Red Hat Bugzilla – Bug 1152813
lockdep splat: xfs + splice()
Last modified: 2016-07-19 08:13:30 EDT
I was using "atomic upgrade" which calls into libostree. Notably it uses splice() with a pipe. [14689.265161] ====================================================== [14689.265175] [ INFO: possible circular locking dependency detected ] [14689.265186] 3.18.0-0.rc0.git2.1.fc22.x86_64 #1 Not tainted [14689.265190] ------------------------------------------------------- [14689.265199] atomic/1144 is trying to acquire lock: [14689.265203] (&sb->s_type->i_mutex_key#13){+.+.+.}, at: [<ffffffffa01465ba>] xfs_file_buffered_aio_write.isra.10+0x7a/0x310 [xfs] [14689.265245] but task is already holding lock: [14689.265249] (&pipe->mutex/1){+.+.+.}, at: [<ffffffff8126937e>] pipe_lock+0x1e/0x20 [14689.265262] which lock already depends on the new lock. [14689.265268] the existing dependency chain (in reverse order) is: [14689.265287] -> #2 (&pipe->mutex/1){+.+.+.}: [14689.265296] [<ffffffff810ffde4>] lock_acquire+0xa4/0x1d0 [14689.265303] [<ffffffff8183e5b5>] mutex_lock_nested+0x85/0x440 [14689.265310] [<ffffffff8126937e>] pipe_lock+0x1e/0x20 [14689.265315] [<ffffffff8129836a>] splice_to_pipe+0x2a/0x260 [14689.265321] [<ffffffff81298b9f>] __generic_file_splice_read+0x57f/0x620 [14689.265328] [<ffffffff81298c7b>] generic_file_splice_read+0x3b/0x90 [14689.265334] [<ffffffffa0145b20>] xfs_file_splice_read+0xb0/0x1e0 [xfs] [14689.265350] [<ffffffff812976ac>] do_splice_to+0x6c/0x90 [14689.265356] [<ffffffff81299e7d>] SyS_splice+0x6dd/0x800 [14689.265362] [<ffffffff81842f69>] system_call_fastpath+0x16/0x1b [14689.265368] -> #1 (&(&ip->i_iolock)->mr_lock){++++++}: [14689.265424] [<ffffffff810ffde4>] lock_acquire+0xa4/0x1d0 [14689.265494] [<ffffffff810f87be>] down_write_nested+0x5e/0xc0 [14689.265553] [<ffffffffa0153529>] xfs_ilock+0xb9/0x1c0 [xfs] [14689.265629] [<ffffffffa01465c7>] xfs_file_buffered_aio_write.isra.10+0x87/0x310 [xfs] [14689.265693] [<ffffffffa01468da>] xfs_file_write_iter+0x8a/0x130 [xfs] [14689.265749] [<ffffffff8126019e>] new_sync_write+0x8e/0xd0 [14689.265811] [<ffffffff81260a3a>] vfs_write+0xba/0x200 [14689.265862] [<ffffffff812616ac>] SyS_write+0x5c/0xd0 [14689.265912] [<ffffffff81842f69>] system_call_fastpath+0x16/0x1b [14689.265963] -> #0 (&sb->s_type->i_mutex_key#13){+.+.+.}: [14689.266024] [<ffffffff810ff45e>] __lock_acquire+0x1b0e/0x1c10 [14689.266024] [<ffffffff810ffde4>] lock_acquire+0xa4/0x1d0 [14689.266024] [<ffffffff8183e5b5>] mutex_lock_nested+0x85/0x440 [14689.266024] [<ffffffffa01465ba>] xfs_file_buffered_aio_write.isra.10+0x7a/0x310 [xfs] [14689.266024] [<ffffffffa01468da>] xfs_file_write_iter+0x8a/0x130 [xfs] [14689.266024] [<ffffffff81297ffc>] iter_file_splice_write+0x2ec/0x4b0 [14689.266024] [<ffffffff81299b21>] SyS_splice+0x381/0x800 [14689.266024] [<ffffffff81842f69>] system_call_fastpath+0x16/0x1b [14689.266024] other info that might help us debug this: [14689.266024] Chain exists of: &sb->s_type->i_mutex_key#13 --> &(&ip->i_iolock)->mr_lock --> &pipe->mutex/1 [14689.266024] Possible unsafe locking scenario: [14689.266024] CPU0 CPU1 [14689.266024] ---- ---- [14689.266024] lock(&pipe->mutex/1); [14689.266024] lock(&(&ip->i_iolock)->mr_lock); [14689.266024] lock(&pipe->mutex/1); [14689.266024] lock(&sb->s_type->i_mutex_key#13); [14689.266024] *** DEADLOCK *** [14689.266024] 2 locks held by atomic/1144: [14689.266024] #0: (sb_writers#8){.+.+.+}, at: [<ffffffff81299f1f>] SyS_splice+0x77f/0x800 [14689.266024] #1: (&pipe->mutex/1){+.+.+.}, at: [<ffffffff8126937e>] pipe_lock+0x1e/0x20 [14689.266024] stack backtrace: [14689.266024] CPU: 0 PID: 1144 Comm: atomic Not tainted 3.18.0-0.rc0.git2.1.fc22.x86_64 #1 [14689.266024] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [14689.266024] 0000000000000000 00000000fd91796b ffff88003793bad0 ffffffff81838f3e [14689.266024] ffffffff82c03eb0 ffff88003793bb10 ffffffff81836b36 ffff88003793bb70 [14689.266024] ffff88003828a670 ffff880038289a40 0000000000000002 ffff880038289ab0 [14689.266024] Call Trace: [14689.266024] [<ffffffff81838f3e>] dump_stack+0x4d/0x66 [14689.266024] [<ffffffff81836b36>] print_circular_bug+0x201/0x20f [14689.266024] [<ffffffff810ff45e>] __lock_acquire+0x1b0e/0x1c10 [14689.266024] [<ffffffff8101c8c0>] ? dump_trace+0x170/0x350 [14689.266024] [<ffffffff810ffde4>] lock_acquire+0xa4/0x1d0 [14689.266024] [<ffffffffa01465ba>] ? xfs_file_buffered_aio_write.isra.10+0x7a/0x310 [xfs] [14689.266024] [<ffffffff8183e5b5>] mutex_lock_nested+0x85/0x440 [14689.266024] [<ffffffffa01465ba>] ? xfs_file_buffered_aio_write.isra.10+0x7a/0x310 [xfs] [14689.266024] [<ffffffffa01465ba>] ? xfs_file_buffered_aio_write.isra.10+0x7a/0x310 [xfs] [14689.266024] [<ffffffff810fd36c>] ? mark_held_locks+0x7c/0xb0 [14689.266024] [<ffffffffa01465ba>] xfs_file_buffered_aio_write.isra.10+0x7a/0x310 [xfs] [14689.266024] [<ffffffff8126937e>] ? pipe_lock+0x1e/0x20 [14689.266024] [<ffffffffa01468da>] xfs_file_write_iter+0x8a/0x130 [xfs] [14689.266024] [<ffffffff81297ffc>] iter_file_splice_write+0x2ec/0x4b0 [14689.266024] [<ffffffff81299b21>] SyS_splice+0x381/0x800 [14689.266024] [<ffffffff81842f69>] system_call_fastpath+0x16/0x1b
Reported upstream.
This bug appears to have been reported against 'rawhide' during the Fedora 22 development cycle. Changing version to '22'. More information and reason for this action is here: https://fedoraproject.org/wiki/Fedora_Program_Management/HouseKeeping/Fedora22
Fedora 22 changed to end-of-life (EOL) status on 2016-07-19. Fedora 22 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.