syzbot


INFO: task hung in blkdev_fallocate

Status: upstream: reported C repro on 2023/03/12 23:16
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+d1600ddb4950c2beebf5@syzkaller.appspotmail.com
First crash: 1096d, last: 5d17h
Fix bisection: failed (error log, bisect log)
  
Bug presence (1)
Date Name Commit Repro Result
2023/05/06 upstream (ToT) 2e1e1337881b C [report] INFO: task hung in blkdev_fallocate
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in blkdev_fallocate origin:upstream 1 C error 27 93d 1101d 0/3 upstream: reported C repro on 2023/03/08 05:38
upstream INFO: task hung in blkdev_fallocate block 1 C error error 1702 11d 1530d 0/29 upstream: reported C repro on 2022/01/03 09:11
Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/03/02 03:34 12m retest repro linux-5.15.y report log
2026/03/02 03:34 13m retest repro linux-5.15.y report log
2026/03/02 03:34 13m retest repro linux-5.15.y report log
2026/03/02 03:34 17m retest repro linux-5.15.y report log
2026/03/02 03:34 11m retest repro linux-5.15.y report log
2026/02/16 02:26 14m retest repro linux-5.15.y report log
2026/01/23 15:26 13m retest repro linux-5.15.y report log
2026/01/23 15:26 17m retest repro linux-5.15.y report log
2026/01/23 15:26 11m retest repro linux-5.15.y report log
2026/01/09 01:36 15m retest repro linux-5.15.y report log
Fix bisection attempts (3)
Created Duration User Patch Repo Result
2023/10/11 04:56 0m bisect fix linux-5.15.y error job log
2023/06/28 01:43 1h06m bisect fix linux-5.15.y OK (0) job log log
2023/04/26 04:45 47m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
INFO: task syz.1.18:4401 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.18        state:D stack:27152 pid: 4401 ppid:  4327 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 rwsem_down_write_slowpath+0xc87/0x1260 kernel/locking/rwsem.c:1165
 filemap_invalidate_lock include/linux/fs.h:832 [inline]
 blkdev_fallocate+0x263/0x4d0 block/fops.c:603
 vfs_fallocate+0x587/0x6f0 fs/open.c:308
 ksys_fallocate fs/open.c:331 [inline]
 __do_sys_fallocate fs/open.c:339 [inline]
 __se_sys_fallocate fs/open.c:337 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6bc6bd7799
RSP: 002b:00007ffddbd8a1d8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f6bc6e50fa0 RCX: 00007f6bc6bd7799
RDX: 0000000000000c00 RSI: 0000000000000011 RDI: 0000000000000004
RBP: 00007f6bc6c6dbd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000080001002000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6bc6e50fac R14: 00007f6bc6e50fa0 R15: 00007f6bc6e50fa0
 </TASK>
INFO: task syz.0.17:4403 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:27600 pid: 4403 ppid:  4323 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 rwsem_down_write_slowpath+0xc87/0x1260 kernel/locking/rwsem.c:1165
 filemap_invalidate_lock include/linux/fs.h:832 [inline]
 blkdev_fallocate+0x263/0x4d0 block/fops.c:603
 vfs_fallocate+0x587/0x6f0 fs/open.c:308
 ksys_fallocate fs/open.c:331 [inline]
 __do_sys_fallocate fs/open.c:339 [inline]
 __se_sys_fallocate fs/open.c:337 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe096f72799
RSP: 002b:00007fffeb051398 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fe0971ebfa0 RCX: 00007fe096f72799
RDX: 0000000000000c00 RSI: 0000000000000011 RDI: 0000000000000004
RBP: 00007fe097008bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000080001002000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe0971ebfac R14: 00007fe0971ebfa0 R15: 00007fe0971ebfa0
 </TASK>
INFO: task syz.3.20:4404 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.20        state:D stack:27600 pid: 4404 ppid:  4336 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 rwsem_down_write_slowpath+0xc87/0x1260 kernel/locking/rwsem.c:1165
 filemap_invalidate_lock include/linux/fs.h:832 [inline]
 blkdev_fallocate+0x263/0x4d0 block/fops.c:603
 vfs_fallocate+0x587/0x6f0 fs/open.c:308
 ksys_fallocate fs/open.c:331 [inline]
 __do_sys_fallocate fs/open.c:339 [inline]
 __se_sys_fallocate fs/open.c:337 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa938c70799
RSP: 002b:00007fffb1a79b08 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fa938ee9fa0 RCX: 00007fa938c70799
RDX: 0000000000000c00 RSI: 0000000000000011 RDI: 0000000000000004
RBP: 00007fa938d06bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000080001002000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa938ee9fac R14: 00007fa938ee9fa0 R15: 00007fa938ee9fa0
 </TASK>
INFO: task syz.4.21:4405 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21        state:D stack:27600 pid: 4405 ppid:  4334 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 rwsem_down_write_slowpath+0xc87/0x1260 kernel/locking/rwsem.c:1165
 filemap_invalidate_lock include/linux/fs.h:832 [inline]
 blkdev_fallocate+0x263/0x4d0 block/fops.c:603
 vfs_fallocate+0x587/0x6f0 fs/open.c:308
 ksys_fallocate fs/open.c:331 [inline]
 __do_sys_fallocate fs/open.c:339 [inline]
 __se_sys_fallocate fs/open.c:337 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f0066aae799
RSP: 002b:00007ffd45af90e8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f0066d27fa0 RCX: 00007f0066aae799
RDX: 0000000000000c00 RSI: 0000000000000011 RDI: 0000000000000004
RBP: 00007f0066b44bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000080001002000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0066d27fac R14: 00007f0066d27fa0 R15: 00007f0066d27fa0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3949:
 #0: ffff88802c517098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026562e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
1 lock held by syz.2.19/4392:
1 lock held by syz.1.18/4401:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.0.17/4403:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.3.20/4404:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.4.21/4405:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.5.22/4465:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.7.24/4507:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.8.25/4508:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.6.23/4510:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.9.26/4511:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.2.27/4526:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.0.28/4567:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.4.31/4596:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.3.30/4597:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.1.29/4598:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.5.32/4610:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.7.33/4631:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.6.34/4712:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.9.36/4721:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.8.35/4722:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.2.37/4723:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.0.38/4729:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.1.39/4775:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.4.41/4805:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.3.40/4806:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.5.42/4818:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.7.43/4824:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
1 lock held by syz.6.44/4846:
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:832 [inline]
 #0: ffff888140867338 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x263/0x4d0 block/fops.c:603
4 locks held by syz-executor/4849:
 #0: ffff88807f2ac460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x295/0xd60 fs/read_write.c:590
 #1: ffff888046a59488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287
 #2: ffff888023f2a660 (kn->active#362){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288
 #3: ffffffff8cd79f88 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd3/0x3a0 drivers/net/netdevsim/bus.c:344
8 locks held by syz-executor/4850:
 #0: ffff88807f2ac460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x295/0xd60 fs/read_write.c:590
 #1: ffff88804af9f488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e5/0x4c0 fs/kernfs/file.c:287
 #2: ffff888023f2a660 (kn->active#362){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x208/0x4c0 fs/kernfs/file.c:288
 #3: ffffffff8cd79f88 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd3/0x3a0 drivers/net/netdevsim/bus.c:344
 #4: ffff888077ad6178 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:764 [inline]
 #4: ffff888077ad6178 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1044 [inline]
 #4: ffff888077ad6178 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb0/0x750 drivers/base/dd.c:1259
 #5: ffff888077ad7400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1359 [inline]
 #5: ffff888077ad7400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_reload_destroy+0x115/0x240 drivers/net/netdevsim/dev.c:1561
 #6: ffffffff8d43cb48 (rtnl_mutex){+.+.}-{3:3}, at: nsim_destroy+0x3b/0x150 drivers/net/netdevsim/netdev.c:381
 #7: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #7: ffffffff8c323528 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2d1/0x750 kernel/rcu/tree_exp.h:845
1 lock held by syz-executor/4864:
 #0: ffffffff8d43cb48 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d43cb48 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7ee/0xf30 net/core/rtnetlink.c:5681

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 14 Comm: ksoftirqd/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:check_preemption_disabled+0x42/0x110 lib/smp_processor_id.c:55
Code: 65 8b 05 59 9c 45 76 65 8b 0d c2 f6 45 76 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04
RSP: 0018:ffffc90000d37a48 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: b2ee7db4bad51c00
RDX: 0000000000000000 RSI: ffffffff8a79f960 RDI: ffffffff8a79f920
RBP: ffffc90000d37bc0 R08: ffffffff8d89e36f R09: 1ffffffff1b13c6d
R10: dffffc0000000000 R11: fffffbfff1b13c6e R12: ffffffff8c31eaa0
R13: 1ffff920001a6f60 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a8468db010 CR3: 0000000020bc5000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline]
 rcu_is_watching+0x11/0xa0 kernel/rcu/tree.c:1123
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0xc8/0x400 kernel/locking/lockdep.c:5594
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 blk_stat_add+0x71/0x460 block/blk-stat.c:63
 __blk_mq_end_request+0x1db/0x380 block/blk-mq.c:558
 blk_complete_reqs block/blk-mq.c:588 [inline]
 blk_done_softirq+0xfa/0x140 block/blk-mq.c:593
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 run_ksoftirqd+0xa4/0x100 kernel/softirq.c:943
 smpboot_thread_fn+0x4f6/0x970 kernel/smpboot.c:164
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (35):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/07 23:39 linux-5.15.y 91d48252ad4b 5cb44a80 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2026/02/01 17:33 linux-5.15.y 9eec9a14ee10 6b8752f2 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2025/09/14 17:45 linux-5.15.y 43bb85222e53 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2025/09/09 16:09 linux-5.15.y 7a6c2d093c45 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2025/07/06 09:25 linux-5.15.y 3dea0e7f549e 4f67c4ae .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 09:48 linux-5.15.y 3a5928702e71 89298aad .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/04/06 17:44 linux-5.15.y 9465fef4ae35 ca620dd8 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2023/05/27 23:44 linux-5.15.y 1fe619a7d252 cf184559 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2023/03/27 02:40 linux-5.15.y 115472395b0a fbf0499a .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/05/17 06:01 linux-5.15.y 284087d4f7d5 c2e07261 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2024/04/26 04:46 linux-5.15.y c52b9710c83d 8bdc0f22 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2024/04/07 01:37 linux-5.15.y 9465fef4ae35 ca620dd8 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/05/07 22:47 linux-5.15.y 8a7f2a5c5aa1 90c93c40 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/13 02:39 linux-5.15.y bbf9f29bac04 5205ef30 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2024/09/24 08:36 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:35 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:33 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:29 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:28 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:26 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:22 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:20 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:19 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:15 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:14 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:07 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:05 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/09/24 08:04 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/01/25 12:21 linux-5.15.y ddcaf4999061 1e153dc8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2024/03/15 18:09 linux-5.15.y 574362648507 d615901c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2024/03/08 19:59 linux-5.15.y 574362648507 8e75c913 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/08/22 01:20 linux-5.15.y f6f7927ac664 6b415825 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in blkdev_fallocate
2023/03/14 10:29 linux-5.15.y 2ddbd0f967b3 0d5c4377 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/13 10:43 linux-5.15.y 2ddbd0f967b3 5205ef30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/12 23:15 linux-5.15.y bbf9f29bac04 5205ef30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in blkdev_fallocate
* Struck through repros no longer work on HEAD.