syzbot


WARNING: refcount bug in blk_mq_dispatch_rq_list (2)

Status: upstream: reported C repro on 2024/09/19 10:57
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+4e6abb14fef0fca71895@syzkaller.appspotmail.com
First crash: 65d, last: 40d
Bug presence (2)
Date Name Commit Repro Result
2024/09/20 linux-5.15.y (ToT) 3a5928702e71 C [report] WARNING: refcount bug in blk_mq_dispatch_rq_list
2024/09/20 upstream (ToT) baeb9a7d8b60 C Didn't crash
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING: refcount bug in blk_mq_dispatch_rq_list 2 565d 591d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:06
Last patch testing requests (1)
Created Duration User Patch Repo Result
2024/10/15 00:08 0m retest repro linux-5.15.y error
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2024/10/11 02:47 2h22m fix candidate upstream OK (0) job log

Sample crash report:
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 263 at lib/refcount.c:28 refcount_warn_saturate+0x14e/0x1a0 lib/refcount.c:28
Modules linked in:

CPU: 1 PID: 263 Comm: kworker/1:1H Not tainted 5.15.167-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: kblockd blk_mq_run_work_fn

RIP: 0010:refcount_warn_saturate+0x14e/0x1a0 lib/refcount.c:28
Code: 09 01 48 c7 c7 a0 c7 d8 8a e8 ee 9e 42 fd 0f 0b eb 8d e8 05 f5 76 fd c6 05 8e 63 cc 09 01 48 c7 c7 00 c8 d8 8a e8 d2 9e 42 fd <0f> 0b e9 6e ff ff ff e8 e6 f4 76 fd c6 05 70 63 cc 09 01 48 c7 c7
RSP: 0018:ffffc900020077a8 EFLAGS: 00010246
RAX: e7d7f313f2a78400 RBX: 0000000000000003 RCX: ffff88801e1c0000
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff81668a3c R09: fffffbfff20e2424
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88802123d000
R13: dffffc0000000000 R14: ffffc90002007a40 R15: ffff8880212ee600
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efcac919d58 CR3: 000000001ea3a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 blk_mq_end_request block/blk-mq.c:577 [inline]
 blk_mq_dispatch_rq_list+0xc47/0x1f30 block/blk-mq.c:1408
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:200 [inline]
 blk_mq_do_dispatch_sched+0x755/0xd50 block/blk-mq-sched.c:214
 __blk_mq_sched_dispatch_requests+0x39b/0x490
 blk_mq_sched_dispatch_requests+0xec/0x160 block/blk-mq-sched.c:366
 __blk_mq_run_hw_queue+0x11a/0x1b0 block/blk-mq.c:1511
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/19 12:21 linux-5.15.y 3a5928702e71 c673ca06 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: refcount bug in blk_mq_dispatch_rq_list
2024/09/19 11:36 linux-5.15.y 3a5928702e71 c673ca06 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: refcount bug in blk_mq_dispatch_rq_list
2024/10/15 06:22 linux-5.15.y 3a5928702e71 b01b6661 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: refcount bug in blk_mq_dispatch_rq_list
2024/09/27 06:41 linux-5.15.y 3a5928702e71 9314348a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: refcount bug in blk_mq_dispatch_rq_list
2024/09/19 10:57 linux-5.15.y 3a5928702e71 c673ca06 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: refcount bug in blk_mq_dispatch_rq_list
* Struck through repros no longer work on HEAD.