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2019-01-29cifs: limit amount of data we request for xattrs to CIFSMaxBufSizeRonnie Sahlberg
minus the various headers and blobs that will be part of the reply. or else we might trigger a session reconnect. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-01-29cifs: fix computation for MAX_SMB2_HDR_SIZERonnie Sahlberg
The size of the fixed part of the create response is 88 bytes not 56. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-01-29NFS: Fix up return value on fatal errors in nfs_page_async_flush()Trond Myklebust
Ensure that we return the fatal error value that caused us to exit nfs_page_async_flush(). Fixes: c373fff7bd25 ("NFSv4: Don't special case "launder"") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: stable@vger.kernel.org # v4.12+ Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-01-29debugfs: return error values, not NULLGreg Kroah-Hartman
When an error happens, debugfs should return an error pointer value, not NULL. This will prevent the totally theoretical error where a debugfs call fails due to lack of memory, returning NULL, and that dentry value is then passed to another debugfs call, which would end up succeeding, creating a file at the root of the debugfs tree, but would then be impossible to remove (because you can not remove the directory NULL). So, to make everyone happy, always return errors, this makes the users of debugfs much simpler (they do not have to ever check the return value), and everyone can rest easy. Reported-by: Gary R Hook <ghook@amd.com> Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reported-by: Masami Hiramatsu <mhiramat@kernel.org> Reported-by: Michal Hocko <mhocko@kernel.org> Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reported-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-28nfs: Fix NULL pointer dereference of dev_nameYao Liu
There is a NULL pointer dereference of dev_name in nfs_parse_devname() The oops looks something like: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 ... RIP: 0010:nfs_fs_mount+0x3b6/0xc20 [nfs] ... Call Trace: ? ida_alloc_range+0x34b/0x3d0 ? nfs_clone_super+0x80/0x80 [nfs] ? nfs_free_parsed_mount_data+0x60/0x60 [nfs] mount_fs+0x52/0x170 ? __init_waitqueue_head+0x3b/0x50 vfs_kern_mount+0x6b/0x170 do_mount+0x216/0xdc0 ksys_mount+0x83/0xd0 __x64_sys_mount+0x25/0x30 do_syscall_64+0x65/0x220 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fix this by adding a NULL check on dev_name Signed-off-by: Yao Liu <yotta.liu@ucloud.cn> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-01-28btrfs: don't end the transaction for delayed refs in throttleJosef Bacik
Previously callers to btrfs_end_transaction_throttle() would commit the transaction if there wasn't enough delayed refs space. This happens in relocation, and if the fs is relatively empty we'll run out of delayed refs space basically immediately, so we'll just be stuck in this loop of committing the transaction over and over again. This code existed because we didn't have a good feedback mechanism for running delayed refs, but with the delayed refs rsv we do now. Delete this throttling code and let the btrfs_start_transaction() in relocation deal with putting pressure on the delayed refs infrastructure. With this patch we no longer take 5 minutes to balance a metadata only fs. Qu has submitted a fstest to catch slow balance or excessive transaction commits. Steps to reproduce: * create subvolume * create many (eg. 16000) inlined files, of size 2KiB * iteratively snapshot and touch several files to trigger metadata updates * start balance -m Reported-by: Qu Wenruo <wqu@suse.com> Fixes: 64403612b73a ("btrfs: rework btrfs_check_space_for_delayed_refs") Signed-off-by: Josef Bacik <josef@toxicpanda.com> [ add tags and steps to reproduce ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-28Btrfs: fix deadlock when allocating tree block during leaf/node splitFilipe Manana
When splitting a leaf or node from one of the trees that are modified when flushing pending block groups (extent, chunk, device and free space trees), we need to allocate a new tree block, which in turn can result in the need to allocate a new block group. After allocating the new block group we may need to flush new block groups that were previously allocated during the course of the current transaction, which is what may cause a deadlock due to attempts to write lock twice the same leaf or node, as when splitting a leaf or node we are holding a write lock on it and its parent node. The same type of deadlock can also happen when increasing the tree's height, since we are holding a lock on the existing root while allocating the tree block to use as the new root node. An example trace when the deadlock happens during the leaf split path is: [27175.293054] CPU: 0 PID: 3005 Comm: kworker/u17:6 Tainted: G W 4.19.16 #1 [27175.293942] Hardware name: Penguin Computing Relion 1900/MD90-FS0-ZB-XX, BIOS R15 06/25/2018 [27175.294846] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs] (...) [27175.298384] RSP: 0018:ffffab2087107758 EFLAGS: 00010246 [27175.299269] RAX: 0000000000000bbd RBX: ffff9fadc7141c48 RCX: 0000000000000001 [27175.300155] RDX: 0000000000000001 RSI: 0000000000000002 RDI: ffff9fadc7141c48 [27175.301023] RBP: 0000000000000001 R08: ffff9faeb6ac1040 R09: ffff9fa9c0000000 [27175.301887] R10: 0000000000000000 R11: 0000000000000040 R12: ffff9fb21aac8000 [27175.302743] R13: ffff9fb1a64d6a20 R14: 0000000000000001 R15: ffff9fb1a64d6a18 [27175.303601] FS: 0000000000000000(0000) GS:ffff9fb21fa00000(0000) knlGS:0000000000000000 [27175.304468] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [27175.305339] CR2: 00007fdc8743ead8 CR3: 0000000763e0a006 CR4: 00000000003606f0 [27175.306220] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [27175.307087] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [27175.307940] Call Trace: [27175.308802] btrfs_search_slot+0x779/0x9a0 [btrfs] [27175.309669] ? update_space_info+0xba/0xe0 [btrfs] [27175.310534] btrfs_insert_empty_items+0x67/0xc0 [btrfs] [27175.311397] btrfs_insert_item+0x60/0xd0 [btrfs] [27175.312253] btrfs_create_pending_block_groups+0xee/0x210 [btrfs] [27175.313116] do_chunk_alloc+0x25f/0x300 [btrfs] [27175.313984] find_free_extent+0x706/0x10d0 [btrfs] [27175.314855] btrfs_reserve_extent+0x9b/0x1d0 [btrfs] [27175.315707] btrfs_alloc_tree_block+0x100/0x5b0 [btrfs] [27175.316548] split_leaf+0x130/0x610 [btrfs] [27175.317390] btrfs_search_slot+0x94d/0x9a0 [btrfs] [27175.318235] btrfs_insert_empty_items+0x67/0xc0 [btrfs] [27175.319087] alloc_reserved_file_extent+0x84/0x2c0 [btrfs] [27175.319938] __btrfs_run_delayed_refs+0x596/0x1150 [btrfs] [27175.320792] btrfs_run_delayed_refs+0xed/0x1b0 [btrfs] [27175.321643] delayed_ref_async_start+0x81/0x90 [btrfs] [27175.322491] normal_work_helper+0xd0/0x320 [btrfs] [27175.323328] ? move_linked_works+0x6e/0xa0 [27175.324160] process_one_work+0x191/0x370 [27175.324976] worker_thread+0x4f/0x3b0 [27175.325763] kthread+0xf8/0x130 [27175.326531] ? rescuer_thread+0x320/0x320 [27175.327284] ? kthread_create_worker_on_cpu+0x50/0x50 [27175.328027] ret_from_fork+0x35/0x40 [27175.328741] ---[ end trace 300a1b9f0ac30e26 ]--- Fix this by preventing the flushing of new blocks groups when splitting a leaf/node and when inserting a new root node for one of the trees modified by the flushing operation, similar to what is done when COWing a node/leaf from on of these trees. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202383 Reported-by: Eli V <eliventer@gmail.com> CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-27iomap: fix a use after free in iomap_dio_rwChristoph Hellwig
Introduce a local wait_for_completion variable to avoid an access to the potentially freed dio struture after dropping the last reference count. Also use the chance to document the completion behavior to make the refcounting clear to the reader of the code. Fixes: ff6a9292e6 ("iomap: implement direct I/O") Reported-by: Chandan Rajendra <chandan@linux.ibm.com> Reported-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Chandan Rajendra <chandan@linux.ibm.com> Tested-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-01-27iomap: get/put the page in iomap_page_create/release()Piotr Jaroszynski
migrate_page_move_mapping() expects pages with private data set to have a page_count elevated by 1. This is what used to happen for xfs through the buffer_heads code before the switch to iomap in commit 82cb14175e7d ("xfs: add support for sub-pagesize writeback without buffer_heads"). Not having the count elevated causes move_pages() to fail on memory mapped files coming from xfs. Make iomap compatible with the migrate_page_move_mapping() assumption by elevating the page count as part of iomap_page_create() and lowering it in iomap_page_release(). It causes the move_pages() syscall to misbehave on memory mapped files from xfs. It does not not move any pages, which I suppose is "just" a perf issue, but it also ends up returning a positive number which is out of spec for the syscall. Talking to Michal Hocko, it sounds like returning positive numbers might be a necessary update to move_pages() anyway though. Fixes: 82cb14175e7d ("xfs: add support for sub-pagesize writeback without buffer_heads") Signed-off-by: Piotr Jaroszynski <pjaroszynski@nvidia.com> [hch: actually get/put the page iomap_migrate_page() to make it work properly] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-01-26Merge tag '5.0-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6Linus Torvalds
Pull smb3 fixes from Steve French: "A set of small smb3 fixes, some fixing various crediting issues discovered during xfstest runs, five for stable" * tag '5.0-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: print CIFSMaxBufSize as part of /proc/fs/cifs/DebugData smb3: add credits we receive from oplock/break PDUs CIFS: Fix mounts if the client is low on credits CIFS: Do not assume one credit for async responses CIFS: Fix credit calculations in compound mid callback CIFS: Fix credit calculation for encrypted reads with errors CIFS: Fix credits calculations for reads with errors CIFS: Do not reconnect TCP session in add_credits() smb3: Cleanup license mess CIFS: Fix possible hang during async MTU reads and writes cifs: fix memory leak of an allocated cifs_ntsd structure
2019-01-26Merge tag 'for-linus-20190125' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block fixes from Jens Axboe: "A collection of fixes for this release. This contains: - Silence sparse rightfully complaining about non-static wbt functions (Bart) - Fixes for the zoned comments/ioctl documentation (Damien) - direct-io fix that's been lingering for a while (Ernesto) - cgroup writeback fix (Tejun) - Set of NVMe patches for nvme-rdma/tcp (Sagi, Hannes, Raju) - Block recursion tracking fix (Ming) - Fix debugfs command flag naming for a few flags (Jianchao)" * tag 'for-linus-20190125' of git://git.kernel.dk/linux-block: block: Fix comment typo uapi: fix ioctl documentation blk-wbt: Declare local functions static blk-mq: fix the cmd_flag_name array nvme-multipath: drop optimization for static ANA group IDs nvmet-rdma: fix null dereference under heavy load nvme-rdma: rework queue maps handling nvme-tcp: fix timeout handler nvme-rdma: fix timeout handler writeback: synchronize sync(2) against cgroup writeback membership switches block: cover another queue enter recursion via BIO_QUEUE_ENTERED direct-io: allow direct writes to empty inodes
2019-01-25debugfs: fix debugfs_rename parameter checkingGreg Kroah-Hartman
debugfs_rename() needs to check that the dentries passed into it really are valid, as sometimes they are not (i.e. if the return value of another debugfs call is passed into this one.) So fix this up by properly checking if the two parent directories are errors (they are allowed to be NULL), and if the dentry to rename is not NULL or an error. Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-25crypto: clarify name of WEAK_KEY request flagEric Biggers
CRYPTO_TFM_REQ_WEAK_KEY confuses newcomers to the crypto API because it sounds like it is requesting a weak key. Actually, it is requesting that weak keys be forbidden (for algorithms that have the notion of "weak keys"; currently only DES and XTS do). Also it is only one letter away from CRYPTO_TFM_RES_WEAK_KEY, with which it can be easily confused. (This in fact happened in the UX500 driver, though just in some debugging messages.) Therefore, make the intent clear by renaming it to CRYPTO_TFM_REQ_FORBID_WEAK_KEYS. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-01-24cifs: print CIFSMaxBufSize as part of /proc/fs/cifs/DebugDataRonnie Sahlberg
Was helpful in debug for some recent problems. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24smb3: add credits we receive from oplock/break PDUsRonnie Sahlberg
Otherwise we gradually leak credits leading to potential hung session. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> CC: Stable <stable@vger.kernel.org> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24CIFS: Fix mounts if the client is low on creditsPavel Shilovsky
If the server doesn't grant us at least 3 credits during the mount we won't be able to complete it because query path info operation requires 3 credits. Use the cached file handle if possible to allow the mount to succeed. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24CIFS: Do not assume one credit for async responsesPavel Shilovsky
If we don't receive a response we can't assume that the server granted one credit. Assume zero credits in such cases. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24CIFS: Fix credit calculations in compound mid callbackPavel Shilovsky
The current code doesn't do proper accounting for credits in SMB1 case: it adds one credit per response only if we get a complete response while it needs to return it unconditionally. Fix this and also include malformed responses for SMB2+ into accounting for credits because such responses have Credit Granted field, thus nothing prevents to get a proper credit value from them. Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24CIFS: Fix credit calculation for encrypted reads with errorsPavel Shilovsky
We do need to account for credits received in error responses to read requests on encrypted sessions. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24CIFS: Fix credits calculations for reads with errorsPavel Shilovsky
Currently we mark MID as malformed if we get an error from server in a read response. This leads to not properly processing credits in the readv callback. Fix this by marking such a response as normal received response and process it appropriately. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24CIFS: Do not reconnect TCP session in add_credits()Pavel Shilovsky
When executing add_credits() we currently call cifs_reconnect() if the number of credits is zero and there are no requests in flight. In this case we may call cifs_reconnect() recursively twice and cause memory corruption given the following sequence of functions: mid1.callback() -> add_credits() -> cifs_reconnect() -> -> mid2.callback() -> add_credits() -> cifs_reconnect(). Fix this by avoiding to call cifs_reconnect() in add_credits() and checking for zero credits in the demultiplex thread. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-25Merge tag 'fsnotify_for_v5.0-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull inotify fix from Jan Kara: "Fix a file refcount leak in an inotify error path" * tag 'fsnotify_for_v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: inotify: Fix fd refcount leak in inotify_add_watch().
2019-01-24smb3: Cleanup license messThomas Gleixner
Precise and non-ambiguous license information is important. The recently added aegis header file has a SPDX license identifier, which is nice, but at the same time it has a contradictionary license boiler plate text. SPDX-License-Identifier: GPL-2.0 versus * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. Oh well. Assuming that the SPDX identifier is correct and according to x86/hyper-v contributions from Microsoft GPL V2 only is the usual license. Remove the boiler plate as it is wrong and even if correct it is redundant. Fixes: eccb4422cf97 ("smb3: Add ftrace tracepoints for improved SMB3 debugging") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Steve French <sfrench@samba.org> Cc: linux-cifs@vger.kernel.org Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24CIFS: Fix possible hang during async MTU reads and writesPavel Shilovsky
When doing MTU i/o we need to leave some credits for possible reopen requests and other operations happening in parallel. Currently we leave 1 credit which is not enough even for reopen only: we need at least 2 credits if durable handle reconnect fails. Also there may be other operations at the same time including compounding ones which require 3 credits at a time each. Fix this by leaving 8 credits which is big enough to cover most scenarios. Was able to reproduce this when server was configured to give out fewer credits than usual. The proper fix would be to reconnect a file handle first and then obtain credits for an MTU request but this leads to bigger code changes and should happen in other patches. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-24cifs: fix memory leak of an allocated cifs_ntsd structureColin Ian King
The call to SMB2_queary_acl can allocate memory to pntsd and also return a failure via a call to SMB2_query_acl (and then query_info). This occurs when query_info allocates the structure and then in query_info the call to smb2_validate_and_copy_iov fails. Currently the failure just returns without kfree'ing pntsd hence causing a memory leak. Currently, *data is allocated if it's not already pointing to a buffer, so it needs to be kfree'd only if was allocated in query_info, so the fix adds an allocated flag to track this. Also set *dlen to zero on an error just to be safe since *data is kfree'd. Also set errno to -ENOMEM if the allocation of *data fails. Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Dan Carpener <dan.carpenter@oracle.com>
2019-01-22writeback: synchronize sync(2) against cgroup writeback membership switchesTejun Heo
sync_inodes_sb() can race against cgwb (cgroup writeback) membership switches and fail to writeback some inodes. For example, if an inode switches to another wb while sync_inodes_sb() is in progress, the new wb might not be visible to bdi_split_work_to_wbs() at all or the inode might jump from a wb which hasn't issued writebacks yet to one which already has. This patch adds backing_dev_info->wb_switch_rwsem to synchronize cgwb switch path against sync_inodes_sb() so that sync_inodes_sb() is guaranteed to see all the target wbs and inodes can't jump wbs to escape syncing. v2: Fixed misplaced rwsem init. Spotted by Jiufei. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jiufei Xue <xuejiufei@gmail.com> Link: http://lkml.kernel.org/r/dc694ae2-f07f-61e1-7097-7c8411cee12d@gmail.com Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-01-22direct-io: allow direct writes to empty inodesErnesto A. Fernández
On a DIO_SKIP_HOLES filesystem, the ->get_block() method is currently not allowed to create blocks for an empty inode. This confusion comes from trying to bit shift a negative number, so check the size of the inode first. The problem is most visible for hfsplus, because the fallback to buffered I/O doesn't happen and the write fails with EIO. This is in part the fault of the module, because it gives a wrong return value on ->get_block(); that will be fixed in a separate patch. Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-01-21ceph: quota: cleanup license messThomas Gleixner
Precise and non-ambiguous license information is important. The recently added quota.c file has a SPDX license identifier, which is nice, but at the same time it has a contradictionary license boiler plate text. SPDX-License-Identifier: GPL-2.0 versus * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. Oh well. As the other ceph related files are licensed under the GPL v2 only, it's assumed that the SPDX id is correct and the boiler plate was randomly copied into that patch. Remove the boiler plate as it is wrong and even if correct it is redundant. Fixes: fb18a57568c2 ("ceph: quota: add initial infrastructure to support cephfs quotas") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Luis Henriques <lhenriques@suse.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: "Yan, Zheng" <zyan@redhat.com> Cc: Sage Weil <sage@redhat.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: ceph-devel@vger.kernel.org Acked-by: Luis Henriques <lhenriques@suse.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2019-01-21ceph: clear inode pointer when snap realm gets dropped by its inodeYan, Zheng
snap realm and corresponding inode have pointers to each other. The two pointer should get clear at the same time. Otherwise, snap realm's pointer may reference freed inode. Cc: stable@vger.kernel.org # 4.17+ Signed-off-by: "Yan, Zheng" <zyan@redhat.com> Reviewed-by: Luis Henriques <lhenriques@suse.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2019-01-21Merge tag 'pstore-v5.0-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull pstore fixes from Kees Cook: - Fix console ramoops to show the previous boot logs (Sai Prakash Ranjan) - Avoid allocation and leak of platform data * tag 'pstore-v5.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: pstore/ram: Avoid allocation and leak of platform data pstore/ram: Fix console ramoops to show the previous boot logs
2019-01-20pstore/ram: Avoid allocation and leak of platform dataKees Cook
Yue Hu noticed that when parsing device tree the allocated platform data was never freed. Since it's not used beyond the function scope, this switches to using a stack variable instead. Reported-by: Yue Hu <huyue2@yulong.com> Fixes: 35da60941e44 ("pstore/ram: add Device Tree bindings") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-21Merge tag 'for-5.0-rc2-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: "A handful of fixes (some of them in testing for a long time): - fix some test failures regarding cleanup after transaction abort - revert of a patch that could cause a deadlock - delayed iput fixes, that can help in ENOSPC situation when there's low space and a lot data to write" * tag 'for-5.0-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: wakeup cleaner thread when adding delayed iput btrfs: run delayed iputs before committing btrfs: wait on ordered extents on abort cleanup btrfs: handle delayed ref head accounting cleanup in abort Revert "btrfs: balance dirty metadata pages in btrfs_finish_ordered_io"
2019-01-20Merge tag 'nfs-for-5.0-2' of git://git.linux-nfs.org/projects/anna/linux-nfsLinus Torvalds
Pull NFS client fixes from Anna Schumaker: "These are mostly fixes for SUNRPC bugs, with a single v4.2 copy_file_range() fix mixed in. Stable bugfixes: - Fix TCP receive code on archs with flush_dcache_page() Other bugfixes: - Fix error code in rpcrdma_buffer_create() - Fix a double free in rpcrdma_send_ctxs_create() - Fix kernel BUG at kernel/cred.c:825 - Fix unnecessary retry in nfs42_proc_copy_file_range() - Ensure rq_bytes_sent is reset before request transmission - Ensure we respect the RPCSEC_GSS sequence number limit - Address Kerberos performance/behavior regression" * tag 'nfs-for-5.0-2' of git://git.linux-nfs.org/projects/anna/linux-nfs: SUNRPC: Address Kerberos performance/behavior regression SUNRPC: Ensure we respect the RPCSEC_GSS sequence number limit SUNRPC: Ensure rq_bytes_sent is reset before request transmission NFSv4.2 fix unnecessary retry in nfs4_copy_file_range sunrpc: kernel BUG at kernel/cred.c:825! SUNRPC: Fix TCP receive code on archs with flush_dcache_page() xprtrdma: Double free in rpcrdma_sendctxs_create() xprtrdma: Fix error code in rpcrdma_buffer_create()
2019-01-20Merge tag 'for-linus-20190118' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block fixes from Jens Axboe: - block size setting fixes for loop/nbd (Jan Kara) - md bio_alloc_mddev() cleanup (Marcos) - Ensure we don't lose the REQ_INTEGRITY flag (Ming) - Two NVMe fixes by way of Christoph: - Fix NVMe IRQ calculation (Ming) - Uninitialized variable in nvmet-tcp (Sagi) - BFQ comment fix (Paolo) - License cleanup for recently added blk-mq-debugfs-zoned (Thomas) * tag 'for-linus-20190118' of git://git.kernel.dk/linux-block: block: Cleanup license notice nvme-pci: fix nvme_setup_irqs() nvmet-tcp: fix uninitialized variable access block: don't lose track of REQ_INTEGRITY flag blockdev: Fix livelocks on loop device nbd: Use set_blocksize() to set device blocksize md: Make bio_alloc_mddev use bio_alloc_bioset block, bfq: fix comments on __bfq_deactivate_entity
2019-01-18btrfs: wakeup cleaner thread when adding delayed iputJosef Bacik
The cleaner thread usually takes care of delayed iputs, with the exception of the btrfs_end_transaction_throttle path. Delaying iputs means we are potentially delaying the eviction of an inode and it's respective space. The cleaner thread only gets woken up every 30 seconds, or when we require space. If there are a lot of inodes that need to be deleted we could induce a serious amount of latency while we wait for these inodes to be evicted. So instead wakeup the cleaner if it's not already awake to process any new delayed iputs we add to the list. If we suddenly need space we will less likely be backed up behind a bunch of inodes that are waiting to be deleted, and we could possibly free space before we need to get into the flushing logic which will save us some latency. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-18btrfs: run delayed iputs before committingJosef Bacik
Delayed iputs means we can have final iputs of deleted inodes in the queue, which could potentially generate a lot of pinned space that could be free'd. So before we decide to commit the transaction for ENOPSC reasons, run the delayed iputs so that any potential space is free'd up. If there is and we freed enough we can then commit the transaction and potentially be able to make our reservation. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-18btrfs: wait on ordered extents on abort cleanupJosef Bacik
If we flip read-only before we initiate writeback on all dirty pages for ordered extents we've created then we'll have ordered extents left over on umount, which results in all sorts of bad things happening. Fix this by making sure we wait on ordered extents if we have to do the aborted transaction cleanup stuff. generic/475 can produce this warning: [ 8531.177332] WARNING: CPU: 2 PID: 11997 at fs/btrfs/disk-io.c:3856 btrfs_free_fs_root+0x95/0xa0 [btrfs] [ 8531.183282] CPU: 2 PID: 11997 Comm: umount Tainted: G W 5.0.0-rc1-default+ #394 [ 8531.185164] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),BIOS rel-1.11.2-0-gf9626cc-prebuilt.qemu-project.org 04/01/2014 [ 8531.187851] RIP: 0010:btrfs_free_fs_root+0x95/0xa0 [btrfs] [ 8531.193082] RSP: 0018:ffffb1ab86163d98 EFLAGS: 00010286 [ 8531.194198] RAX: ffff9f3449494d18 RBX: ffff9f34a2695000 RCX:0000000000000000 [ 8531.195629] RDX: 0000000000000002 RSI: 0000000000000001 RDI:0000000000000000 [ 8531.197315] RBP: ffff9f344e930000 R08: 0000000000000001 R09:0000000000000000 [ 8531.199095] R10: 0000000000000000 R11: ffff9f34494d4ff8 R12:ffffb1ab86163dc0 [ 8531.200870] R13: ffff9f344e9300b0 R14: ffffb1ab86163db8 R15:0000000000000000 [ 8531.202707] FS: 00007fc68e949fc0(0000) GS:ffff9f34bd800000(0000)knlGS:0000000000000000 [ 8531.204851] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 8531.205942] CR2: 00007ffde8114dd8 CR3: 000000002dfbd000 CR4:00000000000006e0 [ 8531.207516] Call Trace: [ 8531.208175] btrfs_free_fs_roots+0xdb/0x170 [btrfs] [ 8531.210209] ? wait_for_completion+0x5b/0x190 [ 8531.211303] close_ctree+0x157/0x350 [btrfs] [ 8531.212412] generic_shutdown_super+0x64/0x100 [ 8531.213485] kill_anon_super+0x14/0x30 [ 8531.214430] btrfs_kill_super+0x12/0xa0 [btrfs] [ 8531.215539] deactivate_locked_super+0x29/0x60 [ 8531.216633] cleanup_mnt+0x3b/0x70 [ 8531.217497] task_work_run+0x98/0xc0 [ 8531.218397] exit_to_usermode_loop+0x83/0x90 [ 8531.219324] do_syscall_64+0x15b/0x180 [ 8531.220192] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 8531.221286] RIP: 0033:0x7fc68e5e4d07 [ 8531.225621] RSP: 002b:00007ffde8116608 EFLAGS: 00000246 ORIG_RAX:00000000000000a6 [ 8531.227512] RAX: 0000000000000000 RBX: 00005580c2175970 RCX:00007fc68e5e4d07 [ 8531.229098] RDX: 0000000000000001 RSI: 0000000000000000 RDI:00005580c2175b80 [ 8531.230730] RBP: 0000000000000000 R08: 00005580c2175ba0 R09:00007ffde8114e80 [ 8531.232269] R10: 0000000000000000 R11: 0000000000000246 R12:00005580c2175b80 [ 8531.233839] R13: 00007fc68eac61c4 R14: 00005580c2175a68 R15:0000000000000000 Leaving a tree in the rb-tree: 3853 void btrfs_free_fs_root(struct btrfs_root *root) 3854 { 3855 iput(root->ino_cache_inode); 3856 WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree)); CC: stable@vger.kernel.org Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> [ add stacktrace ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-18btrfs: handle delayed ref head accounting cleanup in abortJosef Bacik
We weren't doing any of the accounting cleanup when we aborted transactions. Fix this by making cleanup_ref_head_accounting global and calling it from the abort code, this fixes the issue where our accounting was all wrong after the fs aborts. The test generic/475 on a 2G VM can trigger the problems eg.: [ 8502.136957] WARNING: CPU: 0 PID: 11064 at fs/btrfs/extent-tree.c:5986 btrfs_free_block_grou +ps+0x3dc/0x410 [btrfs] [ 8502.148372] CPU: 0 PID: 11064 Comm: umount Not tainted 5.0.0-rc1-default+ #394 [ 8502.150807] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626 +cc-prebuilt.qemu-project.org 04/01/2014 [ 8502.154317] RIP: 0010:btrfs_free_block_groups+0x3dc/0x410 [btrfs] [ 8502.160623] RSP: 0018:ffffb1ab84b93de8 EFLAGS: 00010206 [ 8502.161906] RAX: 0000000001000000 RBX: ffff9f34b1756400 RCX: 0000000000000000 [ 8502.163448] RDX: 0000000000000002 RSI: 0000000000000001 RDI: ffff9f34b1755400 [ 8502.164906] RBP: ffff9f34b7e8c000 R08: 0000000000000001 R09: 0000000000000000 [ 8502.166716] R10: 0000000000000000 R11: 0000000000000001 R12: ffff9f34b7e8c108 [ 8502.168498] R13: ffff9f34b7e8c158 R14: 0000000000000000 R15: dead000000000100 [ 8502.170296] FS: 00007fb1cf15ffc0(0000) GS:ffff9f34bd400000(0000) knlGS:0000000000000000 [ 8502.172439] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 8502.173669] CR2: 00007fb1ced507b0 CR3: 000000002f7a6000 CR4: 00000000000006f0 [ 8502.175094] Call Trace: [ 8502.175759] close_ctree+0x17f/0x350 [btrfs] [ 8502.176721] generic_shutdown_super+0x64/0x100 [ 8502.177702] kill_anon_super+0x14/0x30 [ 8502.178607] btrfs_kill_super+0x12/0xa0 [btrfs] [ 8502.179602] deactivate_locked_super+0x29/0x60 [ 8502.180595] cleanup_mnt+0x3b/0x70 [ 8502.181406] task_work_run+0x98/0xc0 [ 8502.182255] exit_to_usermode_loop+0x83/0x90 [ 8502.183113] do_syscall_64+0x15b/0x180 [ 8502.183919] entry_SYSCALL_64_after_hwframe+0x49/0xbe Corresponding to release_global_block_rsv() { ... WARN_ON(fs_info->delayed_refs_rsv.reserved > 0); CC: stable@vger.kernel.org Signed-off-by: Josef Bacik <josef@toxicpanda.com> [ add log dump ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-18Revert "btrfs: balance dirty metadata pages in btrfs_finish_ordered_io"David Sterba
This reverts commit e73e81b6d0114d4a303205a952ab2e87c44bd279. This patch causes a few problems: - adds latency to btrfs_finish_ordered_io - as btrfs_finish_ordered_io is used for free space cache, generating more work from btrfs_btree_balance_dirty_nodelay could end up in the same workque, effectively deadlocking 12260 kworker/u96:16+btrfs-freespace-write D [<0>] balance_dirty_pages+0x6e6/0x7ad [<0>] balance_dirty_pages_ratelimited+0x6bb/0xa90 [<0>] btrfs_finish_ordered_io+0x3da/0x770 [<0>] normal_work_helper+0x1c5/0x5a0 [<0>] process_one_work+0x1ee/0x5a0 [<0>] worker_thread+0x46/0x3d0 [<0>] kthread+0xf5/0x130 [<0>] ret_from_fork+0x24/0x30 [<0>] 0xffffffffffffffff Transaction commit will wait on the freespace cache: 838 btrfs-transacti D [<0>] btrfs_start_ordered_extent+0x154/0x1e0 [<0>] btrfs_wait_ordered_range+0xbd/0x110 [<0>] __btrfs_wait_cache_io+0x49/0x1a0 [<0>] btrfs_write_dirty_block_groups+0x10b/0x3b0 [<0>] commit_cowonly_roots+0x215/0x2b0 [<0>] btrfs_commit_transaction+0x37e/0x910 [<0>] transaction_kthread+0x14d/0x180 [<0>] kthread+0xf5/0x130 [<0>] ret_from_fork+0x24/0x30 [<0>] 0xffffffffffffffff And then writepages ends up waiting on transaction commit: 9520 kworker/u96:13+flush-btrfs-1 D [<0>] wait_current_trans+0xac/0xe0 [<0>] start_transaction+0x21b/0x4b0 [<0>] cow_file_range_inline+0x10b/0x6b0 [<0>] cow_file_range.isra.69+0x329/0x4a0 [<0>] run_delalloc_range+0x105/0x3c0 [<0>] writepage_delalloc+0x119/0x180 [<0>] __extent_writepage+0x10c/0x390 [<0>] extent_write_cache_pages+0x26f/0x3d0 [<0>] extent_writepages+0x4f/0x80 [<0>] do_writepages+0x17/0x60 [<0>] __writeback_single_inode+0x59/0x690 [<0>] writeback_sb_inodes+0x291/0x4e0 [<0>] __writeback_inodes_wb+0x87/0xb0 [<0>] wb_writeback+0x3bb/0x500 [<0>] wb_workfn+0x40d/0x610 [<0>] process_one_work+0x1ee/0x5a0 [<0>] worker_thread+0x1e0/0x3d0 [<0>] kthread+0xf5/0x130 [<0>] ret_from_fork+0x24/0x30 [<0>] 0xffffffffffffffff Eventually, we have every process in the system waiting on balance_dirty_pages(), and nobody is able to make progress on page writeback. The original patch tried to fix an OOM condition, that happened on 4.4 but no success reproducing that on later kernels (4.19 and 4.20). This is more likely a problem in OOM itself. Link: https://lore.kernel.org/linux-btrfs/20180528054821.9092-1-ethanlien@synology.com/ Reported-by: Chris Mason <clm@fb.com> CC: stable@vger.kernel.org # 4.18+ CC: ethanlien <ethanlien@synology.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-01-18Merge tag 'afs-fixes-20190117' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull AFS fixes from David Howells: "Here's a set of fixes for AFS: - Use struct_size() for kzalloc() size calculation. - When calling YFS.CreateFile rather than AFS.CreateFile, it is possible to create a file with a file lock already held. The default value indicating no lock required is actually -1, not 0. - Fix an oops in inode/vnode validation if the target inode doesn't have a server interest assigned (ie. a server that will notify us of changes by third parties). - Fix refcounting of keys in file locking. - Fix a race in refcounting asynchronous operations in the event of an error during request transmission. The provision of a dedicated function to get an extra ref on a call is split into a separate commit" * tag 'afs-fixes-20190117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Fix race in async call refcounting afs: Provide a function to get a ref on a call afs: Fix key refcounting in file locking code afs: Don't set vnode->cb_s_break in afs_validate() afs: Set correct lock type for the yfs CreateFile afs: Use struct_size() in kzalloc()
2019-01-17pstore/ram: Fix console ramoops to show the previous boot logsSai Prakash Ranjan
commit b05c950698fe ("pstore/ram: Simplify ramoops_get_next_prz() arguments") changed update assignment in getting next persistent ram zone by adding a check for record type. But the check always returns true since the record type is assigned 0. And this breaks console ramoops by showing current console log instead of previous log on warm reset and hard reset (actually hard reset should not be showing any logs). Fix this by having persistent ram zone type check instead of record type check. Tested this on SDM845 MTP and dragonboard 410c. Reproducing this issue is simple as below: 1. Trigger hard reset and mount pstore. Will see console-ramoops record in the mounted location which is the current log. 2. Trigger warm reset and mount pstore. Will see the current console-ramoops record instead of previous record. Fixes: b05c950698fe ("pstore/ram: Simplify ramoops_get_next_prz() arguments") Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org> [kees: dropped local variable usage] Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-17fix cgroup_do_mount() handling of failure exitsAl Viro
same story as with last May fixes in sysfs (7b745a4e4051 "unfuck sysfs_mount()"); new_sb is left uninitialized in case of early errors in kernfs_mount_ns() and papering over it by treating any error from kernfs_mount_ns() as equivalent to !new_ns ends up conflating the cases when objects had never been transferred to a superblock with ones when that has happened and resulting new superblock had been dropped. Easily fixed (same way as in sysfs case). Additionally, there's a superblock leak on kernfs_node_dentry() failure *and* a dentry leak inside kernfs_node_dentry() itself - the latter on probably impossible errors, but the former not impossible to trigger (as the matter of fact, injecting allocation failures at that point *does* trigger it). Cc: stable@kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-01-17afs: Fix race in async call refcountingDavid Howells
There's a race between afs_make_call() and afs_wake_up_async_call() in the case that an error is returned from rxrpc_kernel_send_data() after it has queued the final packet. afs_make_call() will try and clean up the mess, but the call state may have been moved on thereby causing afs_process_async_call() to also try and to delete the call. Fix this by: (1) Getting an extra ref for an asynchronous call for the call itself to hold. This makes sure the call doesn't evaporate on us accidentally and will allow the call to be retained by the caller in a future patch. The ref is released on leaving afs_make_call() or afs_wait_for_call_to_complete(). (2) In the event of an error from rxrpc_kernel_send_data(): (a) Don't set the call state to AFS_CALL_COMPLETE until *after* the call has been aborted and ended. This prevents afs_deliver_to_call() from doing anything with any notifications it gets. (b) Explicitly end the call immediately to prevent further callbacks. (c) Cancel any queued async_work and wait for the work if it's executing. This allows us to be sure the race won't recur when we change the state. We put the work queue's ref on the call if we managed to cancel it. (d) Put the call's ref that we got in (1). This belongs to us as long as the call is in state AFS_CALL_CL_REQUESTING. Fixes: 341f741f04be ("afs: Refcount the afs_call struct") Signed-off-by: David Howells <dhowells@redhat.com>
2019-01-17afs: Provide a function to get a ref on a callDavid Howells
Provide a function to get a reference on an afs_call struct. Signed-off-by: David Howells <dhowells@redhat.com>
2019-01-17afs: Fix key refcounting in file locking codeDavid Howells
Fix the refcounting of the authentication keys in the file locking code. The vnode->lock_key member points to a key on which it expects to be holding a ref, but it isn't always given an extra ref, however. Fixes: 0fafdc9f888b ("afs: Fix file locking") Signed-off-by: David Howells <dhowells@redhat.com>
2019-01-17afs: Don't set vnode->cb_s_break in afs_validate()Marc Dionne
A cb_interest record is not necessarily attached to the vnode on entry to afs_validate(), which can cause an oops when we try to bring the vnode's cb_s_break up to date in the default case (ie. no current callback promise and the vnode has not been deleted). Fix this by simply removing the line, as vnode->cb_s_break will be set when needed by afs_register_server_cb_interest() when we next get a callback promise from RPC call. The oops looks something like: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 ... RIP: 0010:afs_validate+0x66/0x250 [kafs] ... Call Trace: afs_d_revalidate+0x8d/0x340 [kafs] ? __d_lookup+0x61/0x150 lookup_dcache+0x44/0x70 ? lookup_dcache+0x44/0x70 __lookup_hash+0x24/0xa0 do_unlinkat+0x11d/0x2c0 __x64_sys_unlink+0x23/0x30 do_syscall_64+0x4d/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: ae3b7361dc0e ("afs: Fix validation/callback interaction") Signed-off-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com>
2019-01-16fuse: decrement NR_WRITEBACK_TEMP on the right pageMiklos Szeredi
NR_WRITEBACK_TEMP is accounted on the temporary page in the request, not the page cache page. Fixes: 8b284dc47291 ("fuse: writepages: handle same page rewrites") Cc: <stable@vger.kernel.org> # v3.13 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-01-16fuse: call pipe_buf_release() under pipe lockJann Horn
Some of the pipe_buf_release() handlers seem to assume that the pipe is locked - in particular, anon_pipe_buf_release() accesses pipe->tmp_page without taking any extra locks. From a glance through the callers of pipe_buf_release(), it looks like FUSE is the only one that calls pipe_buf_release() without having the pipe locked. This bug should only lead to a memory leak, nothing terrible. Fixes: dd3bb14f44a6 ("fuse: support splice() writing to fuse device") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-01-16cuse: fix ioctlMiklos Szeredi
cuse_process_init_reply() doesn't initialize fc->max_pages and thus all cuse bases ioctls fail with ENOMEM. Reported-by: Andreas Steinmetz <ast@domdv.de> Fixes: 5da784cce430 ("fuse: add max_pages to init_out") Cc: <stable@vger.kernel.org> # v4.20 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-01-16fuse: handle zero sized retrieve correctlyMiklos Szeredi
Dereferencing req->page_descs[0] will Oops if req->max_pages is zero. Reported-by: syzbot+c1e36d30ee3416289cc0@syzkaller.appspotmail.com Tested-by: syzbot+c1e36d30ee3416289cc0@syzkaller.appspotmail.com Fixes: b2430d7567a3 ("fuse: add per-page descriptor <offset, length> to fuse_req") Cc: <stable@vger.kernel.org> # v3.9 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>