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possible deadlock in btrfs_search_slot (3)

Status: upstream: reported on 2024/12/01 19:56
Subsystems: btrfs
[Documentation on labels]
Reported-by: syzbot+7791482179507f327138@syzkaller.appspotmail.com
First crash: 23d, last: 1d00h
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [btrfs?] possible deadlock in btrfs_search_slot (3) 0 (1) 2024/12/01 19:56
▶ ▼ Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in btrfs_search_slot (2) btrfs C error 2 487d 483d 25/28 fixed on 2023/12/21 03:45
upstream possible deadlock in btrfs_search_slot btrfs C error done 188 500d 774d 23/28 fixed on 2023/08/10 11:21

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc3-syzkaller-00136-g8faabc041a00 #0 Not tainted
------------------------------------------------------
syz.9.907/11060 is trying to acquire lock:
ffff888067579b38 (btrfs-tree-00){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146

but task is already holding lock:
ffff888067579ef8 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #8 (btrfs-tree-01){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849
       down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649
       btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146
       btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline]
       btrfs_read_lock_root_node+0x3f/0xd0 fs/btrfs/locking.c:267
       btrfs_search_slot_get_root fs/btrfs/ctree.c:1790 [inline]
       btrfs_search_slot+0x4f4/0x3180 fs/btrfs/ctree.c:2116
       btrfs_insert_empty_items+0x9c/0x1a0 fs/btrfs/ctree.c:4354
       btrfs_create_new_inode+0xe27/0x1f60 fs/btrfs/inode.c:6344
       btrfs_create_common+0x1d4/0x2e0 fs/btrfs/inode.c:6578
       lookup_open fs/namei.c:3649 [inline]
       open_last_lookups fs/namei.c:3748 [inline]
       path_openat+0x1c05/0x3590 fs/namei.c:3984
       do_filp_open+0x27f/0x4e0 fs/namei.c:4014
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1402
       do_sys_open fs/open.c:1417 [inline]
       __do_sys_openat fs/open.c:1433 [inline]
       __se_sys_openat fs/open.c:1428 [inline]
       __x64_sys_openat+0x247/0x2a0 fs/open.c:1428
       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 (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_create_common+0x1b2/0x2e0 fs/btrfs/inode.c:6572
       lookup_open fs/namei.c:3649 [inline]
       open_last_lookups fs/namei.c:3748 [inline]
       path_openat+0x1c05/0x3590 fs/namei.c:3984
       do_filp_open+0x27f/0x4e0 fs/namei.c:4014
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1402
       do_sys_open fs/open.c:1417 [inline]
       __do_sys_openat fs/open.c:1433 [inline]
       __se_sys_openat fs/open.c:1428 [inline]
       __x64_sys_openat+0x247/0x2a0 fs/open.c:1428
       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 (btrfs_trans_num_writers){++++}-{0:0}:
       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
       percpu_up_read include/linux/percpu-rwsem.h:99 [inline]
       __sb_end_write include/linux/fs.h:1720 [inline]
       sb_end_intwrite+0x26/0x1c0 include/linux/fs.h:1837
       __btrfs_end_transaction+0x251/0x630 fs/btrfs/transaction.c:1068
       btrfs_dirty_inode+0x151/0x1a0 fs/btrfs/inode.c:6069
       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

-> #5 (&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_ioctl+0x1ad/0x9a0 kernel/trace/blktrace.c:740
       blkdev_ioctl+0x40c/0x6a0 block/ioctl.c:682
       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

-> #4 (&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

-> #3 (&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

-> #2 (&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

-> #1 (&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:763 [inline]
       btrfs_submit_bbio+0xf91/0x19c0 fs/btrfs/bio.c:792
       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

-> #0 (btrfs-tree-00){++++}-{4:4}:
       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
       down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649
       btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146
       btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline]
       btrfs_search_slot+0x13c4/0x3180 fs/btrfs/ctree.c:2264
       btrfs_lookup_file_extent+0x14c/0x210 fs/btrfs/file-item.c:267
       run_delalloc_nocow+0x350/0x11e0 fs/btrfs/inode.c:2022
       btrfs_run_delalloc_range+0x3bf/0xff0 fs/btrfs/inode.c:2290
       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+0x53/0xe0 fs/btrfs/file.c:3720
       btrfs_direct_write+0x554/0xa30 fs/btrfs/direct-io.c:961
       btrfs_do_write_iter+0x2a0/0x760 fs/btrfs/file.c:1397
       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

other info that might help us debug this:

Chain exists of:
  btrfs-tree-00 --> btrfs_trans_num_extwriters --> btrfs-tree-01

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(btrfs-tree-01);
                               lock(btrfs_trans_num_extwriters);
                               lock(btrfs-tree-01);
  rlock(btrfs-tree-00);

 *** DEADLOCK ***

3 locks held by syz.9.907/11060:
 #0: ffff888060fd22b8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x254/0x320 fs/file.c:1191
 #1: ffff88803ce48420 (sb_writers#22){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2964 [inline]
 #1: ffff88803ce48420 (sb_writers#22){.+.+}-{0:0}, at: vfs_write+0x225/0xd30 fs/read_write.c:675
 #2: ffff888067579ef8 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146

stack backtrace:
CPU: 0 UID: 0 PID: 11060 Comm: syz.9.907 Not tainted 6.13.0-rc3-syzkaller-00136-g8faabc041a00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
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
 down_read_nested+0xb5/0xa50 kernel/locking/rwsem.c:1649
 btrfs_tree_read_lock_nested+0x2f/0x250 fs/btrfs/locking.c:146
 btrfs_tree_read_lock fs/btrfs/locking.h:188 [inline]
 btrfs_search_slot+0x13c4/0x3180 fs/btrfs/ctree.c:2264
 btrfs_lookup_file_extent+0x14c/0x210 fs/btrfs/file-item.c:267
 run_delalloc_nocow+0x350/0x11e0 fs/btrfs/inode.c:2022
 btrfs_run_delalloc_range+0x3bf/0xff0 fs/btrfs/inode.c:2290
 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+0x53/0xe0 fs/btrfs/file.c:3720
 btrfs_direct_write+0x554/0xa30 fs/btrfs/direct-io.c:961
 btrfs_do_write_iter+0x2a0/0x760 fs/btrfs/file.c:1397
 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
RIP: 0033:0x7f5b6bf85d29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5b6cdd1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5b6c175fa0 RCX: 00007f5b6bf85d29
RDX: 0000000000000020 RSI: 0000000020000080 RDI: 0000000000000005
RBP: 00007f5b6c001aa8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5b6c175fa0 R15: 00007ffdf720f4e8
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/20 13:32 upstream 8faabc041a00 1d58202c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in btrfs_search_slot
2024/11/27 19:52 upstream aaf20f870da0 5df23865 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in btrfs_search_slot
* Struck through repros no longer work on HEAD.