syzbot


INFO: task hung in exit_signals (2)

Status: upstream: reported C repro on 2025/09/24 15:37
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+1db5bbe7483cf22dfaff@syzkaller.appspotmail.com
First crash: 68d, last: 21d
Bug presence (1)
Date Name Commit Repro Result
2025/11/10 upstream (ToT) 4ea7c1717f3f C [report] INFO: task hung in exit_mmap
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in exit_signals 1 2 403d 413d 0/3 auto-obsoleted due to no activity on 2025/02/01 10:34
upstream INFO: task hung in exit_signals cgroups 1 3 450d 465d 0/29 auto-obsoleted due to no activity on 2024/12/06 15:04
linux-4.14 INFO: task hung in exit_signals 1 1 2206d 2206d 0/1 auto-closed as invalid on 2020/03/16 09:13
linux-5.15 INFO: task hung in exit_signals origin:upstream 1 C 39 3d12h 69d 0/3 upstream: reported C repro on 2025/09/23 04:44

Sample crash report:
INFO: task udevd:4309 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:26288 pid:4309  ppid:3638   flags:0x00004002
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
 percpu_rwsem_wait+0x2bd/0x300 kernel/locking/percpu-rwsem.c:162
 __percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
 percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
 cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
 exit_signals+0x3c0/0x4f0 kernel/signal.c:2963
 do_exit+0x578/0x2400 kernel/exit.c:827
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 __do_sys_exit_group kernel/exit.c:1033 [inline]
 __se_sys_exit_group kernel/exit.c:1031 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
 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: 0033:0x7fb42c6f16c5
RSP: 002b:00007ffc648242f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00005627ec702990 RCX: 00007fb42c6f16c5
RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
RBP: 00005627ec6de910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc64824340 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
INFO: task udevd:4376 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:26464 pid:4376  ppid:3638   flags:0x00004002
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
 percpu_rwsem_wait+0x2bd/0x300 kernel/locking/percpu-rwsem.c:162
 __percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
 percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
 cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
 exit_signals+0x3c0/0x4f0 kernel/signal.c:2963
 do_exit+0x578/0x2400 kernel/exit.c:827
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 __do_sys_exit_group kernel/exit.c:1033 [inline]
 __se_sys_exit_group kernel/exit.c:1031 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
 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: 0033:0x7fb42c6f16c5
RSP: 002b:00007ffc648242f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00005627ec702f80 RCX: 00007fb42c6f16c5
RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
RBP: 00005627ec6de910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc64824340 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:4398 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:24832 pid:4398  ppid:4294   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
 percpu_rwsem_wait+0x2bd/0x300 kernel/locking/percpu-rwsem.c:162
 __percpu_down_read+0xda/0x120 kernel/locking/percpu-rwsem.c:177
 percpu_down_read include/linux/percpu-rwsem.h:65 [inline]
 cgroup_threadgroup_change_begin include/linux/cgroup-defs.h:748 [inline]
 exit_signals+0x3c0/0x4f0 kernel/signal.c:2963
 do_exit+0x578/0x2400 kernel/exit.c:827
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f99cb7857d3
RSP: 002b:00007ffe12e5f668 EFLAGS: 00000202 ORIG_RAX: 000000000000003d
RAX: fffffffffffffe00 RBX: 0000000000001131 RCX: 00007f99cb7857d3
RDX: 0000000040000000 RSI: 00007ffe12e5f67c RDI: 00000000ffffffff
RBP: 00007ffe12e5f67c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
R13: 00007ffe12e5f6e8 R14: 00007ffe12e5f968 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:4403 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22120 pid:4403  ppid:4400   flags:0x00004000
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
 mmap_write_lock include/linux/mmap_lock.h:71 [inline]
 mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
 cpuset_attach+0x284/0x540 kernel/cgroup/cpuset.c:2663
 cgroup_migrate_execute+0x7a3/0xf30 kernel/cgroup/cgroup.c:2662
 cgroup_attach_task+0x558/0x840 kernel/cgroup/cgroup.c:2953
 __cgroup1_procs_write+0x2e0/0x3e0 kernel/cgroup/cgroup-v1.c:522
 cgroup_file_write+0x2f8/0x660 kernel/cgroup/cgroup.c:4100
 kernfs_fop_write_iter+0x3b2/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x44c/0x960 fs/read_write.c:584
 ksys_write+0x143/0x240 fs/read_write.c:637
 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: 0033:0x7f52cc58e17f
RSP: 002b:00007ffd070fc290 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f52cc58e17f
RDX: 0000000000000001 RSI: 00007ffd070fc2e0 RDI: 0000000000000003
RBP: 00007ffd070fc850 R08: 0000000000000000 R09: 00007ffd070fc0e7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffd070fc2e0 R14: 00007ffd070fc810 R15: 00007ffd070fc850
 </TASK>
INFO: task syz-executor:4413 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21280 pid:4413  ppid:4409   flags:0x00004000
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
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x555/0xaf0 kernel/locking/mutex.c:747
 cgroup_lock include/linux/cgroup.h:442 [inline]
 cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1700
 __cgroup_procs_write+0x73/0x350 kernel/cgroup/cgroup.c:5174
 cgroup_procs_write+0x23/0x40 kernel/cgroup/cgroup.c:5214
 cgroup_file_write+0x2f8/0x660 kernel/cgroup/cgroup.c:4100
 kernfs_fop_write_iter+0x3b2/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x44c/0x960 fs/read_write.c:584
 ksys_write+0x143/0x240 fs/read_write.c:637
 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: 0033:0x7f876498e17f
RSP: 002b:00007ffc056e17a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f876498e17f
RDX: 0000000000000001 RSI: 00007ffc056e17f0 RDI: 0000000000000003
RBP: 00007ffc056e1d60 R08: 0000000000000000 R09: 00007ffc056e15f7
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 00007ffc056e17f0 R14: 00007ffc056e1d20 R15: 00007ffc056e1d60
 </TASK>
INFO: task syz.3.137:4647 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.137       state:D stack:23976 pid:4647  ppid:4410   flags:0x00004000
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
 mmap_write_lock include/linux/mmap_lock.h:71 [inline]
 exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
 __mmput+0x118/0x3c0 kernel/fork.c:1200
 exit_mm+0x1e6/0x2c0 kernel/exit.c:565
 do_exit+0x8c1/0x2400 kernel/exit.c:867
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 __do_sys_exit_group kernel/exit.c:1033 [inline]
 __se_sys_exit_group kernel/exit.c:1031 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
 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: 0033:0x7fc576b8f6c9
RSP: 002b:00007ffdee694a08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc576b8f6c9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffdee694a6c R08: 00000005ee694aff R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000002
R13: 00000000000927c0 R14: 00000000000261a6 R15: 00007ffdee694ac0
 </TASK>
INFO: task syz.0.138:4648 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.138       state:D stack:25192 pid:4648  ppid:4401   flags:0x00004000
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
 mmap_write_lock include/linux/mmap_lock.h:71 [inline]
 exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
 __mmput+0x118/0x3c0 kernel/fork.c:1200
 exit_mm+0x1e6/0x2c0 kernel/exit.c:565
 do_exit+0x8c1/0x2400 kernel/exit.c:867
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 __do_sys_exit_group kernel/exit.c:1033 [inline]
 __se_sys_exit_group kernel/exit.c:1031 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
 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: 0033:0x7f99cb78f6c9
RSP: 002b:00007ffe12e5f478 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f99cb78f6c9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffe12e5f4dc R08: 0000000512e5f56f R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000070
R13: 00000000000927c0 R14: 0000000000026207 R15: 00007ffe12e5f530
 </TASK>

Showing all locks held in the system:
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
1 lock held by klogd/3627:
 #0: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
1 lock held by dhcpcd/3933:
 #0: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: copy_process+0x248b/0x4020 kernel/fork.c:2446
2 locks held by getty/4029:
 #0: ffff88802ffc9098 (&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
1 lock held by udevd/4309:
 #0: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
1 lock held by udevd/4376:
 #0: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
1 lock held by syz-executor/4398:
 #0: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: do_exit+0x578/0x2400 kernel/exit.c:827
7 locks held by syz-executor/4403:
 #0: ffff88807b008460 (sb_writers#11){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
 #1: ffff88807a46f088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343
 #2: ffffffff8cb536e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline]
 #2: ffffffff8cb536e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1700
 #3: ffffffff8c9c7b30 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2476 [inline]
 #3: ffffffff8c9c7b30 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x183/0x600 kernel/cgroup/cgroup.c:2982
 #4: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2478 [inline]
 #4: ffffffff8cb538d0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x199/0x600 kernel/cgroup/cgroup.c:2982
 #5: ffffffff8cb61d68 (cpuset_mutex){+.+.}-{3:3}, at: cpuset_attach+0xac/0x540 kernel/cgroup/cpuset.c:2647
 #6: ffff888025a39058 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
 #6: ffff888025a39058 (&mm->mmap_lock){++++}-{3:3}, at: mpol_rebind_mm+0xbe/0x370 mm/mempolicy.c:386
2 locks held by syz-executor/4405:
 #0: ffffffff8cbc5010 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:593 [inline]
 #0: ffffffff8cbc5010 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline]
 #0: ffffffff8cbc5010 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x2a9/0x15c0 kernel/fork.c:1590
 #1: ffff888025a3d3d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #1: ffff888025a3d3d8 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:594 [inline]
 #1: ffff888025a3d3d8 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1541 [inline]
 #1: ffff888025a3d3d8 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x2c3/0x15c0 kernel/fork.c:1590
1 lock held by udevd/4411:
 #0: ffff888025a3c4d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #0: ffff888025a3c4d8 (&mm->mmap_lock){++++}-{3:3}, at: __vm_munmap+0x141/0x290 mm/mmap.c:2933
3 locks held by syz-executor/4413:
 #0: ffff88807bc8e460 (sb_writers#10){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
 #1: ffff888073bea888 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343
 #2: ffffffff8cb536e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_lock include/linux/cgroup.h:442 [inline]
 #2: ffffffff8cb536e8 (cgroup_mutex){+.+.}-{3:3}, at: cgroup_kn_lock_live+0xee/0x230 kernel/cgroup/cgroup.c:1700
2 locks held by kworker/u4:7/4566:
 #0: ffff8880b8f3aad8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537
 #1: ffff8880b8f27848 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x312/0x6d0 kernel/sched/psi.c:987
1 lock held by syz.3.137/4647:
 #0: ffff88802e84a6d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
 #0: ffff88802e84a6d8 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258
1 lock held by syz.0.138/4648:
 #0: ffff8880270ff1d8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock include/linux/mmap_lock.h:71 [inline]
 #0: ffff8880270ff1d8 (&mm->mmap_lock){++++}-{3:3}, at: exit_mmap+0x20f/0x8e0 mm/mmap.c:3258

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

NMI backtrace for cpu 0
CPU: 0 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2933 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: phy13 ieee80211_iface_work
RIP: 0010:cfg80211_bss_update+0x1e28/0x2250 net/wireless/scan.c:1942
Code: ff e8 ac 6d 0a f8 48 ff cb 74 07 e8 c2 69 0a f8 eb 0d e8 bb 69 0a f8 4c 89 f7 e8 b3 c4 00 00 4c 89 ef e8 ab 7d ab 00 45 31 f6 <4c> 89 f0 48 81 c4 f8 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8
RSP: 0018:ffffc9000cd37350 EFLAGS: 00000246
RAX: d263556ee822cd00 RBX: 0000000000000000 RCX: d263556ee822cd00
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: ffffffff8adef760
RBP: dffffc0000000000 R08: dffffc0000000000 R09: fffffbfff215c456
R10: fffffbfff215c456 R11: 1ffffffff215c455 R12: 0000000000000000
R13: ffffc9000cd37560 R14: ffff88807a46e800 R15: ffff88805cd28150
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0083b7010 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 cfg80211_inform_single_bss_frame_data net/wireless/scan.c:2512 [inline]
 cfg80211_inform_bss_frame_data+0x9f4/0x1370 net/wireless/scan.c:2545
 ieee80211_bss_info_update+0x734/0xbc0 net/mac80211/scan.c:190
 ieee80211_rx_bss_info net/mac80211/ibss.c:1120 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x17b4/0x2b10 net/mac80211/ibss.c:1638
 ieee80211_iface_process_skb net/mac80211/iface.c:1671 [inline]
 ieee80211_iface_work+0x726/0xc80 net/mac80211/iface.c:1725
 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 (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/10 05:48 linux-6.1.y f6e38ae624cf 4e1406b4 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in exit_signals
2025/10/08 14:07 linux-6.1.y 882efbdd9d34 7e2882b3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in exit_signals
2025/09/24 15:37 linux-6.1.y 363a599da6d9 0abd0691 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in exit_signals
2025/10/07 10:29 linux-6.1.y 882efbdd9d34 8ef35d49 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: task hung in exit_signals
* Struck through repros no longer work on HEAD.