syzbot


INFO: task hung in blkdev_fallocate

Status: upstream: reported C repro on 2023/03/08 05:38
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+dad55e856d8e05000edf@syzkaller.appspotmail.com
First crash: 998d, last: 19h52m
Fix bisection: failed (error log, bisect log)
  
Bug presence (1)
Date Name Commit Repro Result
2023/05/09 upstream (ToT) ba0ad6ed89fd 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-5.15 INFO: task hung in blkdev_fallocate origin:upstream 1 C error 33 15d 993d 0/3 upstream: reported C repro on 2023/03/12 23:16
upstream INFO: task hung in blkdev_fallocate block 1 C error error 1692 4d19h 1427d 0/29 upstream: reported C repro on 2022/01/03 09:11

Sample crash report:
INFO: task syz.1.18:4517 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:26688 pid:4517  ppid:4399   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
 filemap_invalidate_lock include/linux/fs.h:803 [inline]
 blkdev_fallocate+0x20e/0x460 block/fops.c:657
 vfs_fallocate+0x584/0x6f0 fs/open.c:323
 ksys_fallocate fs/open.c:346 [inline]
 __do_sys_fallocate fs/open.c:354 [inline]
 __se_sys_fallocate fs/open.c:352 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:352
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f46ad38f749
RSP: 002b:00007ffee8d4db58 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f46ad5e5fa0 RCX: 00007f46ad38f749
RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000004
RBP: 00007f46ad413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 7fffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f46ad5e5fa0 R14: 00007f46ad5e5fa0 R15: 0000000000000004
 </TASK>
INFO: task syz.0.17:4518 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:25888 pid:4518  ppid:4392   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
 filemap_invalidate_lock include/linux/fs.h:803 [inline]
 blkdev_fallocate+0x20e/0x460 block/fops.c:657
 vfs_fallocate+0x584/0x6f0 fs/open.c:323
 ksys_fallocate fs/open.c:346 [inline]
 __do_sys_fallocate fs/open.c:354 [inline]
 __se_sys_fallocate fs/open.c:352 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:352
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f07bc18f749
RSP: 002b:00007fffcab2c718 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f07bc3e5fa0 RCX: 00007f07bc18f749
RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000004
RBP: 00007f07bc213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 7fffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f07bc3e5fa0 R14: 00007f07bc3e5fa0 R15: 0000000000000004
 </TASK>
INFO: task syz.3.20:4534 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:26688 pid:4534  ppid:4401   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
 filemap_invalidate_lock include/linux/fs.h:803 [inline]
 blkdev_fallocate+0x20e/0x460 block/fops.c:657
 vfs_fallocate+0x584/0x6f0 fs/open.c:323
 ksys_fallocate fs/open.c:346 [inline]
 __do_sys_fallocate fs/open.c:354 [inline]
 __se_sys_fallocate fs/open.c:352 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:352
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f737818f749
RSP: 002b:00007ffeed3739d8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f73783e5fa0 RCX: 00007f737818f749
RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000004
RBP: 00007f7378213f91 R08: 0000000000000000 R09: 0000000000000000
R10: 7fffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f73783e5fa0 R14: 00007f73783e5fa0 R15: 0000000000000004
 </TASK>
INFO: task syz.4.21:4535 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:26688 pid:4535  ppid:4405   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 rwsem_down_write_slowpath+0xbed/0x1090 kernel/locking/rwsem.c:1189
 filemap_invalidate_lock include/linux/fs.h:803 [inline]
 blkdev_fallocate+0x20e/0x460 block/fops.c:657
 vfs_fallocate+0x584/0x6f0 fs/open.c:323
 ksys_fallocate fs/open.c:346 [inline]
 __do_sys_fallocate fs/open.c:354 [inline]
 __se_sys_fallocate fs/open.c:352 [inline]
 __x64_sys_fallocate+0xbd/0x100 fs/open.c:352
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2c7b98f749
RSP: 002b:00007ffd34f3abf8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f2c7bbe5fa0 RCX: 00007f2c7b98f749
RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000004
RBP: 00007f2c7ba13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 7fffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2c7bbe5fa0 R14: 00007f2c7bbe5fa0 R15: 0000000000000004
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u4:0/9:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2b630 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2be50 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
 #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2aca0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by kworker/u4:2/40:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90000b17d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by getty/4027:
 #0: ffff88802f8ce098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
3 locks held by kworker/1:4/4321:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90002e87d00 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffff88804bf32240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x26b/0x32b0 drivers/net/netdevsim/fib.c:1491
1 lock held by syz.2.19/4513:
1 lock held by syz.1.18/4517:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.0.17/4518:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.3.20/4534:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.4.21/4535:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.5.22/4644:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.6.23/4650:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.7.24/4659:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.8.25/4663:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.9.26/4664:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.1.27/4727:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.2.28/4751:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.0.29/4759:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.3.30/4763:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.4.31/4767:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.5.32/4808:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.6.33/4865:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.7.34/4900:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.8.35/4901:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.9.36/4905:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.1.37/4921:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.2.38/4941:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.0.39/4998:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.3.40/5012:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.4.41/5018:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.5.42/5047:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.6.43/5055:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.7.44/5097:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.8.45/5137:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.9.46/5149:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz-executor/5170:
 #0: ffffffff8cb30978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #0: ffffffff8cb30978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962
1 lock held by syz.1.47/5172:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
1 lock held by syz.2.48/5183:
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #0: ffff8880178908c0 (mapping.invalidate_lock#2){++++}-{3:3}, at: blkdev_fallocate+0x20e/0x460 block/fops.c:657
2 locks held by syz-executor/5195:
 #0: ffffffff8dd416e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8dd416e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6147
 #1: ffffffff8cb30978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #1: ffffffff8cb30978 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x346/0x830 kernel/rcu/tree_exp.h:962

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

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 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4361 Comm: kworker/0:6 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events kfree_rcu_work
RIP: 0010:unwind_next_frame+0x1774/0x20b0 arch/x86/kernel/unwind_orc.c:621
Code: 48 01 c6 48 89 df 4c 89 fa e8 58 09 00 00 84 c0 0f 84 41 01 00 00 49 bd 00 00 00 00 00 fc ff df 48 8b 44 24 18 42 0f b6 04 28 <84> c0 0f 85 29 06 00 00 8b 84 24 8c 00 00 00 39 03 48 8b 7c 24 58
RSP: 0018:ffffc90003f575d0 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffc90003f57708 RCX: 0000000000000001
RDX: ffffc90003f57748 RSI: dffffc0000000000 RDI: ffffc90003f57790
RBP: ffffffff8e9d385e R08: ffffc90003f57790 R09: ffffc90003f57758
R10: fffff520007eaeed R11: 1ffff920007eaeeb R12: ffffffff8e9d385d
R13: dffffc0000000000 R14: ffffc90003f57758 R15: ffffffff8e9d385c
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555572c22808 CR3: 000000007fb01000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __unwind_start+0x5bb/0x740 arch/x86/kernel/unwind_orc.c:717
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xda/0x140 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free_bulk+0x348/0x460 mm/slub.c:3805
 kfree_bulk include/linux/slab.h:475 [inline]
 kfree_rcu_work+0x33f/0x890 kernel/rcu/tree.c:3091
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (26):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/29 13:32 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2025/07/28 10:23 linux-6.1.y 3594f306da12 fb8f743d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2023/04/01 06:15 linux-6.1.y 3b29299e5f60 f325deb0 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/03/20 13:59 linux-6.1.y d7543167affd a485f239 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/05/02 03:13 linux-6.1.y ca48fc16c493 62df2017 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/13 04:06 linux-6.1.y 1cc3fcf63192 5205ef30 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2024/09/25 06:36 linux-6.1.y e526b12bf916 5643e0e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/09/25 06:25 linux-6.1.y e526b12bf916 5643e0e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/09/25 06:13 linux-6.1.y e526b12bf916 5643e0e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/09/25 05:43 linux-6.1.y e526b12bf916 5643e0e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/06/23 17:17 linux-6.1.y eb44d83053d6 edc5149a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/04/07 22:08 linux-6.1.y 347385861c50 ca620dd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/04/02 04:52 linux-6.1.y e5cd595e23c1 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/04/01 12:41 linux-6.1.y e5cd595e23c1 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/01/22 13:28 linux-6.1.y 8fd7f4462453 9bd8dcda .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in blkdev_fallocate
2024/07/09 03:31 linux-6.1.y 7753af06eebf bc23a442 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2024/07/08 15:47 linux-6.1.y 7753af06eebf cde64f7d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2024/05/20 01:36 linux-6.1.y 4078fa637fcd c0f1611a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/10/28 20:20 linux-6.1.y 32c9cdbe383c 3c418d72 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/17 18:30 linux-6.1.y 7eaef76fbc46 7939252e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/17 10:45 linux-6.1.y 7eaef76fbc46 18b58603 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/16 18:12 linux-6.1.y 6449a0ba6843 18b58603 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/14 11:30 linux-6.1.y 6449a0ba6843 0d5c4377 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/13 12:28 linux-6.1.y 6449a0ba6843 026e2200 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/12 20:22 linux-6.1.y 1cc3fcf63192 5205ef30 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
2023/03/08 05:38 linux-6.1.y 42616e0f09fb d2b00170 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in blkdev_fallocate
* Struck through repros no longer work on HEAD.