pages with thp_nr_pagesMatthew Wilcox (Oracle)
The thp prefix is more frequently used than hpage and we should be consistent between the various functions. [akpm@linux-foundation.org: fix mm/migrate.c] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Link: http://lkml.kernel.org/r/20200629151959.15779-6-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm: add thp_sizeMatthew Wilcox (Oracle)
This function returns the number of bytes in a THP. It is like page_size(), but compiles to just PAGE_SIZE if CONFIG_TRANSPARENT_HUGEPAGE is disabled. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Link: http://lkml.kernel.org/r/20200629151959.15779-5-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14mm: store compound_nr as well as compound_orderMatthew Wilcox (Oracle)
Patch series "THP prep patches". These are some generic cleanups and improvements, which I would like merged into mmotm soon. The first one should be a performance improvement for all users of compound pages, and the others are aimed at getting code to compile away when CONFIG_TRANSPARENT_HUGEPAGE is disabled (ie small systems). Also better documented / less confusing than the current prefix mixture of compound, hpage and thp. This patch (of 7): This removes a few instructions from functions which need to know how many pages are in a compound page. The storage used is either page->mapping on 64-bit or page->index on 32-bit. Both of these are fine to overlay on tail pages. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Link: http://lkml.kernel.org/r/20200629151959.15779-1-willy@infradead.org Link: http://lkml.kernel.org/r/20200629151959.15779-2-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14Revert "mm/vmstat.c: do not show lowmem reserve protection information of ↵Baoquan He
empty zone" This reverts commit 26e7deadaae175. Sonny reported that one of their tests started failing on the latest kernel on their Chrome OS platform. The root cause is that the above commit removed the protection line of empty zone, while the parser used in the test relies on the protection line to mark the end of each zone. Let's revert it to avoid breaking userspace testing or applications. Fixes: 26e7deadaae175 ("mm/vmstat.c: do not show lowmem reserve protection information of empty zone)" Reported-by: Sonny Rao <sonnyrao@chromium.org> Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> [5.8.x] Link: http://lkml.kernel.org/r/20200811075412.12872-1-bhe@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14dma-debug: remove debug_dma_assert_idle() functionLinus Torvalds
This remoes the code from the COW path to call debug_dma_assert_idle(), which was added many years ago. Google shows that it hasn't caught anything in the 6+ years we've had it apart from a false positive, and Hugh just noticed how it had a very unfortunate spinlock serialization in the COW path. He fixed that issue the previous commit (a85ffd59bd36: "dma-debug: fix debug_dma_assert_idle(), use rcu_read_lock()"), but let's see if anybody even notices when we remove this function entirely. NOTE! We keep the dma tracking infrastructure that was added by the commit that introduced it. Partly to make it easier to resurrect this debug code if we ever deside to, and partly because that tracking by pfn and offset looks quite reasonable. The problem with this debug code was simply that it was expensive and didn't seem worth it, not that it was wrong per se. Acked-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-13mm: memcontrol: fix warning when allocating the root cgroupJohannes Weiner
Commit 3e38e0aaca9e ("mm: memcg: charge memcg percpu memory to the parent cgroup") adds memory tracking to the memcg kernel structures themselves to make cgroups liable for the memory they are consuming through the allocation of child groups (which can be significant). This code is a bit awkward as it's spread out through several functions: The outermost function does memalloc_use_memcg(parent) to set up current->active_memcg, which designates which cgroup to charge, and the inner functions pass GFP_ACCOUNT to request charging for specific allocations. To make sure this dependency is satisfied at all times - to make sure we don't randomly charge whoever is calling the functions - the inner functions warn on !current->active_memcg. However, this triggers a false warning when the root memcg itself is allocated. No parent exists in this case, and so current->active_memcg is rightfully NULL. It's a false positive, not indicative of a bug. Delete the warnings for now, we can revisit this later. Fixes: 3e38e0aaca9e ("mm: memcg: charge memcg percpu memory to the parent cgroup") Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Roman Gushchin <guro@fb.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12mm/gup: remove task_struct pointer for all gup codePeter Xu
After the cleanup of page fault accounting, gup does not need to pass task_struct around any more. Remove that parameter in the whole gup stack. Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Link: http://lkml.kernel.org/r/20200707225021.200906-26-peterx@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-07 01:39:23 +0000