syzbot


WARNING: bad unlock balance in seq_read_iter

Status: upstream: reported C repro on 2025/01/31 20:47
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+c041985778e4069e1ce3@syzkaller.appspotmail.com
First crash: 112d, last: 2d10h
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] tracing: keep the event lock balanced 1 (1) 2025/02/01 05:50
[syzbot] [fs?] WARNING: bad unlock balance in seq_read_iter 4 (8) 2025/02/01 05:50
Last patch testing requests (5)
Created Duration User Patch Repo Result
2025/02/01 05:30 19m eadavis@qq.com patch upstream OK log
2025/02/01 03:44 19m eadavis@qq.com https://github.com/ea1davis/linux ftr/syz OK log
2025/02/01 02:27 19m eadavis@qq.com https://github.com/ea1davis/linux ftr/syz OK log
2025/02/01 01:42 19m eadavis@qq.com https://github.com/ea1davis/linux ftr/syz OK log
2025/02/01 01:04 19m eadavis@qq.com https://github.com/ea1davis/linux ftr/syz OK log

Sample crash report:
RSP: 002b:00007ffd4c5723b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007ffd4c5723c0 RCX: 00007f790ac9d2e9
RDX: 0000000000000080 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffd4c572157 R09: 00007f790ad00032
R10: 0000000000000001 R11: 0000000000000246 R12: 00007f790ad08618
R13: 00007ffd4c572598 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
=====================================
WARNING: bad unlock balance detected!
6.15.0-rc6-syzkaller #0 Not tainted
-------------------------------------
syz-executor342/5826 is trying to release lock (event_mutex) at:
[<ffffffff823cda8d>] seq_read_iter+0x60d/0x12c0 fs/seq_file.c:251
but there are no more locks to release!

other info that might help us debug this:
1 lock held by syz-executor342/5826:
 #0: ffff8880300b4790 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182

stack backtrace:
CPU: 1 UID: 0 PID: 5826 Comm: syz-executor342 Not tainted 6.15.0-rc6-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_unlock_imbalance_bug kernel/locking/lockdep.c:5296 [inline]
 print_unlock_imbalance_bug+0x11b/0x130 kernel/locking/lockdep.c:5270
 __lock_release kernel/locking/lockdep.c:5535 [inline]
 lock_release+0x242/0x2f0 kernel/locking/lockdep.c:5887
 __mutex_unlock_slowpath+0xa2/0x6a0 kernel/locking/mutex.c:907
 seq_read_iter+0x60d/0x12c0 fs/seq_file.c:251
 seq_read+0x39e/0x4e0 fs/seq_file.c:162
 vfs_read+0x1de/0xc70 fs/read_write.c:568
 ksys_read+0x12a/0x240 fs/read_write.c:713
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f790ac9d2e9
Code: 48 83 c4 28 c3 e8 17 1a 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd4c5723b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007ffd4c5723c0 RCX: 00007f790ac9d2e9
RDX: 0000000000000080 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000001 

Crashes (29):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/12 14:53 upstream 82f2b0b97b36 77908e5f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/01/31 20:46 upstream 69e858e0b8b2 aa47157c .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/05/14 18:38 upstream 9f35e33144ae a4fa04ef .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/05/12 14:04 upstream 82f2b0b97b36 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/05/10 20:17 upstream 1a33418a69cc 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/05/02 13:05 upstream ebd297a2affa d7f099d1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/05/02 07:16 upstream ebd297a2affa 51b137cd .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/05/01 00:00 upstream b6ea1680d0ac 937aafd7 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/04/22 07:42 upstream a33b5a08cbbd 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/04/13 22:21 upstream 5aaaedb0cb54 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/04/13 00:36 upstream 3bde70a2c827 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/03/31 18:35 upstream 4e82c87058f4 d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/03/24 19:27 upstream 38fec10eb60d 875573af .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/03/23 10:52 upstream 183601b78a9b 4e8d3850 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/03/21 01:37 upstream 5fc319360819 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/03/13 02:23 upstream b7f94fcf5546 1a5d9317 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/03/12 00:48 upstream 0b46b049d6ec f2eee6b3 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/03/06 18:29 upstream 848e07631744 831e3629 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/02/24 03:25 upstream d082ecbc71e9 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/02/20 09:07 upstream 87a132e73910 50668798 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/02/18 04:21 upstream 2408a807bfc3 429ea007 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/02/14 01:30 upstream ab68d7eb7b1a d9a046cf .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/02/09 21:24 upstream 69b54314c975 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/02/03 15:00 upstream 2014c95afece a21a8419 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/02/03 14:53 upstream 2014c95afece a21a8419 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/02/02 04:53 upstream 69e858e0b8b2 568559e4 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/01/31 20:21 upstream 69e858e0b8b2 aa47157c .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/01/27 02:03 upstream c2da8b3f914f 9fbd772e .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
2025/01/24 22:25 upstream 68732c0bf97c 1293872d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING: bad unlock balance in seq_read_iter
* Struck through repros no longer work on HEAD.