kernel/linux.git/fs/pipe.c, branch v6.6.132

fs/pipe: Fix lockdep false-positive in watchqueue pipe_write()

2024-04-10T14:35:57+00:00

[ Upstream commit 055ca83559912f2cfd91c9441427bac4caf3c74e ] When you try to splice between a normal pipe and a notification pipe, get_pipe_info(..., true) fails, so splice() falls back to treating the notification pipe like a normal pipe - so we end up in iter_file_splice_write(), which first locks the input pipe, then calls vfs_iter_write(), which locks the output pipe. Lockdep complains about that, because we're taking a pipe lock while already holding another pipe lock. I think this probably (?) can't actually lead to deadlocks, since you'd need another way to nest locking a normal pipe into locking a watch_queue pipe, but the lockdep annotations don't make that clear. Bail out earlier in pipe_write() for notification pipes, before taking the pipe lock. Reported-and-tested-by: Closes: https://syzkaller.appspot.com/bug?extid=011e4ea1da6692cf881c Fixes: c73be61cede5 ("pipe: Add general notification queue support") Signed-off-by: Jann Horn Link: https://lore.kernel.org/r/20231124150822.2121798-1-jannh@google.com Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

pipe: wakeup wr_wait after setting max_usage

2024-02-01T00:19:09+00:00

[ Upstream commit e95aada4cb93d42e25c30a0ef9eb2923d9711d4a ] Commit c73be61cede5 ("pipe: Add general notification queue support") a regression was introduced that would lock up resized pipes under certain conditions. See the reproducer in [1]. The commit resizing the pipe ring size was moved to a different function, doing that moved the wakeup for pipe->wr_wait before actually raising pipe->max_usage. If a pipe was full before the resize occured it would result in the wakeup never actually triggering pipe_write. Set @max_usage and @nr_accounted before waking writers if this isn't a watch queue. Link: https://bugzilla.kernel.org/show_bug.cgi?id=212295 [1] Link: https://lore.kernel.org/r/20231201-orchideen-modewelt-e009de4562c6@brauner Fixes: c73be61cede5 ("pipe: Add general notification queue support") Reviewed-by: David Howells Cc: Signed-off-by: Lukas Schauer [Christian Brauner : rewrite to account for watch queues] Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

fs/pipe: move check to pipe_has_watch_queue()

2024-02-01T00:19:09+00:00

[ Upstream commit b4bd6b4bac8edd61eb8f7b836969d12c0c6af165 ] This declutters the code by reducing the number of #ifdefs and makes the watch_queue checks simpler. This has no runtime effect; the machine code is identical. Signed-off-by: Max Kellermann Message-Id: <20230921075755.1378787-2-max.kellermann@ionos.com> Reviewed-by: David Howells Signed-off-by: Christian Brauner Stable-dep-of: e95aada4cb93 ("pipe: wakeup wr_wait after setting max_usage") Signed-off-by: Sasha Levin

fs/pipe: remove duplicate "offset" initializer

2023-09-20T12:22:01+00:00

This code duplication was introduced by commit a194dfe6e6f6 ("pipe: Rearrange sequence in pipe_write() to preallocate slot"), but since the pipe's mutex is locked, nobody else can modify the value meanwhile. Signed-off-by: Max Kellermann Message-Id: <20230919074045.1066796-1-max.kellermann@ionos.com> Signed-off-by: Christian Brauner

Merge tag 'v6.6-vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2023-08-28T17:17:14+00:00

Pull misc vfs updates from Christian Brauner: "This contains the usual miscellaneous features, cleanups, and fixes for vfs and individual filesystems. Features: - Block mode changes on symlinks and rectify our broken semantics - Report file modifications via fsnotify() for splice - Allow specifying an explicit timeout for the "rootwait" kernel command line option. This allows to timeout and reboot instead of always waiting indefinitely for the root device to show up - Use synchronous fput for the close system call Cleanups: - Get rid of open-coded lockdep workarounds for async io submitters and replace it all with a single consolidated helper - Simplify epoll allocation helper - Convert simple_write_begin and simple_write_end to use a folio - Convert page_cache_pipe_buf_confirm() to use a folio - Simplify __range_close to avoid pointless locking - Disable per-cpu buffer head cache for isolated cpus - Port ecryptfs to kmap_local_page() api - Remove redundant initialization of pointer buf in pipe code - Unexport the d_genocide() function which is only used within core vfs - Replace printk(KERN_ERR) and WARN_ON() with WARN() Fixes: - Fix various kernel-doc issues - Fix refcount underflow for eventfds when used as EFD_SEMAPHORE - Fix a mainly theoretical issue in devpts - Check the return value of __getblk() in reiserfs - Fix a racy assert in i_readcount_dec - Fix integer conversion issues in various functions - Fix LSM security context handling during automounts that prevented NFS superblock sharing" * tag 'v6.6-vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (39 commits) cachefiles: use kiocb_{start,end}_write() helpers ovl: use kiocb_{start,end}_write() helpers aio: use kiocb_{start,end}_write() helpers io_uring: use kiocb_{start,end}_write() helpers fs: create kiocb_{start,end}_write() helpers fs: add kerneldoc to file_{start,end}_write() helpers io_uring: rename kiocb_end_write() local helper splice: Convert page_cache_pipe_buf_confirm() to use a folio libfs: Convert simple_write_begin and simple_write_end to use a folio fs/dcache: Replace printk and WARN_ON by WARN fs/pipe: remove redundant initialization of pointer buf fs: Fix kernel-doc warnings devpts: Fix kernel-doc warnings doc: idmappings: fix an error and rephrase a paragraph init: Add support for rootwait timeout parameter vfs: fix up the assert in i_readcount_dec fs: Fix one kernel-doc comment docs: filesystems: idmappings: clarify from where idmappings are taken fs/buffer.c: disable per-CPU buffer_head cache for isolated CPUs vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing ...

fs/pipe: remove redundant initialization of pointer buf

2023-08-19T11:36:18+00:00

The pointer buf is being initializated with a value that is never read, it is being re-assigned later on at the pointer where it is being used. The initialization is redundant and can be removed. Cleans up clang scan build warning: fs/pipe.c:492:24: warning: Value stored to 'buf' during its initialization is never read [deadcode.DeadStores] Signed-off-by: Colin Ian King Message-Id: <20230818144556.1208082-1-colin.i.king@gmail.com> Signed-off-by: Christian Brauner

fs: convert to ctime accessor functions

2023-07-13T08:28:04+00:00

In later patches, we're going to change how the inode's ctime field is used. Switch to using accessor functions instead of raw accesses of inode->i_ctime. Reviewed-by: Jan Kara Signed-off-by: Jeff Layton Message-Id: <20230705190309.579783-23-jlayton@kernel.org> Signed-off-by: Christian Brauner

pipe: Pass argument of pipe_fcntl as int

2023-07-10T12:36:12+00:00

The interface for fcntl expects the argument passed for the command F_SETPIPE_SZ to be of type int. The current code wrongly treats it as a long. In order to avoid access to undefined bits, we should explicitly cast the argument to int. Cc: Alexander Viro Cc: Christian Brauner Cc: Jeff Layton Cc: Chuck Lever Cc: Kevin Brodsky Cc: Vincenzo Frascino Cc: Szabolcs Nagy Cc: "Theodore Ts'o" Cc: David Laight Cc: Mark Rutland Cc: linux-fsdevel@vger.kernel.org Cc: linux-morello@op-lists.linaro.org Signed-off-by: Luca Vizzarro Message-Id: <20230414152459.816046-4-Luca.Vizzarro@arm.com> Signed-off-by: Christian Brauner

pipe: check for IOCB_NOWAIT alongside O_NONBLOCK

2023-05-12T15:17:27+00:00

Pipe reads or writes need to enable nonblocking attempts, if either O_NONBLOCK is set on the file, or IOCB_NOWAIT is set in the iocb being passed in. The latter isn't currently true, ensure we check for both before waiting on data or space. Fixes: afed6271f5b0 ("pipe: set FMODE_NOWAIT on pipes") Signed-off-by: Jens Axboe Message-Id: Signed-off-by: Christian Brauner

pipe: set FMODE_NOWAIT on pipes

2023-04-25T20:08:59+00:00

Pipes themselves do not hold the the pipe lock across IO, and hence are safe for RWF_NOWAIT/IOCB_NOWAIT usage. The "contract" for NOWAIT is really "should not do IO under this lock", not strictly that we cannot block or that the below code is in any way atomic. Pipes fulfil that criteria. Acked-by: Dave Chinner Reviewed-by: Christian Brauner Signed-off-by: Jens Axboe