possible deadlock in blk_request_module (2)

Status: upstream: reported C repro on 2026/05/25 20:24
Subsystems: raid
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+fb0ff9bfe34ad282ebd4@syzkaller.appspotmail.com
First crash: 172d, last: 2h10m
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
cb0dd327 repro-c Reproduced: ✅ ❓ possible deadlock in blk_request_module (2) 2026/10/15 18:03 2026/10/15 18:03 2026/10/15 19:02 3f2522c6
5aabafd3 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ possible deadlock in blk_request_module (2) 2026/06/02 05:12 2026/06/02 05:12 2026/06/02 05:18 1095583b
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[syzbot] [block?] possible deadlock in blk_request_module (2) 0 (2) 2026/10/15 20:08
Re: [PATCH v3] loop: Fix NULL pointer dereference in lo_rw_aio() 8 (8) 2026/05/30 23:57
[PATCH] block: assign caller-specific lockdep class to disk->open_mutex 2 (2) 2026/05/30 22:50
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 possible deadlock in blk_request_module (2) 4 6 328d 489d 0/3 auto-obsoleted due to no activity on 2026/03/27 18:48
linux-6.1 possible deadlock in blk_request_module 4 19 2h09m 20d 0/3 upstream: reported on 2026/10/20 20:24
linux-5.15 possible deadlock in blk_request_module (4) 4 24 3d04h 60d 0/3 upstream: reported on 2026/09/10 23:54
linux-5.15 possible deadlock in blk_request_module (3) 4 2 198d 220d 0/3 auto-obsoleted due to no activity on 2026/08/04 13:53
linux-6.6 possible deadlock in blk_request_module 4 13 1h55m 66d 0/2 upstream: reported on 2026/09/05 07:50
linux-5.15 possible deadlock in blk_request_module 4 6 724d 854d 0/3 auto-obsoleted due to no activity on 2025/02/24 02:18
upstream possible deadlock in blk_request_module block 4 2 1829d 1874d 0/29 auto-closed as invalid on 2022/03/06 21:21
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/10/15 19:31 35m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git b810335a0699d1810683796b0e3ffe8827ddfe6c report job log log

Sample crash report:
md: async del_gendisk mode will be removed in future, please upgrade to mdadm-4.5+
block device autoloading is deprecated and will be removed.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz-executor230/5656 is trying to acquire lock:
ffffffff9096c3e0 (major_names_lock){+.+.}-{4:4}, at: blk_probe_dev block/genhd.c:885 [inline]
ffffffff9096c3e0 (major_names_lock){+.+.}-{4:4}, at: blk_request_module+0x35/0x2a0 block/genhd.c:901

but task is already holding lock:
ffff88807f292358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_lock drivers/md/md.h:713 [inline]
ffff88807f292358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_suspend_and_lock+0x48/0xf0 drivers/md/md.h:1026

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&mddev->reconfig_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821
       mddev_lock_nointr drivers/md/md.h:734 [inline]
       md_alloc+0x81e/0xf40 drivers/md/md.c:6413
       md_alloc_and_put+0x1a/0x1f0 drivers/md/md.c:6452
       blk_probe_dev block/genhd.c:888 [inline]
       blk_request_module+0x27d/0x2a0 block/genhd.c:-1
       blkdev_get_no_open+0x3f/0xe0 block/bdev.c:870
       blkdev_open+0x1d7/0x600 block/fops.c:678
       do_dentry_open+0x80e/0x1360 fs/open.c:1000
       vfs_open_consume+0x4a/0x350 fs/open.c:1131
       do_open fs/namei.c:4845 [inline]
       path_openat+0x16fc/0x20f0 fs/namei.c:5010
       do_file_open+0x23e/0x4a0 fs/namei.c:5039
       do_sys_openat2+0x115/0x200 fs/open.c:1442
       do_sys_open fs/open.c:1448 [inline]
       __do_sys_openat fs/open.c:1788 [inline]
       __se_sys_openat fs/open.c:1783 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1783
       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

-> #1 (disks_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821
       md_alloc+0x40/0xf40 drivers/md/md.c:6355
       md_alloc_and_put+0x1a/0x1f0 drivers/md/md.c:6452
       blk_probe_dev block/genhd.c:888 [inline]
       blk_request_module+0x27d/0x2a0 block/genhd.c:-1
       blkdev_get_no_open+0x3f/0xe0 block/bdev.c:870
       blkdev_open+0x1d7/0x600 block/fops.c:678
       do_dentry_open+0x80e/0x1360 fs/open.c:1000
       vfs_open_consume+0x4a/0x350 fs/open.c:1131
       do_open fs/namei.c:4845 [inline]
       path_openat+0x16fc/0x20f0 fs/namei.c:5010
       do_file_open+0x23e/0x4a0 fs/namei.c:5039
       do_sys_openat2+0x115/0x200 fs/open.c:1442
       do_sys_open fs/open.c:1448 [inline]
       __do_sys_openat fs/open.c:1788 [inline]
       __se_sys_openat fs/open.c:1783 [inline]
       __x64_sys_openat+0x138/0x170 fs/open.c:1783
       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

-> #0 (major_names_lock){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3209 [inline]
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
       lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821
       blk_probe_dev block/genhd.c:885 [inline]
       blk_request_module+0x35/0x2a0 block/genhd.c:901
       blkdev_get_no_open+0x3f/0xe0 block/bdev.c:870
       bdev_file_open_by_dev+0xa0/0x240 block/bdev.c:1091
       md_import_device+0x2e9/0x650 drivers/md/md.c:3861
       md_add_new_disk+0x3a3/0x1850 drivers/md/md.c:7536
       md_ioctl+0x2027/0x2630 drivers/md/md.c:8525
       blkdev_ioctl+0x5e3/0x740 block/ioctl.c:798
       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

other info that might help us debug this:

Chain exists of:
  major_names_lock --> disks_mutex --> &mddev->reconfig_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&mddev->reconfig_mutex);
                               lock(disks_mutex);
                               lock(&mddev->reconfig_mutex);
  lock(major_names_lock);

 *** DEADLOCK ***

locks held by syz-executor230/5656: 1, last CPU#1:
 #0: ffff88807f292358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_lock drivers/md/md.h:713 [inline]
 #0: ffff88807f292358 (&mddev->reconfig_mutex){+.+.}-{4:4}, at: mddev_suspend_and_lock+0x48/0xf0 drivers/md/md.h:1026

stack backtrace:
CPU: 1 UID: 0 PID: 5656 Comm: syz-executor230 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087
 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219
 check_prev_add kernel/locking/lockdep.c:3209 [inline]
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 __mutex_lock_common kernel/locking/mutex.c:646 [inline]
 __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821
 blk_probe_dev block/genhd.c:885 [inline]
 blk_request_module+0x35/0x2a0 block/genhd.c:901
 blkdev_get_no_open+0x3f/0xe0 block/bdev.c:870
 bdev_file_open_by_dev+0xa0/0x240 block/bdev.c:1091
 md_import_device+0x2e9/0x650 drivers/md/md.c:3861
 md_add_new_disk+0x3a3/0x1850 drivers/md/md.c:7536
 md_ioctl+0x2027/0x2630 drivers/md/md.c:8525
 blkdev_ioctl+0x5e3/0x740 block/ioctl.c:798
 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: 0033:0x7f1b86c7fe89
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff44793298 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fff447932a0 RCX: 00007f1b86c7fe89
RDX: 0000200000000240 RSI: 0000000040140921 RDI: 0000000000000003
RBP: 00007fff447932a8 R08: 00007fff447932a8 R09: 00007f1b86c6eb50
R10: 00007fff447932a0 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000002 R14: 00007f1b86d0fca0 R15: 0000000000000002
 </TASK>
md: could not open device unknown-block(0,0).
md: md_import_device returned -6

Crashes (1848):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/29 09:18 linux-next 6d0933ae9d46 b1d00f76 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/10/15 20:07 git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git b810335a0699 7321cd29 .config console log report C ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/10/31 22:34 linux-next 7649ba73f9e7 2041d3f8 .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/10/28 08:36 linux-next 151a134a4e6e 96923c60 .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/10 15:50 upstream b3dfbde62cf1 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/10 14:52 upstream b3dfbde62cf1 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/10 13:44 upstream b3dfbde62cf1 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/10 06:46 upstream b3dfbde62cf1 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 17:52 upstream 7475ea8b5861 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 17:48 upstream 7475ea8b5861 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 10:30 upstream 8a65162514fb 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 10:14 upstream 8a65162514fb 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 08:11 upstream 8a65162514fb 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 04:54 upstream 8a65162514fb 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/08 23:17 upstream fa4ad798f6f6 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/08 19:02 upstream fa4ad798f6f6 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/08 15:12 upstream fa4ad798f6f6 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/08 15:11 upstream fa4ad798f6f6 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/08 07:35 upstream d164c7d754f0 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs possible deadlock in blk_request_module
2026/11/07 20:40 upstream d48723711bae 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root possible deadlock in blk_request_module
2026/10/13 15:08 upstream 24a19b953e2a 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in blk_request_module
2026/11/10 11:14 upstream b3dfbde62cf1 01625235 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/10 10:18 upstream b3dfbde62cf1 01625235 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/10 09:08 upstream b3dfbde62cf1 01625235 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/10 07:51 upstream b3dfbde62cf1 01625235 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/10 02:32 upstream 7475ea8b5861 04b726fe .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/09 16:39 upstream 7475ea8b5861 5cecaf1f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/09 15:21 upstream 7475ea8b5861 5cecaf1f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/09 05:28 upstream 8a65162514fb 5cecaf1f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/09 01:52 upstream 8a65162514fb 5cecaf1f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/08 20:06 upstream fa4ad798f6f6 5cecaf1f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root possible deadlock in blk_request_module
2026/11/10 17:44 linux-next 630059a5a632 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/10 12:25 linux-next 630059a5a632 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/10 05:48 linux-next 630059a5a632 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/10 03:33 linux-next 630059a5a632 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/10 01:32 linux-next 630059a5a632 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in blk_request_module
2026/11/10 00:27 linux-next 630059a5a632 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/09 23:48 linux-next 630059a5a632 70ec0380 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 21:45 linux-next 630059a5a632 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/09 20:43 linux-next 630059a5a632 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/09 19:58 linux-next 630059a5a632 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 18:56 linux-next 630059a5a632 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/09 18:56 linux-next 630059a5a632 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/09 13:36 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in blk_request_module
2026/11/09 11:43 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/09 07:09 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/09 03:04 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/09 00:44 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/08 23:14 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/08 21:27 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/08 17:04 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/08 13:52 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/11/08 12:45 linux-next ddfe51b0a0f5 5cecaf1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root possible deadlock in blk_request_module
2026/05/26 05:42 linux-next c1ecb239fa34 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/05/25 09:22 linux-next c1ecb239fa34 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
2026/05/21 20:20 linux-next 550604d6c9b9 e195359d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce possible deadlock in blk_request_module
* Struck through repros no longer work on HEAD.