syzbot


INFO: task hung in kernfs_dop_revalidate

Status: upstream: reported syz repro on 2022/06/22 02:35
Reported-by: syzbot+41424c58d8613bce38c0@syzkaller.appspotmail.com
First crash: 105d, last: 75d

Cause bisection: introduced by (bisect log) [merge commit]:
commit ed4643521e6af8ab8ed1e467630a85884d2696cf
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu Mar 24 01:37:22 2022 +0000

  Merge tag 'arm-dt-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc

Crash: SYZFATAL: executor failed NUM times: executor NUM: failed to write control pipe: write |NUM: broken pipe (log)
Repro: syz .config

Fix bisection: the fix commit could be any of (bisect log):
  f0ec9c65a8d6 Merge tag 'char-misc-5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
  3cc40a443a04 Merge tag 'nios2_fixes_v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in kernfs_dop_revalidate 1 1154d 1154d 0/1 auto-closed as invalid on 2019/12/01 15:25

Sample crash report:
INFO: task udevd:2979 blocked for more than 147 seconds.
      Not tainted 5.19.0-rc2-syzkaller-00147-gf0ec9c65a8d6 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:26640 pid: 2979 ppid:     1 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5116 [inline]
 __schedule+0xa00/0x4b30 kernel/sched/core.c:6428
 schedule+0xd2/0x1f0 kernel/sched/core.c:6500
 rwsem_down_read_slowpath+0x5b9/0xb00 kernel/locking/rwsem.c:1077
 __down_read_common kernel/locking/rwsem.c:1242 [inline]
 __down_read kernel/locking/rwsem.c:1251 [inline]
 down_read+0xe2/0x440 kernel/locking/rwsem.c:1491
 kernfs_dop_revalidate+0xec/0x600 fs/kernfs/dir.c:1098
 d_revalidate fs/namei.c:848 [inline]
 d_revalidate fs/namei.c:845 [inline]
 lookup_fast+0x385/0x6d0 fs/namei.c:1662
 walk_component+0xcf/0x6a0 fs/namei.c:2010
 link_path_walk.part.0+0x7ef/0xf70 fs/namei.c:2341
 link_path_walk fs/namei.c:2265 [inline]
 path_lookupat+0xc8/0x860 fs/namei.c:2492
 filename_lookup+0x1c6/0x590 fs/namei.c:2522
 user_path_at_empty+0x42/0x60 fs/namei.c:2895
 do_readlinkat+0xcd/0x2f0 fs/stat.c:456
 __do_sys_readlink fs/stat.c:489 [inline]
 __se_sys_readlink fs/stat.c:486 [inline]
 __x64_sys_readlink+0x74/0xb0 fs/stat.c:486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7fb1d2b27277
RSP: 002b:00007ffda1230de8 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffda1230df8 RCX: 00007fb1d2b27277
RDX: 0000000000000400 RSI: 00007ffda1230df8 RDI: 00007ffda12312d8
RBP: 0000000000000400 R08: 00000000007fffff R09: 0000563248ae65a0
R10: 00007fb1d2bb4fc0 R11: 0000000000000246 R12: 00007ffda12312d8
R13: 00007ffda1231248 R14: 0000563248ad0910 R15: 0000000000000000
 </TASK>
INFO: task syz-executor.3:3686 blocked for more than 156 seconds.
      Not tainted 5.19.0-rc2-syzkaller-00147-gf0ec9c65a8d6 #0

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2022/06/18 02:33 upstream f0ec9c65a8d6 cb58b3b2 .config log report syz INFO: task hung in kernfs_dop_revalidate
ci-upstream-kasan-gce-root 2022/06/18 00:27 upstream f0ec9c65a8d6 cb58b3b2 .config log report info INFO: task hung in kernfs_dop_revalidate
* Struck through repros no longer work on HEAD.