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possible deadlock in join_transaction (2)

Status: upstream: reported on 2024/12/09 02:08
Subsystems: btrfs
[Documentation on labels]
Reported-by: syzbot+77cf6638a2a1806ef852@syzkaller.appspotmail.com
First crash: 16d, last: 4d15h
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [btrfs?] possible deadlock in join_transaction (2) 0 (1) 2024/12/09 02:08
▶ ▼ Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in join_transaction btrfs 23 180d 223d 0/28 auto-obsoleted due to no activity on 2024/09/01 23:05

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc3-syzkaller #0 Not tainted
------------------------------------------------------
kworker/u8:17/22022 is trying to acquire lock:
ffff88806ab0e470
 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x405/0xda0 fs/btrfs/transaction.c:288

but task is already holding lock:
ffff888052768610 (sb_internal#3){.+.+}-{0:0}, at: __cow_file_range_inline+0x160/0x1140 fs/btrfs/inode.c:666

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #8 (sb_internal#3){.+.+}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1725 [inline]
       sb_start_intwrite include/linux/fs.h:1908 [inline]
       start_transaction+0x8fd/0x1670 fs/btrfs/transaction.c:691
       btrfs_dirty_inode+0xa5/0x1a0 fs/btrfs/inode.c:6055
       inode_update_time fs/inode.c:2124 [inline]
       touch_atime+0x27f/0x690 fs/inode.c:2197
       file_accessed include/linux/fs.h:2539 [inline]
       btrfs_file_mmap+0xbd/0x120 fs/btrfs/file.c:1954
       call_mmap include/linux/fs.h:2183 [inline]
       mmap_file mm/internal.h:124 [inline]
       __mmap_new_file_vma mm/vma.c:2291 [inline]
       __mmap_new_vma mm/vma.c:2355 [inline]
       __mmap_region+0x2206/0x2cd0 mm/vma.c:2456
       mmap_region+0x1d0/0x2c0 mm/mmap.c:1348
       do_mmap+0x8f0/0x1000 mm/mmap.c:496
       vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:580
       ksys_mmap_pgoff+0x4eb/0x720 mm/mmap.c:542
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #7 (&mm->mmap_lock){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __might_fault+0xc6/0x120 mm/memory.c:6751
       _inline_copy_from_user include/linux/uaccess.h:162 [inline]
       _copy_from_user+0x2a/0xc0 lib/usercopy.c:18
       copy_from_user include/linux/uaccess.h:212 [inline]
       __blk_trace_setup kernel/trace/blktrace.c:626 [inline]
       blk_trace_setup+0xd2/0x1e0 kernel/trace/blktrace.c:648
       sg_ioctl_common drivers/scsi/sg.c:1114 [inline]
       sg_ioctl+0xa46/0x2e80 drivers/scsi/sg.c:1156
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (&q->debugfs_mutex){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       blk_mq_init_sched+0x3fa/0x830 block/blk-mq-sched.c:473
       elevator_init_mq+0x20e/0x320 block/elevator.c:610
       add_disk_fwnode+0x10d/0xf80 block/genhd.c:413
       sd_probe+0xba6/0x1100 drivers/scsi/sd.c:4024
       really_probe+0x2ba/0xad0 drivers/base/dd.c:658
       __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
       driver_probe_device+0x50/0x430 drivers/base/dd.c:830
       __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
       bus_for_each_drv+0x250/0x2e0 drivers/base/bus.c:459
       __device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987
       async_run_entry_fn+0xaa/0x420 kernel/async.c:129
       process_one_work kernel/workqueue.c:3229 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310
       worker_thread+0x870/0xd30 kernel/workqueue.c:3391
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #5 (&q->q_usage_counter(queue)#50){++++}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       blk_queue_enter+0xe1/0x600 block/blk-core.c:328
       blk_mq_alloc_request+0x4fa/0xaa0 block/blk-mq.c:652
       scsi_alloc_request drivers/scsi/scsi_lib.c:1222 [inline]
       scsi_execute_cmd+0x177/0x1090 drivers/scsi/scsi_lib.c:304
       read_capacity_16+0x2b4/0x1450 drivers/scsi/sd.c:2655
       sd_read_capacity drivers/scsi/sd.c:2824 [inline]
       sd_revalidate_disk+0x1013/0xbce0 drivers/scsi/sd.c:3734
       sd_probe+0x9fa/0x1100 drivers/scsi/sd.c:4010
       really_probe+0x2ba/0xad0 drivers/base/dd.c:658
       __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
       driver_probe_device+0x50/0x430 drivers/base/dd.c:830
       __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
       bus_for_each_drv+0x250/0x2e0 drivers/base/bus.c:459
       __device_attach_async_helper+0x22d/0x300 drivers/base/dd.c:987
       async_run_entry_fn+0xaa/0x420 kernel/async.c:129
       process_one_work kernel/workqueue.c:3229 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310
       worker_thread+0x870/0xd30 kernel/workqueue.c:3391
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #4 (&q->limits_lock){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x1ac/0xee0 kernel/locking/mutex.c:735
       queue_limits_start_update include/linux/blkdev.h:947 [inline]
       loop_reconfigure_limits+0x43f/0x900 drivers/block/loop.c:998
       loop_set_block_size drivers/block/loop.c:1473 [inline]
       lo_simple_ioctl drivers/block/loop.c:1496 [inline]
       lo_ioctl+0x1351/0x1f50 drivers/block/loop.c:1559
       blkdev_ioctl+0x57f/0x6a0 block/ioctl.c:693
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&q->q_usage_counter(io)#24){++++}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       bio_queue_enter block/blk.h:75 [inline]
       blk_mq_submit_bio+0x1536/0x2390 block/blk-mq.c:3090
       __submit_bio+0x2c6/0x560 block/blk-core.c:629
       __submit_bio_noacct_mq block/blk-core.c:710 [inline]
       submit_bio_noacct_nocheck+0x4d3/0xe30 block/blk-core.c:739
       btrfs_submit_chunk fs/btrfs/bio.c:757 [inline]
       btrfs_submit_bbio+0xef7/0x1980 fs/btrfs/bio.c:786
       read_extent_buffer_pages+0x61f/0x7f0 fs/btrfs/extent_io.c:3558
       btrfs_read_extent_buffer+0xdb/0x730 fs/btrfs/disk-io.c:229
       read_block_for_search+0x79e/0xbb0 fs/btrfs/ctree.c:1619
       btrfs_search_slot+0x1274/0x3180 fs/btrfs/ctree.c:2240
       btrfs_init_root_free_objectid+0x148/0x330 fs/btrfs/disk-io.c:4846
       btrfs_init_fs_root fs/btrfs/disk-io.c:1137 [inline]
       btrfs_get_root_ref+0x5d7/0xc30 fs/btrfs/disk-io.c:1364
       btrfs_get_fs_root fs/btrfs/disk-io.c:1416 [inline]
       open_ctree+0x2470/0x2a30 fs/btrfs/disk-io.c:3532
       btrfs_fill_super fs/btrfs/super.c:972 [inline]
       btrfs_get_tree_super fs/btrfs/super.c:1898 [inline]
       btrfs_get_tree+0x12d8/0x1a30 fs/btrfs/super.c:2093
       vfs_get_tree+0x92/0x2b0 fs/super.c:1814
       fc_mount+0x1b/0xb0 fs/namespace.c:1231
       btrfs_get_tree_subvol fs/btrfs/super.c:2051 [inline]
       btrfs_get_tree+0x6b1/0x1a30 fs/btrfs/super.c:2094
       vfs_get_tree+0x92/0x2b0 fs/super.c:1814
       do_new_mount+0x2be/0xb40 fs/namespace.c:3507
       do_mount fs/namespace.c:3847 [inline]
       __do_sys_mount fs/namespace.c:4057 [inline]
       __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (btrfs-tree-00){++++}-{4:4}:
       reacquire_held_locks+0x3eb/0x690 kernel/locking/lockdep.c:5374
       __lock_release kernel/locking/lockdep.c:5563 [inline]
       lock_release+0x396/0xa30 kernel/locking/lockdep.c:5870
       up_read+0x16/0x20 kernel/locking/rwsem.c:1619
       btrfs_tree_unlock_rw fs/btrfs/locking.h:213 [inline]
       unlock_up+0x3c5/0x820 fs/btrfs/ctree.c:1489
       btrfs_next_old_leaf+0x1a40/0x1bd0 fs/btrfs/ctree.c:5038
       btrfs_next_leaf fs/btrfs/ctree.h:717 [inline]
       btrfs_drop_extents+0x9a4/0x33e0 fs/btrfs/file.c:249
       __cow_file_range_inline+0x2e9/0x1140 fs/btrfs/inode.c:679
       cow_file_range_inline+0x317/0x3d0 fs/btrfs/inode.c:738
       cow_file_range+0x39e/0x11f0 fs/btrfs/inode.c:1357
       btrfs_run_delalloc_range+0x722/0xff0 fs/btrfs/inode.c:2303
       writepage_delalloc+0x9b9/0xd50 fs/btrfs/extent_io.c:1239
       extent_writepage fs/btrfs/extent_io.c:1499 [inline]
       extent_write_cache_pages fs/btrfs/extent_io.c:2194 [inline]
       btrfs_writepages+0x1389/0x20e0 fs/btrfs/extent_io.c:2325
       do_writepages+0x361/0x880 mm/page-writeback.c:2702
       filemap_fdatawrite_wbc mm/filemap.c:397 [inline]
       __filemap_fdatawrite_range mm/filemap.c:430 [inline]
       filemap_fdatawrite_range+0x215/0x2c0 mm/filemap.c:448
       btrfs_fdatawrite_range fs/btrfs/file.c:3720 [inline]
       start_ordered_ops fs/btrfs/file.c:1455 [inline]
       btrfs_sync_file+0x3c4/0x11e0 fs/btrfs/file.c:1537
       generic_write_sync include/linux/fs.h:2904 [inline]
       btrfs_do_write_iter+0x5e0/0x760 fs/btrfs/file.c:1407
       new_sync_write fs/read_write.c:586 [inline]
       vfs_write+0xaed/0xd30 fs/read_write.c:679
       ksys_write+0x18f/0x2b0 fs/read_write.c:731
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (btrfs_trans_num_extwriters){++++}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       join_transaction+0x19c/0xda0 fs/btrfs/transaction.c:313
       start_transaction+0xaf8/0x1670 fs/btrfs/transaction.c:697
       btrfs_ioctl_subvol_setflags+0x46a/0x760 fs/btrfs/ioctl.c:1515
       btrfs_ioctl+0x8ea/0xcc0 fs/btrfs/ioctl.c:5194
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:906 [inline]
       __se_sys_ioctl+0xf7/0x170 fs/ioctl.c:892
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (btrfs_trans_num_writers){++++}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       join_transaction+0x424/0xda0 fs/btrfs/transaction.c:288
       start_transaction+0xaf8/0x1670 fs/btrfs/transaction.c:697
       __cow_file_range_inline+0x160/0x1140 fs/btrfs/inode.c:666
       cow_file_range_inline+0x317/0x3d0 fs/btrfs/inode.c:738
       compress_file_range+0xc1f/0x1410
       btrfs_work_helper+0x392/0xc40 fs/btrfs/async-thread.c:314
       process_one_work kernel/workqueue.c:3229 [inline]
       process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310
       worker_thread+0x870/0xd30 kernel/workqueue.c:3391
       kthread+0x2f2/0x390 kernel/kthread.c:389
       ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Chain exists of:
  btrfs_trans_num_writers --> &mm->mmap_lock --> sb_internal#3

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_internal#3);
                               lock(&mm->mmap_lock);
                               lock(sb_internal#3);
  rlock(btrfs_trans_num_writers);

 *** DEADLOCK ***

3 locks held by kworker/u8:17/22022:
 #0: ffff88806e4a4948 ((wq_completion)btrfs-delalloc){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88806e4a4948 ((wq_completion)btrfs-delalloc){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310
 #1: ffffc9000bf2fd00 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000bf2fd00 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310
 #2: ffff888052768610 (sb_internal#3){.+.+}-{0:0}, at: __cow_file_range_inline+0x160/0x1140 fs/btrfs/inode.c:666

stack backtrace:
CPU: 0 UID: 0 PID: 22022 Comm: kworker/u8:17 Not tainted 6.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
Workqueue: btrfs-delalloc btrfs_work_helper
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3904
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5226
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
 join_transaction+0x424/0xda0 fs/btrfs/transaction.c:288
 start_transaction+0xaf8/0x1670 fs/btrfs/transaction.c:697
 __cow_file_range_inline+0x160/0x1140 fs/btrfs/inode.c:666
 cow_file_range_inline+0x317/0x3d0 fs/btrfs/inode.c:738
 compress_file_range+0xc1f/0x1410
 btrfs_work_helper+0x392/0xc40 fs/btrfs/async-thread.c:314
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa68/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/16 23:02 upstream 78d4f34e2115 f93b2b55 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in join_transaction
2024/12/14 22:43 upstream a0e3919a2df2 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in join_transaction
2024/12/09 08:41 upstream 62b5a46999c7 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in join_transaction
2024/12/05 01:59 upstream feffde684ac2 29f61fce .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root possible deadlock in join_transaction
* Struck through repros no longer work on HEAD.