syzbot


INFO: task hung in lookup_slow

Status: auto-obsoleted due to no activity on 2023/08/15 05:05
Reported-by: syzbot+a792a057e0af55f2c2d9@syzkaller.appspotmail.com
First crash: 604d, last: 599d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in lookup_slow (2) fs 2 1927d 1939d 0/28 auto-closed as invalid on 2019/11/26 02:54
upstream INFO: task hung in lookup_slow exfat 148 2148d 2441d 0/28 closed as dup on 2018/09/08 15:36
linux-6.1 INFO: task hung in lookup_slow 15 60d 236d 0/3 upstream: reported on 2024/04/14 05:59
linux-5.15 INFO: task hung in lookup_slow (2) origin:upstream C 48 1d18h 235d 0/3 upstream: reported C repro on 2024/04/15 04:02
upstream INFO: task hung in lookup_slow (3) fs C unreliable 1692 21h11m 756d 0/28 upstream: reported C repro on 2022/11/11 00:21
android-49 INFO: task hung in lookup_slow syz 36 1953d 2062d 0/3 public: reported syz repro on 2019/04/14 08:51
linux-4.14 INFO: task hung in lookup_slow C error 1 825d 855d 0/1 upstream: reported C repro on 2022/08/03 08:46
linux-4.19 INFO: task hung in lookup_slow 1 1635d 1635d 0/1 auto-closed as invalid on 2020/10/13 00:17

Sample crash report:
INFO: task syz-executor.2:8039 blocked for more than 144 seconds.
      Not tainted 5.15.107-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:    0 pid: 8039 ppid:  4112 flags:0x00000001
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0xf10/0x1e38 kernel/sched/core.c:6372
 schedule+0x11c/0x1c8 kernel/sched/core.c:6455
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:6514
 rwsem_down_read_slowpath+0x5b0/0x988 kernel/locking/rwsem.c:1047
 __down_read_common+0x6c/0x2dc kernel/locking/rwsem.c:1231
 __down_read kernel/locking/rwsem.c:1244 [inline]
 down_read+0xc8/0x11c kernel/locking/rwsem.c:1490
 inode_lock_shared include/linux/fs.h:797 [inline]
 lookup_slow+0x50/0x84 fs/namei.c:1675
 walk_component+0x394/0x4cc fs/namei.c:1972
 lookup_last fs/namei.c:2427 [inline]
 path_lookupat+0x13c/0x3d0 fs/namei.c:2451
 filename_lookup+0x1c4/0x4c8 fs/namei.c:2480
 user_path_at_empty+0x5c/0x1a4 fs/namei.c:2853
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0xf8/0x378 fs/stat.c:221
 vfs_fstatat fs/stat.c:243 [inline]
 __do_sys_newfstatat fs/stat.c:411 [inline]
 __se_sys_newfstatat fs/stat.c:405 [inline]
 __arm64_sys_newfstatat+0x110/0x194 fs/stat.c:405
 __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
INFO: task syz-executor.2:8040 blocked for more than 144 seconds.
      Not tainted 5.15.107-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2  state:D stack:    0 pid: 8040 ppid:  4112 flags:0x00000001
Call trace:
 __switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
 context_switch kernel/sched/core.c:5026 [inline]
 __schedule+0xf10/0x1e38 kernel/sched/core.c:6372
 schedule+0x11c/0x1c8 kernel/sched/core.c:6455
 xlog_grant_head_wait+0x390/0xa88 fs/xfs/xfs_log.c:256
 xlog_grant_head_check+0x218/0x3d8
 xfs_log_reserve+0x384/0xc1c fs/xfs/xfs_log.c:464
 xfs_trans_reserve+0x1e8/0x5a4 fs/xfs/xfs_trans.c:197
 xfs_trans_alloc+0x4c4/0xaa4 fs/xfs/xfs_trans.c:288
 xfs_trans_alloc_icreate+0xc8/0x290 fs/xfs/xfs_trans.c:1102
 xfs_create+0x578/0xfec fs/xfs/xfs_inode.c:1018
 xfs_generic_create+0x390/0xb70 fs/xfs/xfs_iops.c:197
 xfs_vn_create+0x44/0x58 fs/xfs/xfs_iops.c:275
 lookup_open fs/namei.c:3392 [inline]
 open_last_lookups fs/namei.c:3462 [inline]
 path_openat+0xec0/0x26f0 fs/namei.c:3669
 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: ffff800014aa1660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:268
2 locks held by getty/3738:
 #0: ffff0000d3e4a098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
 #1: ffff80001a30b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1200 drivers/tty/n_tty.c:2147
2 locks held by kworker/u4:16/5673:
1 lock held by syz-executor.2/8039:
 #0: ffff000123b46480 (&inode->i_sb->s_type->i_mutex_dir_key#2){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:797 [inline]
 #0: ffff000123b46480 (&inode->i_sb->s_type->i_mutex_dir_key#2){++++}-{3:3}, at: lookup_slow+0x50/0x84 fs/namei.c:1675
3 locks held by syz-executor.2/8040:
 #0: ffff000126f52460 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377
 #1: ffff000123b46480 (&inode->i_sb->s_type->i_mutex_dir_key#2){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff000123b46480 (&inode->i_sb->s_type->i_mutex_dir_key#2){++++}-{3:3}, at: open_last_lookups fs/namei.c:3459 [inline]
 #1: ffff000123b46480 (&inode->i_sb->s_type->i_mutex_dir_key#2){++++}-{3:3}, at: path_openat+0x63c/0x26f0 fs/namei.c:3669
 #2: ffff000126f52650 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_icreate+0xc8/0x290 fs/xfs/xfs_trans.c:1102
1 lock held by syz-executor.4/11205:

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Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/04/17 05:05 linux-5.15.y 4fdad925aa1a ec410564 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in lookup_slow
2023/04/12 01:03 linux-5.15.y d86dfc4d95cd 49faf98d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: task hung in lookup_slow
* Struck through repros no longer work on HEAD.