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The PE for root bus (root PE) can be removed because of PCI hot
remove in EEH recovery path for fenced PHB error. We need update
@phb->root_pe_populated accordingly so that the root PE can be
populated again in forthcoming PCI hot add path. Also, the PE
shouldn't be destroyed as it's global and reserved resource.
Fixes: c5f7700bbd2e ("powerpc/powernv: Dynamically release PE")
Reported-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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really ugly, but apparently avr32 compilers turns access_ok() into
something so bad that they want it in assembler. Left that way,
zeroing added in inline wrapper.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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It could be done in exception-handling bits in __get_user_b() et.al.,
but the surgery involved would take more knowledge of sh64 details
than I have or _want_ to have.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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* should zero on any failure
* __get_user() should use __copy_from_user(), not copy_from_user()
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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should clear on access_ok() failures. Also remove the useless
range truncation logics.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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... that should zero on faults. Also remove the <censored> helpful
logics wrt range truncation copied from ppc32. Where it had ever
been needed only in case of copy_from_user() *and* had not been merged
into the mainline until a month after the need had disappeared.
A decade before openrisc went into mainline, I might add...
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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a) should not leave crap on fault
b) should _not_ require access_ok() in any cases.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al reported potential issue with ARC get_user() as it wasn't clearing
out destination pointer in case of fault due to bad address etc.
Verified using following
| {
| u32 bogus1 = 0xdeadbeef;
| u64 bogus2 = 0xdead;
| int rc1, rc2;
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| pr_info("Orig values %x %llx\n", bogus1, bogus2);
| rc1 = get_user(bogus1, (u32 __user *)0x40000000);
| rc2 = get_user(bogus2, (u64 __user *)0x50000000);
| pr_info("access %d %d, new values %x %llx\n",
| rc1, rc2, bogus1, bogus2);
| }
| [ARCLinux]# insmod /mnt/kernel-module/qtn.ko
| Orig values deadbeef dead
| access -14 -14, new values 0 0
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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It's -EFAULT, not -1 (and contrary to the comment in there,
__strnlen_user() can return 0 - on faults).
Cc: stable@vger.kernel.org
Acked-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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It should check access_ok(). Otherwise a bunch of places turn into
trivially exploitable rootholes.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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* copy_from_user() on access_ok() failure ought to zero the destination
* none of those primitives should skip the access_ok() check in case of
small constant size.
Cc: stable@vger.kernel.org
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"Three fixes:
- AMD microcode loading fix with randomization
- an lguest tooling fix
- and an APIC enumeration boundary condition fix"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/apic: Fix num_processors value in case of failure
tools/lguest: Don't bork the terminal in case of wrong args
x86/microcode/AMD: Fix load of builtin microcode with randomized memory
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"This contains:
- a set of fixes found by directed-random perf fuzzing efforts by
Vince Weaver, Alexander Shishkin and Peter Zijlstra
- a cqm driver crash fix
- an AMD uncore driver use after free fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Fix PEBSv3 record drain
perf/x86/intel/bts: Kill a silly warning
perf/x86/intel/bts: Fix BTS PMI detection
perf/x86/intel/bts: Fix confused ordering of PMU callbacks
perf/core: Fix aux_mmap_count vs aux_refcount order
perf/core: Fix a race between mmap_close() and set_output() of AUX events
perf/x86/amd/uncore: Prevent use after free
perf/x86/intel/cqm: Check cqm/mbm enabled state in event init
perf/core: Remove WARN from perf_event_read()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI fixes from Ingo Molnar:
"This contains a Xen fix, an arm64 fix and a race condition /
robustization set of fixes related to ExitBootServices() usage and
boundary conditions"
* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/efi: Use efi_exit_boot_services()
efi/libstub: Use efi_exit_boot_services() in FDT
efi/libstub: Introduce ExitBootServices helper
efi/libstub: Allocate headspace in efi_get_memory_map()
efi: Fix handling error value in fdt_find_uefi_params
efi: Make for_each_efi_memory_desc_in_map() cope with running on Xen
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The espfix64 setup code was a bit inscrutible and contained an
unnecessary push of RAX. Remove that push, update all the stack
offsets to match, and document the whole mess.
Reported-By: Borislav Petkov <bp@alien8.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e5459eb10cf1175c8b36b840bc425f210d045f35.1473717910.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The AES-CTR glue code avoids calling into the blkcipher API for the
tail portion of the walk, by comparing the remainder of walk.nbytes
modulo AES_BLOCK_SIZE with the residual nbytes, and jumping straight
into the tail processing block if they are equal. This tail processing
block checks whether nbytes != 0, and does nothing otherwise.
However, in case of an allocation failure in the blkcipher layer, we
may enter this code with walk.nbytes == 0, while nbytes > 0. In this
case, we should not dereference the source and destination pointers,
since they may be NULL. So instead of checking for nbytes != 0, check
for (walk.nbytes % AES_BLOCK_SIZE) != 0, which implies the former in
non-error conditions.
Fixes: 49788fe2a128 ("arm64/crypto: AES-ECB/CBC/CTR/XTS using ARMv8 NEON and Crypto Extensions")
Cc: stable@vger.kernel.org
Reported-by: xiakaixu <xiakaixu@huawei.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The AES-CTR glue code avoids calling into the blkcipher API for the
tail portion of the walk, by comparing the remainder of walk.nbytes
modulo AES_BLOCK_SIZE with the residual nbytes, and jumping straight
into the tail processing block if they are equal. This tail processing
block checks whether nbytes != 0, and does nothing otherwise.
However, in case of an allocation failure in the blkcipher layer, we
may enter this code with walk.nbytes == 0, while nbytes > 0. In this
case, we should not dereference the source and destination pointers,
since they may be NULL. So instead of checking for nbytes != 0, check
for (walk.nbytes % AES_BLOCK_SIZE) != 0, which implies the former in
non-error conditions.
Fixes: 86464859cc77 ("crypto: arm - AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions")
Cc: stable@vger.kernel.org
Reported-by: xiakaixu <xiakaixu@huawei.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Pull KVM fixes from Paolo Bonzini:
- s390: nested virt fixes (new 4.8 feature)
- x86: fixes for 4.8 regressions
- ARM: two small bugfixes
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
kvm-arm: Unmap shadow pagetables properly
x86, clock: Fix kvm guest tsc initialization
arm: KVM: Fix idmap overlap detection when the kernel is idmap'ed
KVM: lapic: adjust preemption timer correctly when goes TSC backward
KVM: s390: vsie: fix riccbd
KVM: s390: don't use current->thread.fpu.* when accessing registers
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Add the required PCMCIA clock for the SA1111 "1800" device. This clock
is used to compute timing information for the PCMCIA interface in the
SoC device, rather than the SA1111. Hence, the provision of this clock
is a convenience for the driver and does not reflect the hardware, so
this must not be copied into DT.
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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Accidentally booting Collie on Assabet reveals that the locomo driver
incorrectly overwrites gpio-sa1100's chip data for its parent interrupt,
leading to oops in sa1100_gpio_unmask() and sa1100_update_edge_regs()
when "gpio: sa1100: convert to use IO accessors" is applied. Fix locomo
to use the handler data rather than chip data for its parent interrupt.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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The cachepolicy variable gets initialized using a masked pmd
value. So far, the pmd has been masked with flags valid for the
2-page table format, but the 3-page table format requires a
different mask. On LPAE, this lead to a wrong assumption of what
initial cache policy has been used. Later a check forces the
cache policy to writealloc and prints the following warning:
Forcing write-allocate cache policy for SMP
This patch introduces a new definition PMD_SECT_CACHE_MASK for
both page table formats which masks in all cache flags in both
cases.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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SA1111 forgets to call clk_disable() in the probe error cleanup path.
Add the necessary call.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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SA1111 PCMCIA was broken when PCMCIA switched to using dev_pm_ops for
the PCMCIA socket class. PCMCIA used to handle suspend/resume via the
socket hosting device, which happened at normal device suspend/resume
time.
However, the referenced commit changed this: much of the resume now
happens much earlier, in the noirq resume handler of dev_pm_ops.
However, on SA1111, the PCMCIA device is not accessible as the SA1111
has not been resumed at _noirq time. It's slightly worse than that,
because the SA1111 has already been put to sleep at _noirq time, so
suspend doesn't work properly.
Fix this by converting the core SA1111 code to use dev_pm_ops as well,
and performing its own suspend/resume at noirq time.
This fixes these errors in the kernel log:
pcmcia_socket pcmcia_socket0: time out after reset
pcmcia_socket pcmcia_socket1: time out after reset
and the resulting lack of PCMCIA cards after a S2RAM cycle.
Fixes: d7646f7632549 ("pcmcia: use dev_pm_ops for class pcmcia_socket_class")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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The polarity of the high IRQs was being calculated using
SA1111_IRQMASK_HI(), but this assumes a Linux interrupt number, not a
hardware interrupt number. Hence, the resulting mask was incorrect.
Fix this.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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Ensure that we propagate the platform_get_irq() error code out of the
probe function. This allows probe deferrals to work correctly should
platform_get_irq() not be able to resolve the interrupt in a DT
environment at probe time.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
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The number of CPU feature keys is meant to map 1:1 to the number of CPU
feature flags defined in cputable.h, and the latter must fit in an
unsigned long.
In commit 4db7327194db ("powerpc: Add option to use jump label for
cpu_has_feature()"), I incorrectly defined NUM_CPU_FTR_KEYS to 64.
There should be no real adverse consequences of this bug, other than us
allocating too many keys.
Fix it by using BITS_PER_LONG.
Fixes: 4db7327194db ("powerpc: Add option to use jump label for cpu_has_feature()")
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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pnv_wakeup_tb_loss() currently expects cr4 to be "eq" if the CPU is
waking up from a complete hypervisor state loss. Hence, it currently
restores the SPR contents only if cr4 is "eq".
However, after commit bcef83a00dc4 ("powerpc/powernv: Add platform
support for stop instruction"), on ISA v3.0 CPUs, the function
pnv_restore_hyp_resource() sets cr4 to contain the result of the
comparison between the state the CPU has woken up from and the first
deep stop state before calling pnv_wakeup_tb_loss().
Thus if the CPU woke up from a state that is deeper than the first
deep stop state, cr4 will have "gt" set and hence, pnv_wakeup_tb_loss()
will fail to restore the SPRs on waking up from such a state.
Fix the code in pnv_wakeup_tb_loss() to restore the SPR states when cr4
is "eq" or "gt".
Fixes: bcef83a00dc4 ("powerpc/powernv: Add platform support for stop instruction")
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Shreyas B. Prabhu <shreyasbp@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm fixes from Dan Williams:
"nvdimm fixes for v4.8, two of them are tagged for -stable:
- Fix devm_memremap_pages() to use track_pfn_insert(). Otherwise,
DAX pmd mappings end up with an uncached pgprot, and unusable
performance for the device-dax interface. The device-dax interface
appeared in 4.7 so this is tagged for -stable.
- Fix a couple VM_BUG_ON() checks in the show_smaps() path to
understand DAX pmd entries. This fix is tagged for -stable.
- Fix a mis-merge of the nfit machine-check handler to flip the
polarity of an if() to match the final version of the patch that
Vishal sent for 4.8-rc1. Without this the nfit machine check
handler never detects / inserts new 'badblocks' entries which
applications use to identify lost portions of files.
- For test purposes, fix the nvdimm_clear_poison() path to operate on
legacy / simulated nvdimm memory ranges. Without this fix a test
can set badblocks, but never clear them on these ranges.
- Fix the range checking done by dax_dev_pmd_fault(). This is not
tagged for -stable since this problem is mitigated by specifying
aligned resources at device-dax setup time.
These patches have appeared in a next release over the past week. The
recent rebase you can see in the timestamps was to drop an invalid fix
as identified by the updated device-dax unit tests [1]. The -mm
touches have an ack from Andrew"
[1]: "[ndctl PATCH 0/3] device-dax test for recent kernel bugs"
https://lists.01.org/pipermail/linux-nvdimm/2016-September/006855.html
* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
libnvdimm: allow legacy (e820) pmem region to clear bad blocks
nfit, mce: Fix SPA matching logic in MCE handler
mm: fix cache mode of dax pmd mappings
mm: fix show_smap() for zone_device-pmd ranges
dax: fix mapping size check
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Alexander hit the WARN_ON_ONCE(!event) on his Skylake while running
the perf fuzzer.
This means the PEBSv3 record included a status bit for an inactive
event, something that _should_ not happen.
Move the code that filters the status bits against our known PEBS
events up a spot to guarantee we only deal with events we know about.
Further add "continue" statements to the WARN_ON_ONCE()s such that
we'll not die nor generate silly events in case we ever do hit them
again.
Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: stable@vger.kernel.org
Fixes: a3d86542de88 ("perf/x86/intel/pebs: Add PEBSv3 decoding")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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At the moment, intel_bts will WARN() out if there is more than one
event writing to the same ring buffer, via SET_OUTPUT, and will only
send data from one event to a buffer.
There is no reason to have this warning in, so kill it.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160906132353.19887-6-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Since BTS doesn't have a dedicated PMI status bit, the driver needs to
take extra care to check for the condition that triggers it to avoid
spurious NMI warnings.
Regardless of the local BTS context state, the only way of knowing that
the NMI is ours is to compare the write pointer against the interrupt
threshold.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160906132353.19887-5-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The intel_bts driver is using a CPU-local 'started' variable to order
callbacks and PMIs and make sure that AUX transactions don't get messed
up. However, the ordering rules in regard to this variable is a complete
mess, which recently resulted in perf_fuzzer-triggered warnings and
panics.
The general ordering rule that is patch is enforcing is that this
cpu-local variable be set only when the cpu-local AUX transaction is
active; consequently, this variable is to be checked before the AUX
related bits can be touched.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160906132353.19887-4-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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track_pfn_insert() in vmf_insert_pfn_pmd() is marking dax mappings as
uncacheable rendering them impractical for application usage. DAX-pte
mappings are cached and the goal of establishing DAX-pmd mappings is to
attain more performance, not dramatically less (3 orders of magnitude).
track_pfn_insert() relies on a previous call to reserve_memtype() to
establish the expected page_cache_mode for the range. While memremap()
arranges for reserve_memtype() to be called, devm_memremap_pages() does
not. So, teach track_pfn_insert() and untrack_pfn() how to handle
tracking without a vma, and arrange for devm_memremap_pages() to
establish the write-back-cache reservation in the memtype tree.
Cc: <stable@vger.kernel.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Nilesh Choudhury <nilesh.choudhury@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Toshi Kani <toshi.kani@hpe.com>
Reported-by: Kai Zhang <kai.ka.zhang@oracle.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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it should clear the destination even when access_ok() fails.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The resent conversion of the cpu hotplug support in the uncore driver
introduced a regression due to the way the callbacks are invoked at
initialization time.
The old code called the prepare/starting/online function on each online cpu
as a block. The new code registers the hotplug callbacks in the core for
each state. The core invokes the callbacks at each registration on all
online cpus.
The code implicitely relied on the prepare/starting/online callbacks being
called as combo on a particular cpu, which was not obvious and completely
undocumented.
The resulting subtle wreckage happens due to the way how the uncore code
manages shared data structures for cpus which share an uncore resource in
hardware. The sharing is determined in the cpu starting callback, but the
prepare callback allocates per cpu data for the upcoming cpu because
potential sharing is unknown at this point. If the starting callback finds
a online cpu which shares the hardware resource it takes a refcount on the
percpu data of that cpu and puts the own data structure into a
'free_at_online' pointer of that shared data structure. The online callback
frees that.
With the old model this worked because in a starting callback only one non
unused structure (the one of the starting cpu) was available. The new code
allocates the data structures for all cpus when the prepare callback is
registered.
Now the starting function iterates through all online cpus and looks for a
data structure (skipping its own) which has a matching hardware id. The id
member of the data structure is initialized to 0, but the hardware id can
be 0 as well. The resulting wreckage is:
CPU0 finds a matching id on CPU1, takes a refcount on CPU1 data and puts
its own data structure into CPU1s data structure to be freed.
CPU1 skips CPU0 because the data structure is its allegedly unsued own.
It finds a matching id on CPU2, takes a refcount on CPU1 data and puts
its own data structure into CPU2s data structure to be freed.
....
Now the online callbacks are invoked.
CPU0 has a pointer to CPU1s data and frees the original CPU0 data. So
far so good.
CPU1 has a pointer to CPU2s data and frees the original CPU1 data, which
is still referenced by CPU0 ---> Booom
So there are two issues to be solved here:
1) The id field must be initialized at allocation time to a value which
cannot be a valid hardware id, i.e. -1
This prevents the above scenario, but now CPU1 and CPU2 both stick their
own data structure into the free_at_online pointer of CPU0. So we leak
CPU1s data structure.
2) Fix the memory leak described in #1
Instead of having a single pointer, use a hlist to enqueue the
superflous data structures which are then freed by the first cpu
invoking the online callback.
Ideally we should know the sharing _before_ invoking the prepare callback,
but that's way beyond the scope of this bug fix.
[ tglx: Rewrote changelog ]
Fixes: 96b2bd3866a0 ("perf/x86/amd/uncore: Convert to hotplug state machine")
Reported-and-tested-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20160909160822.lowgmkdwms2dheyv@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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