syzbot


INFO: task hung in do_truncate

Status: auto-obsoleted due to no activity on 2023/07/17 23:13
Reported-by: syzbot+db0b430ffe679ed8c2dc@syzkaller.appspotmail.com
First crash: 392d, last: 392d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in do_truncate (2) 1 240d 240d 0/3 auto-obsoleted due to no activity on 2023/11/27 08:00
upstream INFO: task hung in do_truncate (2) fs C done done 14 83d 1404d 0/26 upstream: reported C repro on 2020/06/11 04:48
upstream INFO: task hung in do_truncate ext4 C 7 1977d 2141d 0/26 closed as dup on 2018/09/08 15:38

Sample crash report:
INFO: task syz-executor.3:4517 blocked for more than 143 seconds.
      Not tainted 5.15.103-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:    0 pid: 4517 ppid:  4103 flags:0x00000009
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5023 [inline]
 __schedule+0xfcc/0x1f1c kernel/sched/core.c:6369
 schedule+0x11c/0x1c8 kernel/sched/core.c:6452
 rwsem_down_write_slowpath+0xca8/0x1340 kernel/locking/rwsem.c:1157
 __down_write_common kernel/locking/rwsem.c:1284 [inline]
 __down_write kernel/locking/rwsem.c:1293 [inline]
 down_write+0x25c/0x260 kernel/locking/rwsem.c:1542
 inode_lock include/linux/fs.h:787 [inline]
 do_truncate+0x1ac/0x28c fs/open.c:63
 handle_truncate fs/namei.c:3195 [inline]
 do_open fs/namei.c:3542 [inline]
 path_openat+0x20e8/0x26f0 fs/namei.c:3672
 do_filp_open+0x1a8/0x3b4 fs/namei.c:3699
 do_sys_openat2+0x128/0x3d8 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_openat fs/open.c:1243 [inline]
 __se_sys_openat fs/open.c:1238 [inline]
 __arm64_sys_openat+0x1f0/0x240 fs/open.c:1238
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffff800014b92620 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:268
2 locks held by getty/3734:
 #0: ffff0000d322b098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
 #1: ffff80001a3ab2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1200 drivers/tty/n_tty.c:2147
3 locks held by kworker/u4:7/4386:
2 locks held by kworker/u4:9/4404:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x66c/0x14b8 kernel/workqueue.c:2279
 #1: ffff80001f727c00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x14b8 kernel/workqueue.c:2281
2 locks held by syz-executor.3/4517:
 #0: ffff0000db66e460 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377
 #1: ffff0000df72f240 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff0000df72f240 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: do_truncate+0x1ac/0x28c fs/open.c:63
3 locks held by syz-executor.3/4521:
2 locks held by kworker/u4:11/5143:
 #0: ffff0000c0029138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x66c/0x14b8 kernel/workqueue.c:2279
 #1: ffff800029157c00 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x14b8 kernel/workqueue.c:2281
2 locks held by syz-executor.5/6986:
1 lock held by syz-executor.3/6992:
 #0: ffff0001b4814d18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:475 [inline]
 #0: ffff0001b4814d18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1325 [inline]
 #0: ffff0001b4814d18 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1620 [inline]
 #0: ffff0001b4814d18 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x328/0x1f1c kernel/sched/core.c:6283
2 locks held by syz-executor.2/6997:

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


Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/03/19 23:12 linux-5.15.y 8020ae3c051d 7939252e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in do_truncate
* Struck through repros no longer work on HEAD.