WARNING in blk_mq_free_tag_set

Status: upstream: reported syz repro on 2026/08/08 20:09
Subsystems: block
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+02b37e31e64ea5cb6d29@syzkaller.appspotmail.com
First crash: 7d17h, last: 39m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
3f7a095a assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in blk_mq_free_tag_set 2026/08/08 21:19 2026/08/08 21:19 2026/08/08 21:54 5d63f80b
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [block?] WARNING in blk_mq_free_tag_set 0 (1) 2026/08/08 20:09

Sample crash report:
------------[ cut here ]------------
timer_delete_sync(&sdp->delay_work) && rcu_segcblist_n_cbs(&sdp->srcu_cblist)
WARNING: kernel/rcu/srcutree.c:707 at cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706, CPU#0: syz.0.31/5977
Modules linked in:
CPU: 0 UID: 0 PID: 5977 Comm: syz.0.31 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706
Code: 72 8a 00 48 83 7d 00 00 4c 8b 74 24 10 0f 85 dd 03 00 00 41 ff c5 41 83 e5 0f 41 83 fd 07 0f 86 e2 fe ff ff e9 ab 00 00 00 90 <0f> 0b 90 4c 8d b5 00 02 00 00 4c 89 f3 48 c1 eb 03 48 b8 00 00 00
RSP: 0018:ffffc90003817cf0 EFLAGS: 00010206
RAX: 1ffffd1ffff81515 RBX: 0000607edaf077c0 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: ffffffff8e45f620 RDI: 00000000ffffffff
RBP: ffffe8ffffc0a7c0 R08: ffffffff90791c7f R09: 1ffffffff20f238f
R10: dffffc0000000000 R11: fffffbfff20f2390 R12: ffff8880268d5000
R13: 0000000000000000 R14: ffffe8ffffc0a8a8 R15: 1ffffffff1ce61de
FS:  00005555604c4500(0000) GS:ffff888124d03000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000036a8bbe61000 CR3: 0000000059b7e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 blk_mq_free_tag_set+0x617/0x780 block/blk-mq.c:4976
 loop_remove+0x4e/0xc0 drivers/block/loop.c:2143
 loop_control_remove drivers/block/loop.c:2201 [inline]
 loop_control_ioctl+0x4a6/0x5a0 drivers/block/loop.c:2243
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f879959e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc1bff6a48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8799825fa0 RCX: 00007f879959e0d9
RDX: 000000000000000a RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 00007f8799635024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8799825fac R14: 00007f8799825fa0 R15: 00007f8799825fa0
 </TASK>

Crashes (229):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/14 13:30 linux-next 2697ef8943c9 b13552fe .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 12:38 linux-next 28d012efb432 67796a05 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 01:48 linux-next 6b8c8af514d7 5d63f80b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/08 19:54 linux-next 6b8c8af514d7 5d63f80b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/08 15:08 linux-next 6b8c8af514d7 5d63f80b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/08 00:06 linux-next ea2bff00da89 e4ef95d6 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/07 21:16 linux-next ea2bff00da89 e4ef95d6 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/07 08:31 linux-next 1701fda2f58e c38879ea .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/07 07:00 linux-next 1701fda2f58e c38879ea .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/14 05:44 linux-next 2697ef8943c9 b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/14 05:05 linux-next 2697ef8943c9 b13552fe .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/14 02:06 linux-next 2697ef8943c9 a9ede23c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 22:31 linux-next 2697ef8943c9 a9ede23c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 21:00 linux-next 2697ef8943c9 a9ede23c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 11:15 linux-next 28d012efb432 67796a05 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 08:57 linux-next 28d012efb432 67796a05 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 06:15 linux-next 28d012efb432 67796a05 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 05:08 linux-next 28d012efb432 67796a05 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 05:04 linux-next 28d012efb432 67796a05 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 04:04 linux-next 28d012efb432 67796a05 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/13 01:38 linux-next 28d012efb432 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 21:07 linux-next 5e6de6a2b522 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 20:15 linux-next 5e6de6a2b522 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 18:37 linux-next 5e6de6a2b522 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 17:07 linux-next 5e6de6a2b522 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 13:38 linux-next 5e6de6a2b522 7ae4acc7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 10:47 linux-next 5e6de6a2b522 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 07:42 linux-next 5e6de6a2b522 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 04:23 linux-next 5e6de6a2b522 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/12 01:12 linux-next 5e6de6a2b522 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 23:40 linux-next 5e6de6a2b522 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 21:28 linux-next 5e6de6a2b522 37a258dd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 20:31 linux-next 3d08ff75a47a 37a258dd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 15:45 linux-next 3d08ff75a47a 37a258dd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 13:01 linux-next 3d08ff75a47a 37a258dd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 11:50 linux-next 3d08ff75a47a 37a258dd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 10:49 linux-next 3d08ff75a47a 37a258dd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 05:04 linux-next 3d08ff75a47a 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 02:26 linux-next 3d08ff75a47a 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/11 00:53 linux-next 3d08ff75a47a 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 23:18 linux-next 3d08ff75a47a 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 19:23 linux-next 6b8c8af514d7 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 17:49 linux-next 6b8c8af514d7 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 14:53 linux-next 6b8c8af514d7 039457bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 12:20 linux-next 6b8c8af514d7 558388e4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 11:03 linux-next 6b8c8af514d7 558388e4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 07:07 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 05:55 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 04:55 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/10 03:09 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
2026/08/09 23:45 linux-next 6b8c8af514d7 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in blk_mq_free_tag_set
* Struck through repros no longer work on HEAD.