syzbot


INFO: task hung in blkdev_read_iter

Status: upstream: reported C repro on 2025/05/06 10:05
Subsystems: block
[Documentation on labels]
Reported-by: syzbot+afa7aef0c237038586e7@syzkaller.appspotmail.com
First crash: 336d, last: 6d10h
Cause bisection: failed (error log, bisect log)
  
Fix bisection: failed (error log, bisect log)
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [block?] INFO: task hung in blkdev_read_iter 0 (1) 2025/05/06 10:05
Last patch testing requests (3)
Created Duration User Patch Repo Result
2026/03/15 07:52 1h37m retest repro upstream report log
2026/03/15 07:40 50m retest repro upstream report log
2025/05/16 10:55 43m retest repro upstream report log
Fix bisection attempts (6)
Created Duration User Patch Repo Result
2026/02/13 19:15 3h09m bisect fix upstream error job log
2026/01/14 15:14 3h41m bisect fix upstream OK (0) job log log
2025/11/25 00:39 2h41m bisect fix upstream OK (0) job log log
2025/10/22 05:27 3h00m bisect fix upstream OK (0) job log log
2025/09/08 06:16 4h47m bisect fix upstream OK (0) job log log
2025/07/24 17:23 3h04m bisect fix upstream OK (0) job log log

Sample crash report:
INFO: task syz.2.19:6094 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:27072 pid:6094  tgid:6094  ppid:5959   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5295 [inline]
 __schedule+0x1585/0x5340 kernel/sched/core.c:6907
 __schedule_loop kernel/sched/core.c:6989 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7004
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061
 rwsem_down_read_slowpath+0x61e/0x920 kernel/locking/rwsem.c:1086
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x99/0x2e0 kernel/locking/rwsem.c:1539
 inode_lock_shared include/linux/fs.h:1043 [inline]
 blkdev_read_iter+0x2f8/0x440 block/fops.c:854
 aio_read+0x33a/0x4d0 fs/aio.c:1602
 __io_submit_one fs/aio.c:-1 [inline]
 io_submit_one+0x79d/0x14c0 fs/aio.c:2052
 __do_sys_io_submit fs/aio.c:2111 [inline]
 __se_sys_io_submit+0x195/0x340 fs/aio.c:2081
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1288d9c799
RSP: 002b:00007ffc0e033eb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007f1289015fa0 RCX: 00007f1288d9c799
RDX: 00002000000000c0 RSI: 00000000000000ca RDI: 00007f1289d16000
RBP: 00007f1288e32bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1289015fac R14: 00007f1289015fa0 R15: 00007f1289015fa0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e7602e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5583:
 #0: ffff8880358730a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211
2 locks held by syz.3.20/6093:
1 lock held by syz.2.19/6094:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.4.21/6096:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.1.18/6097:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.0.17/6099:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.5.22/6236:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.9.26/6239:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.8.25/6240:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.6.23/6241:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.7.24/6242:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.3.27/6323:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.0.28/6334:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.1.29/6349:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.2.30/6350:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.4.31/6351:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.5.32/6463:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.9.33/6471:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.8.36/6486:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.7.35/6488:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.6.34/6490:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.3.37/6581:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.0.38/6594:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.1.39/6596:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.4.41/6597:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.2.40/6598:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.5.42/6702:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.9.43/6716:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.8.44/6728:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.6.45/6733:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
1 lock held by syz.7.46/6734:
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline]
 #0: ffff88802398c128 (&sb->s_type->i_mutex_key#11){++++}-{4:4}, at: blkdev_read_iter+0x2f8/0x440 block/fops.c:854
2 locks held by dhcpcd/6736:
 #0: ffff888076bac260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
 #0: ffff888076bac260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x33/0xe10 net/packet/af_packet.c:3197
 #1: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
 #1: ffffffff8e766578 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xfd9/0x1030 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1168 Comm: kworker/1:1H Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: kblockd blk_mq_run_work_fn
RIP: 0010:__lock_acquire+0x9e/0x2cf0 kernel/locking/lockdep.c:-1
Code: 8b 0d 56 a5 85 18 85 c9 0f 95 c0 83 fe 08 0f 92 c2 08 c2 0f 84 49 01 00 00 83 fe 01 77 0c 89 f0 49 8b 44 c1 08 48 85 c0 75 21 <31> ed 4c 89 cf 31 d2 4c 89 cb e8 63 f1 ff ff 48 85 c0 0f 84 76 13
RSP: 0018:ffffc90004ddf940 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000246 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffc90004ddfc40
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffc90004ddfc40
R10: dffffc0000000000 R11: fffffbfff2023137 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125564000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561146263028 CR3: 00000000741e8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
 process_one_work kernel/workqueue.c:3251 [inline]
 process_scheduled_works+0xa42/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/01 06:45 upstream 9197e5949a41 43249bac .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in blkdev_read_iter
2025/05/02 09:52 upstream ebd297a2affa 51b137cd .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in blkdev_read_iter
2026/03/21 13:11 upstream 42bddab0563f 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in blkdev_read_iter
2025/12/15 07:08 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in blkdev_read_iter
2025/10/23 22:40 upstream 43e9ad0c55a3 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in blkdev_read_iter
2025/06/23 14:26 upstream 86731a2a651e d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in blkdev_read_iter
2025/05/27 21:15 upstream 914873bc7df9 874a1386 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in blkdev_read_iter
2025/04/30 22:14 upstream b6ea1680d0ac ce7952f4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in blkdev_read_iter
2026/03/26 12:28 upstream d2a43e7f89da c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in blkdev_read_iter
2025/11/27 02:00 upstream 30f09200cc4a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in blkdev_read_iter
2025/09/20 15:59 upstream cd89d487374c 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in blkdev_read_iter
2026/02/22 15:57 linux-next d4906ae14a5f 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in blkdev_read_iter
* Struck through repros no longer work on HEAD.