syzbot


INFO: task hung in search_by_key

Status: upstream: reported on 2025/06/26 20:06
Reported-by: syzbot+63fea8b795fc3ee36e62@syzkaller.appspotmail.com
First crash: 6d04h, last: 1d22h

Sample crash report:
INFO: task syz.8.1049:10641 blocked for more than 146 seconds.
      Not tainted 6.1.142-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.1049      state:D stack:0     pid:10641 ppid:8114   flags:0x0000000d
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 schedule+0xc4/0x170 kernel/sched/core.c:6637
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6696
 __mutex_lock_common+0xad4/0x1f38 kernel/locking/mutex.c:679
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x38/0x44 kernel/locking/mutex.c:799
 reiserfs_write_lock_nested+0x68/0xd8 fs/reiserfs/lock.c:78
 reiserfs_cond_resched fs/reiserfs/reiserfs.h:849 [inline]
 search_by_key+0x878/0x3838 fs/reiserfs/stree.c:712
 reiserfs_update_sd_size+0x1a8/0xb48 fs/reiserfs/inode.c:1455
 reiserfs_update_sd fs/reiserfs/reiserfs.h:3099 [inline]
 indirect2direct+0x520/0x87c fs/reiserfs/tail_conversion.c:299
 maybe_indirect_to_direct fs/reiserfs/stree.c:1587 [inline]
 reiserfs_cut_from_item+0x76c/0x1a58 fs/reiserfs/stree.c:1694
 reiserfs_do_truncate+0x738/0x1020 fs/reiserfs/stree.c:1973
 reiserfs_truncate_file+0x5c0/0xaf4 fs/reiserfs/inode.c:2310
 reiserfs_file_release+0x710/0x894 fs/reiserfs/file.c:109
 __fput+0x1bc/0x7c0 fs/file_table.c:320
 ____fput+0x20/0x30 fs/file_table.c:348
 task_work_run+0x1ec/0x270 kernel/task_work.c:203
 get_signal+0x1120/0x1310 kernel/signal.c:2648
 do_signal arch/arm64/kernel/signal.c:1081 [inline]
 do_notify_resume+0x340/0x2b0c arch/arm64/kernel/signal.c:1134
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x98/0x138 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
INFO: task syz.8.1049:10643 blocked for more than 146 seconds.
      Not tainted 6.1.142-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.1049      state:D stack:0     pid:10643 ppid:8114   flags:0x00000009
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 schedule+0xc4/0x170 kernel/sched/core.c:6637
 io_schedule+0x84/0x154 kernel/sched/core.c:8797
 folio_wait_bit_common+0x56c/0x9c4 mm/filemap.c:1324
 __folio_lock mm/filemap.c:1687 [inline]
 folio_lock include/linux/pagemap.h:974 [inline]
 __filemap_get_folio+0x4ec/0xab0 mm/filemap.c:1959
 pagecache_get_page+0x3c/0x16c mm/folio-compat.c:110
 find_or_create_page include/linux/pagemap.h:646 [inline]
 grab_cache_page include/linux/pagemap.h:778 [inline]
 convert_tail_for_hole fs/reiserfs/inode.c:592 [inline]
 reiserfs_get_block+0x2248/0x3524 fs/reiserfs/inode.c:921
 __block_write_begin_int+0x34c/0x13b8 fs/buffer.c:1991
 __block_write_begin+0x7c/0xa0 fs/buffer.c:2041
 reiserfs_write_begin+0x328/0x71c fs/reiserfs/inode.c:2775
 generic_cont_expand_simple+0x12c/0x1fc fs/buffer.c:2347
 reiserfs_setattr+0x564/0xf7c fs/reiserfs/inode.c:3305
 notify_change+0xb0c/0xdcc fs/attr.c:499
 do_truncate+0x178/0x1f0 fs/open.c:65
 vfs_truncate+0x23c/0x2b0 fs/open.c:111
 do_sys_truncate+0xe8/0x1b0 fs/open.c:134
 __do_sys_truncate fs/open.c:146 [inline]
 __se_sys_truncate fs/open.c:144 [inline]
 __arm64_sys_truncate+0x5c/0x70 fs/open.c:144
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015257770 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015257f90 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffff800015256e00 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by getty/4061:
 #0: ffff0000d622f098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001ce602f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xf9c drivers/tty/n_tty.c:2198
2 locks held by kworker/u4:6/4391:
 #0: ffff00019f719198 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:537 [inline]
 #0: ffff00019f719198 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1355 [inline]
 #0: ffff00019f719198 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1645 [inline]
 #0: ffff00019f719198 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x2b8/0x1b2c kernel/sched/core.c:6477
 #1: ffff00019f705bc8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x380/0x608 kernel/sched/psi.c:999
4 locks held by kworker/0:1/8616:
 #0: ffff0000c0021138 ((wq_completion)events_long){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
 #1: ffff800021707c20 ((work_completion)(&(&sbi->old_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
 #2: ffff0000d31a20e0 (&type->s_umount_key#99){++++}-{3:3}, at: flush_old_commits+0xc8/0x29c fs/reiserfs/super.c:97
 #3: ffff0000d2bbc090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock+0x7c/0xe8 fs/reiserfs/lock.c:27
3 locks held by kworker/u4:27/10005:
2 locks held by syz.8.1049/10641:
 #0: ffff0000dfbef7f8 (&ei->tailpack){+.+.}-{3:3}, at: reiserfs_file_release+0xc8/0x894 fs/reiserfs/file.c:41
 #1: ffff0000d2bbc090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock_nested+0x68/0xd8 fs/reiserfs/lock.c:78
3 locks held by syz.8.1049/10643:
 #0: ffff0000d31a2460 (sb_writers#25){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:393
 #1: ffff0000dfbefa20 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff0000dfbefa20 (&sb->s_type->i_mutex_key#32){+.+.}-{3:3}, at: do_truncate+0x164/0x1f0 fs/open.c:63
 #2: ffff0000d2bbc090 (&sbi->lock){+.+.}-{3:3}, at: reiserfs_write_lock_nested+0x68/0xd8 fs/reiserfs/lock.c:78
1 lock held by syz.9.1309/12130:
1 lock held by syz.4.1313/12161:
2 locks held by dhcpcd-run-hook/12164:

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


Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/01 02:03 linux-6.1.y 7e69c33e4858 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in search_by_key
2025/06/26 20:05 linux-6.1.y 58485ff1a74f 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in search_by_key
* Struck through repros no longer work on HEAD.