syzbot


possible deadlock in iter_file_splice_write (4)

Status: closed as dup on 2024/06/05 11:05
Subsystems: overlayfs
[Documentation on labels]
Reported-by: syzbot+5ce16f43e888965f009d@syzkaller.appspotmail.com
First crash: 321d, last: 52d
Duplicate of
Title Repro Cause bisect Fix bisect Count Last Reported
possible deadlock in kernfs_seq_start kernfs C done 15 12d 355d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [overlayfs?] possible deadlock in iter_file_splice_write (4) 1 (2) 2024/06/05 11:05
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in iter_file_splice_write (3) overlayfs 24 357d 400d 0/28 closed as dup on 2024/03/14 09:27
upstream possible deadlock in iter_file_splice_write overlayfs 1 1689d 1685d 0/28 auto-closed as invalid on 2020/12/30 21:45
upstream possible deadlock in iter_file_splice_write (2) overlayfs C done 2 1363d 1359d 0/28 closed as dup on 2021/07/28 14:57
linux-5.15 possible deadlock in iter_file_splice_write (2) 1 2d13h 2d13h 0/3 upstream: reported on 2025/04/15 12:07
linux-5.15 possible deadlock in iter_file_splice_write 1 175d 175d 0/3 auto-obsoleted due to no activity on 2025/02/01 14:50

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc4-syzkaller #0 Not tainted
------------------------------------------------------
syz.7.1491/13055 is trying to acquire lock:
ffff88807baac868 (&pipe->mutex){+.+.}-{4:4}, at: iter_file_splice_write+0x330/0x1510 fs/splice.c:687

but task is already holding lock:
ffff88806664e420 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0xce4/0x18b0 fs/splice.c:1353

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (sb_writers#5){.+.+}-{0:0}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1785 [inline]
       sb_start_write include/linux/fs.h:1921 [inline]
       ovl_start_write+0x11d/0x290 fs/overlayfs/util.c:31
       ovl_do_copy_up fs/overlayfs/copy_up.c:990 [inline]
       ovl_copy_up_one fs/overlayfs/copy_up.c:1202 [inline]
       ovl_copy_up_flags+0x1145/0x47c0 fs/overlayfs/copy_up.c:1257
       ovl_nlink_start+0x9c/0x400 fs/overlayfs/util.c:1165
       ovl_do_remove+0x1fa/0xd90 fs/overlayfs/dir.c:920
       vfs_rmdir+0x3a5/0x510 fs/namei.c:4396
       do_rmdir+0x3b5/0x580 fs/namei.c:4455
       __do_sys_rmdir fs/namei.c:4474 [inline]
       __se_sys_rmdir fs/namei.c:4472 [inline]
       __x64_sys_rmdir+0x47/0x50 fs/namei.c:4472
       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 (&ovl_i_lock_key[depth]){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
       ovl_inode_lock_interruptible fs/overlayfs/overlayfs.h:650 [inline]
       ovl_copy_up_start+0x53/0x310 fs/overlayfs/util.c:727
       ovl_copy_up_one fs/overlayfs/copy_up.c:1195 [inline]
       ovl_copy_up_flags+0xcfe/0x47c0 fs/overlayfs/copy_up.c:1257
       ovl_nlink_start+0x9c/0x400 fs/overlayfs/util.c:1165
       ovl_do_remove+0x1fa/0xd90 fs/overlayfs/dir.c:920
       vfs_rmdir+0x3a5/0x510 fs/namei.c:4396
       do_rmdir+0x3b5/0x580 fs/namei.c:4455
       __do_sys_rmdir fs/namei.c:4474 [inline]
       __se_sys_rmdir fs/namei.c:4472 [inline]
       __x64_sys_rmdir+0x47/0x50 fs/namei.c:4472
       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 (&ovl_i_mutex_dir_key[depth]){++++}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       down_read+0xb1/0xa40 kernel/locking/rwsem.c:1524
       inode_lock_shared include/linux/fs.h:887 [inline]
       lookup_slow+0x45/0x70 fs/namei.c:1809
       walk_component+0x2e1/0x410 fs/namei.c:2114
       lookup_last fs/namei.c:2612 [inline]
       path_lookupat+0x16f/0x450 fs/namei.c:2636
       filename_lookup+0x2a3/0x670 fs/namei.c:2665
       kern_path+0x35/0x50 fs/namei.c:2773
       lookup_bdev+0xc5/0x290 block/bdev.c:1163
       resume_store+0x1a0/0x710 kernel/power/hibernate.c:1247
       kernfs_fop_write_iter+0x3a2/0x500 fs/kernfs/file.c:334
       new_sync_write fs/read_write.c:586 [inline]
       vfs_write+0xad1/0xd10 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 (&of->mutex){+.+.}-{4:4}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
       kernfs_fop_write_iter+0x1ea/0x500 fs/kernfs/file.c:325
       iter_file_splice_write+0xbfc/0x1510 fs/splice.c:743
       do_splice_from fs/splice.c:941 [inline]
       do_splice+0xd6a/0x18b0 fs/splice.c:1354
       __do_splice fs/splice.c:1436 [inline]
       __do_sys_splice fs/splice.c:1639 [inline]
       __se_sys_splice+0x2e0/0x450 fs/splice.c:1621
       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 (&pipe->mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
       iter_file_splice_write+0x330/0x1510 fs/splice.c:687
       do_splice_from fs/splice.c:941 [inline]
       do_splice+0xd6a/0x18b0 fs/splice.c:1354
       __do_splice fs/splice.c:1436 [inline]
       __do_sys_splice fs/splice.c:1639 [inline]
       __se_sys_splice+0x2e0/0x450 fs/splice.c:1621
       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:
  &pipe->mutex --> &ovl_i_lock_key[depth] --> sb_writers#5

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(sb_writers#5);
                               lock(&ovl_i_lock_key[depth]);
                               lock(sb_writers#5);
  lock(&pipe->mutex);

 *** DEADLOCK ***

1 lock held by syz.7.1491/13055:
 #0: ffff88806664e420 (sb_writers#5){.+.+}-{0:0}, at: do_splice+0xce4/0x18b0 fs/splice.c:1353

stack backtrace:
CPU: 1 UID: 0 PID: 13055 Comm: syz.7.1491 Not tainted 6.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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:2076
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
 iter_file_splice_write+0x330/0x1510 fs/splice.c:687
 do_splice_from fs/splice.c:941 [inline]
 do_splice+0xd6a/0x18b0 fs/splice.c:1354
 __do_splice fs/splice.c:1436 [inline]
 __do_sys_splice fs/splice.c:1639 [inline]
 __se_sys_splice+0x2e0/0x450 fs/splice.c:1621
 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: 0033:0x7f0290f8d169
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:00007f0291d5b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007f02911a6160 RCX: 00007f0290f8d169
RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f029100e2a0 R08: 0000000000000006 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f02911a6160 R15: 00007ffe5f45ef98
 </TASK>

Crashes (26):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/24 04:45 upstream d082ecbc71e9 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in iter_file_splice_write
2024/12/13 20:21 upstream f932fb9b4074 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/12/13 03:58 upstream 150b567e0d57 3547e30f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/11/25 07:56 upstream 9f16d5e6f220 68da6d95 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/11/23 08:26 upstream 06afb0f36106 68da6d95 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/11/23 08:18 upstream 06afb0f36106 68da6d95 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/11/14 19:33 upstream 0a9b9d17f3a7 77f3eeb7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/11/10 18:44 upstream de2f378f2b77 6b856513 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/11/04 05:20 upstream b9021de3ec2f f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/11/02 02:22 upstream 6c52d4da1c74 f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/09/12 20:31 upstream 77f587896757 60e1a995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/09/10 16:28 upstream bc83b4d1f086 86aa7bd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/09/10 16:16 upstream bc83b4d1f086 86aa7bd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/08/24 14:54 upstream d2bafcf224f3 d7d32352 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in iter_file_splice_write
2024/06/18 07:55 upstream 2ccbdf43d5e7 ce6011bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/06/17 02:29 upstream 2ccbdf43d5e7 f429ab00 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/06/06 03:36 upstream 2df0193e62cf 121701b6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/06/06 01:20 upstream 71d7b52cc33b 5aa1a7c9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/06/05 21:34 upstream 71d7b52cc33b 5aa1a7c9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/06/05 00:36 upstream 32f88d65f01b e1e2c66e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/06/04 00:37 upstream f06ce441457d a1feae05 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/06/03 16:09 upstream c3f38fa61af7 0aba2352 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/06/02 15:18 upstream 83814698cf48 3113787f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/05/31 22:40 upstream d8ec19857b09 3113787f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2024/05/31 18:46 upstream 4a4be1ad3a6e 0c378259 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in iter_file_splice_write
2025/02/23 07:01 linux-next e5d3fd687aac d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in iter_file_splice_write
* Struck through repros no longer work on HEAD.