syzbot


INFO: task hung in call_usermodehelper_exec (3)

Status: auto-obsoleted due to no activity on 2025/07/16 16:50
Subsystems: kernel
[Documentation on labels]
First crash: 206d, last: 183d
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in call_usermodehelper_exec cgroups 1 1 1743d 1743d 0/29 auto-closed as invalid on 2021/04/09 04:38
upstream INFO: task hung in call_usermodehelper_exec (2) cgroups 1 1 1438d 1438d 0/29 closed as invalid on 2022/02/08 09:40

Sample crash report:
INFO: task kworker/1:0:24 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0     state:D stack:25848 pid:24    tgid:24    ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: afs afs_manage_cell_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common+0x2fc/0x4e0 kernel/sched/completion.c:116
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion_state+0x1c/0x40 kernel/sched/completion.c:264
 call_usermodehelper_exec+0x371/0x4d0 kernel/umh.c:457
 call_usermodehelper_keys security/keys/request_key.c:111 [inline]
 call_sbin_request_key+0x784/0xda0 security/keys/request_key.c:196
 construct_key security/keys/request_key.c:247 [inline]
 construct_key_and_link security/keys/request_key.c:519 [inline]
 request_key_and_link+0xeae/0x1370 security/keys/request_key.c:653
 request_key_tag+0x56/0xc0 security/keys/request_key.c:717
 dns_query+0x35f/0x8e0 net/dns_resolver/dns_query.c:128
 afs_dns_query+0x11d/0x390 fs/afs/addr_list.c:258
 afs_update_cell fs/afs/cell.c:420 [inline]
 afs_manage_cell fs/afs/cell.c:806 [inline]
 afs_manage_cell_work+0xe2a/0x1940 fs/afs/cell.c:856
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task jbd2/sda1-8:5174 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:jbd2/sda1-8     state:D stack:26568 pid:5174  tgid:5174  ppid:2      task_flags:0x240040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 io_schedule+0xbf/0x130 kernel/sched/core.c:7742
 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 __wait_on_buffer+0x64/0x70 fs/buffer.c:123
 wait_on_buffer include/linux/buffer_head.h:413 [inline]
 jbd2_journal_commit_transaction+0x382e/0x6830 fs/jbd2/commit.c:808
 kjournald2+0x1f4/0x760 fs/jbd2/journal.c:201
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz-executor:5828 blocked for more than 144 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:23112 pid:5828  tgid:5828  ppid:5826   task_flags:0x440100 flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 io_schedule+0xbf/0x130 kernel/sched/core.c:7742
 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 do_get_write_access+0x93d/0x12a0 fs/jbd2/transaction.c:1092
 jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1241
 __ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x1be/0x320 fs/ext4/inode.c:5892
 __ext4_mark_inode_dirty+0x197/0x870 fs/ext4/inode.c:6066
 ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x1eb/0xe50 fs/fs-writeback.c:2527
 generic_update_time+0xcf/0xf0 fs/inode.c:2064
 inode_update_time fs/inode.c:2077 [inline]
 __file_update_time fs/inode.c:2305 [inline]
 file_update_time+0x17d/0x1c0 fs/inode.c:2335
 ext4_page_mkwrite+0x35e/0x1750 fs/ext4/inode.c:6221
 do_page_mkwrite+0x171/0x380 mm/memory.c:3287
 do_shared_fault mm/memory.c:5594 [inline]
 do_fault mm/memory.c:5656 [inline]
 do_pte_missing+0x29c/0x3fb0 mm/memory.c:4160
 handle_pte_fault mm/memory.c:5997 [inline]
 __handle_mm_fault+0x103d/0x2a40 mm/memory.c:6140
 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6309
 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1337
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7fa9240775ef
RSP: 002b:00007ffc5dc28870 EFLAGS: 00010202
RAX: 00007fa9227b8000 RBX: 0000555568da0280 RCX: 0000000000000007
RDX: 1ffffffff04218ef RSI: 0000555568d962f8 RDI: 0000000000000080
RBP: 00007ffc5dc28b60 R08: 0000555568d96310 R09: 000000000000031d
R10: 0000000000000001 R11: 00007ffc5dc28d70 R12: 00007ffc5dc28bc0
R13: 0000000000000004 R14: 00007ffc5dc288e0 R15: 00007ffc5dc289b0
 </TASK>
INFO: task kworker/u8:4:13936 blocked for more than 144 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:4    state:D stack:24568 pid:13936 tgid:13936 ppid:2      task_flags:0x4248160 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 io_schedule+0xbf/0x130 kernel/sched/core.c:7742
 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 do_get_write_access+0x93d/0x12a0 fs/jbd2/transaction.c:1092
 jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1241
 __ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x1be/0x320 fs/ext4/inode.c:5892
 __ext4_mark_inode_dirty+0x197/0x870 fs/ext4/inode.c:6066
 ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x1eb/0xe50 fs/fs-writeback.c:2527
 mark_inode_dirty_sync include/linux/fs.h:2550 [inline]
 dquot_claim_block include/linux/quotaops.h:363 [inline]
 ext4_da_update_reserve_space+0x2b4/0x750 fs/ext4/inode.c:365
 ext4_es_insert_extent+0xbf1/0x11b0 fs/ext4/extents_status.c:947
 ext4_map_create_blocks fs/ext4/inode.c:570 [inline]
 ext4_map_blocks+0x902/0x1390 fs/ext4/inode.c:706
 mpage_map_one_extent fs/ext4/inode.c:2224 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2277 [inline]
 ext4_do_writepages+0x1a2c/0x3490 fs/ext4/inode.c:2739
 ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:2829
 do_writepages+0x1b2/0x820 mm/page-writeback.c:2656
 __writeback_single_inode+0x160/0xfb0 fs/fs-writeback.c:1680
 writeback_sb_inodes+0x601/0xf90 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2047
 wb_writeback+0x7f3/0xb70 fs/fs-writeback.c:2158
 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
 wb_do_writeback fs/fs-writeback.c:2315 [inline]
 wb_workfn+0x8ca/0xbe0 fs/fs-writeback.c:2343
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz.3.2261:15558 blocked for more than 145 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.2261      state:D stack:26360 pid:15558 tgid:15558 ppid:5838   task_flags:0x440040 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 io_schedule+0xbf/0x130 kernel/sched/core.c:7742
 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 do_get_write_access+0x93d/0x12a0 fs/jbd2/transaction.c:1092
 jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1241
 __ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x1be/0x320 fs/ext4/inode.c:5892
 __ext4_mark_inode_dirty+0x197/0x870 fs/ext4/inode.c:6066
 ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x1eb/0xe50 fs/fs-writeback.c:2527
 generic_update_time+0xcf/0xf0 fs/inode.c:2064
 inode_update_time fs/inode.c:2077 [inline]
 __file_update_time fs/inode.c:2305 [inline]
 file_update_time+0x17d/0x1c0 fs/inode.c:2335
 ext4_page_mkwrite+0x35e/0x1750 fs/ext4/inode.c:6221
 do_page_mkwrite+0x171/0x380 mm/memory.c:3287
 do_shared_fault mm/memory.c:5594 [inline]
 do_fault mm/memory.c:5656 [inline]
 do_pte_missing+0x29c/0x3fb0 mm/memory.c:4160
 handle_pte_fault mm/memory.c:5997 [inline]
 __handle_mm_fault+0x103d/0x2a40 mm/memory.c:6140
 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6309
 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1337
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f315046e2fa
RSP: 002b:00007ffc966f6a60 EFLAGS: 00010202
RAX: 0000001b30bfc000 RBX: 00007f31512e5720 RCX: 0000001b30bfbff8
RDX: 0000001b30820220 RSI: 0000000000000008 RDI: 00007f31512e5720
RBP: ffffffff89d017ad R08: 00007f31507b61f8 R09: 00007f31507a2000
R10: 00007f314f3fb008 R11: 000000000000001a R12: 000000000000001a
R13: 00000000000001c1 R14: ffffffff89d01c02 R15: 00000000000002f5
 </TASK>
INFO: task kworker/u8:3:15561 blocked for more than 145 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:3    state:D stack:26824 pid:15561 tgid:15561 ppid:53     task_flags:0x8040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 io_schedule+0xbf/0x130 kernel/sched/core.c:7742
 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 __wait_on_buffer+0x64/0x70 fs/buffer.c:123
 wait_on_buffer include/linux/buffer_head.h:413 [inline]
 __ext4_find_entry+0x97b/0x11c0 fs/ext4/namei.c:1613
 ext4_lookup_entry fs/ext4/namei.c:1705 [inline]
 ext4_lookup+0x53d/0x730 fs/ext4/namei.c:1773
 lookup_open.isra.0+0x4d7/0x1580 fs/namei.c:3644
 open_last_lookups fs/namei.c:3765 [inline]
 path_openat+0x905/0x2d40 fs/namei.c:4001
 do_filp_open+0x20b/0x470 fs/namei.c:4031
 do_open_execat+0xf9/0x450 fs/exec.c:893
 alloc_bprm+0x2d/0xdd0 fs/exec.c:1518
 kernel_execve+0xb0/0x3b0 fs/exec.c:1993
 call_usermodehelper_exec_async+0x255/0x4c0 kernel/umh.c:109
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz.4.2262:15566 blocked for more than 146 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.2262      state:D stack:28344 pid:15566 tgid:15566 ppid:10489  task_flags:0x440040 flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 io_schedule+0xbf/0x130 kernel/sched/core.c:7742
 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 do_get_write_access+0x93d/0x12a0 fs/jbd2/transaction.c:1092
 jbd2_journal_get_write_access+0x1d6/0x280 fs/jbd2/transaction.c:1241
 __ext4_journal_get_write_access+0x6a/0x340 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x1be/0x320 fs/ext4/inode.c:5892
 __ext4_mark_inode_dirty+0x197/0x870 fs/ext4/inode.c:6066
 ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x1eb/0xe50 fs/fs-writeback.c:2527
 generic_update_time+0xcf/0xf0 fs/inode.c:2064
 inode_update_time fs/inode.c:2077 [inline]
 __file_update_time fs/inode.c:2305 [inline]
 file_update_time+0x17d/0x1c0 fs/inode.c:2335
 ext4_page_mkwrite+0x35e/0x1750 fs/ext4/inode.c:6221
 do_page_mkwrite+0x171/0x380 mm/memory.c:3287
 do_shared_fault mm/memory.c:5594 [inline]
 do_fault mm/memory.c:5656 [inline]
 do_pte_missing+0x29c/0x3fb0 mm/memory.c:4160
 handle_pte_fault mm/memory.c:5997 [inline]
 __handle_mm_fault+0x103d/0x2a40 mm/memory.c:6140
 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6309
 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1337
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x5c/0xc0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7fef0026e2fa
RSP: 002b:00007ffdf6f33b40 EFLAGS: 00010202
RAX: 0000001b32dde000 RBX: 00007fef010e5720 RCX: 0000001b32dddff8
RDX: 0000001b32820220 RSI: 0000000000000008 RDI: 00007fef010e5720
RBP: ffffffff8228b7ad R08: 00007fef005b6038 R09: 00007fef005a2000
R10: 00007feeff9ff008 R11: 0000000000000014 R12: 0000000000000014
R13: 000000000000009e R14: ffffffff8228bb46 R15: 00000000000000b8
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/1:0/24:
 #0: ffff88814cf39148 ((wq_completion)afs){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc900001e7d18 ((work_completion)(&cell->manager)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
1 lock held by khungtaskd/31:
 #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764
2 locks held by kworker/u8:3/53:
 #0: ffff88801b489148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc90000be7d18 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
3 locks held by syz-executor/5828:
 #0: ffff8880329311c8 (vm_lock){++++}-{0:0}, at: do_user_addr_fault+0x452/0x1370 arch/x86/mm/fault.c:1328
 #1: ffff888033f3a518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x171/0x380 mm/memory.c:3287
 #2: ffff888033f3e950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444
1 lock held by syz.0.973/10231:
6 locks held by kworker/u8:4/13936:
 #0: ffff888143e9a148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc9000433fd18 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffff888033f3a0e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:562
 #3: ffff888033f3cb98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1b2/0x820 mm/page-writeback.c:2656
 #4: ffff888033f3e950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444
 #5: ffff888079b2e5d8 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x355/0x1390 fs/ext4/inode.c:705
2 locks held by getty/15365:
 #0: ffff8880316590a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900039ce2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
3 locks held by syz.3.2261/15558:
 #0: ffff888037a9cd08 (vm_lock){++++}-{0:0}, at: do_user_addr_fault+0x452/0x1370 arch/x86/mm/fault.c:1328
 #1: ffff888033f3a518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x171/0x380 mm/memory.c:3287
 #2: ffff888033f3e950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444
1 lock held by kworker/u8:3/15561:
 #0: ffff8880354921f0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:877 [inline]
 #0: ffff8880354921f0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: open_last_lookups fs/namei.c:3764 [inline]
 #0: ffff8880354921f0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: path_openat+0x88a/0x2d40 fs/namei.c:4001
3 locks held by syz.4.2262/15566:
 #0: ffff888028b8e448 (vm_lock){++++}-{0:0}, at: do_user_addr_fault+0x452/0x1370 arch/x86/mm/fault.c:1328
 #1: ffff888033f3a518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x171/0x380 mm/memory.c:3287
 #2: ffff888033f3e950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xf70/0x12c0 kernel/hung_task.c:437
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 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: 7858 Comm: kworker/u8:18 Not tainted 6.15.0-rc2-syzkaller-00087-gcfb2e2c57aef #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:102 [inline]
RIP: 0010:do_raw_spin_unlock+0x87/0x230 kernel/locking/spinlock_debug.c:141
Code: fc ff df 48 c1 ea 03 0f b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 6c 01 00 00 8b 03 85 c0 0f 84 f5 00 00 00 <48> b8 00 00 00 00 00 fc ff df 4c 8d 63 10 4c 89 e2 48 c1 ea 03 80
RSP: 0018:ffffc90003507a88 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffff888063570a00 RCX: ffffffff81986b03
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888063570a00
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffed100c6ae140
R10: ffff888063570a03 R11: 0000000000000000 R12: ffffffff8b3d9c50
R13: ffff888063570a00 R14: ffff888063490d80 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124ab9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056078af09600 CR3: 0000000060540000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:166 [inline]
 _raw_spin_unlock_bh+0x1e/0x30 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_nc_purge_paths+0x1d4/0x3a0 net/batman-adv/network-coding.c:471
 batadv_nc_worker+0x921/0x1030 net/batman-adv/network-coding.c:720
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/17 16:39 upstream cfb2e2c57aef 552876f8 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in call_usermodehelper_exec
2025/03/25 23:22 upstream 2df0c02dab82 89d30d73 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in call_usermodehelper_exec
* Struck through repros no longer work on HEAD.