syzbot


INFO: task hung in ext4_fallocate

Status: auto-closed as invalid on 2019/07/02 10:28
Reported-by: syzbot+b6ddfbbf6c5908405fd9@syzkaller.appspotmail.com
First crash: 1933d, last: 1933d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ext4_fallocate ext4 C 1 2028d 2026d 11/26 fixed on 2018/11/12 21:25
upstream INFO: task hung in ext4_fallocate (2) ext4 1 527d 527d 0/26 auto-obsoleted due to no activity on 2023/02/10 19:26
upstream INFO: task hung in ext4_fallocate (3) ext4 1 373d 373d 0/26 auto-obsoleted due to no activity on 2023/07/11 11:25

Sample crash report:
ip6_tunnel: 6tnl0 xmit: Local address not yet configured!
ip6_tunnel: 6tnl0 xmit: Local address not yet configured!
ip6_tunnel: 6tnl0 xmit: Local address not yet configured!
ip6_tunnel: 6tnl0 xmit: Local address not yet configured!
INFO: task syz-executor0:32027 blocked for more than 140 seconds.
      Not tainted 4.9.148+ #2
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D28960 32027   2115 0x00000004
 ffff8801cc502f80 ffff8801a305a680 ffff8801db721000 ffff8801cb33c740
 ffff8801db721018 ffff88019cf2fb90 ffffffff82802706 dffffc0000000000
 ffff88019cf2fb68 ffffffff81206e91 00ffffff8280d84f ffff8801db7218f0
Call Trace:
 [<ffffffff82803c92>] schedule+0x92/0x1c0 kernel/sched/core.c:3553
 [<ffffffff8280dab3>] __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:526 [inline]
 [<ffffffff8280dab3>] rwsem_down_write_failed+0x3a3/0x750 kernel/locking/rwsem-xadd.c:555
 [<ffffffff81b764b7>] call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
 [<ffffffff8280c85c>] __down_write arch/x86/include/asm/rwsem.h:125 [inline]
 [<ffffffff8280c85c>] down_write+0x5c/0xa0 kernel/locking/rwsem.c:54
 [<ffffffff8178de79>] inode_lock include/linux/fs.h:768 [inline]
 [<ffffffff8178de79>] ext4_fallocate+0x349/0x1ee0 fs/ext4/extents.c:4974
 [<ffffffff81502ac7>] vfs_fallocate+0x407/0x6a0 fs/open.c:329
 [<ffffffff815059e2>] SYSC_fallocate fs/open.c:352 [inline]
 [<ffffffff815059e2>] SyS_fallocate+0x52/0x90 fs/open.c:346
 [<ffffffff810056bd>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
 [<ffffffff82812993>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131b9bb>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131b9bb>] watchdog+0x11b/0xa40 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe89b>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/1902:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff8156ea38>] __fdget_pos+0xa8/0xd0 fs/file.c:781
2 locks held by getty/2030:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82810a83>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d36c5e>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
1 lock held by syz-executor5/16385:
 #0:  (&sig->cred_guard_mutex){+.+.+.}, at: [<ffffffff815226a5>] prepare_bprm_creds+0x55/0x120 fs/exec.c:1369
1 lock held by syz-executor3/19583:
 #0:  (&sig->cred_guard_mutex){+.+.+.}, at: [<ffffffff815226a5>] prepare_bprm_creds+0x55/0x120 fs/exec.c:1369
2 locks held by syz-executor0/32027:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff81502a69>] sb_start_write include/linux/fs.h:1575 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff81502a69>] vfs_fallocate+0x3a9/0x6a0 fs/open.c:328
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<ffffffff8178de79>] inode_lock include/linux/fs.h:768 [inline]
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<ffffffff8178de79>] ext4_fallocate+0x349/0x1ee0 fs/ext4/extents.c:4974
2 locks held by syz-executor0/32038:
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff815773cf>] sb_start_write include/linux/fs.h:1575 [inline]
 #0:  (sb_writers#4){.+.+.+}, at: [<ffffffff815773cf>] mnt_want_write+0x3f/0xb0 fs/namespace.c:391
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<ffffffff81504b30>] inode_lock include/linux/fs.h:768 [inline]
 #1:  (&sb->s_type->i_mutex_key#9){++++++}, at: [<ffffffff81504b30>] do_truncate2+0x130/0x210 fs/open.c:61

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.148+ #2
 ffff8801d9907cd0 ffffffff81b44d01 0000000000000000 0000000000000000
 0000000000000000 ffffffff81097301 00000000003ffdb7 ffff8801d9907d08
 ffffffff81b4ff8c 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<ffffffff81b44d01>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b44d01>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff81b4ff8c>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4ff14>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<ffffffff81097494>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131be97>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131be97>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131be97>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131be97>] watchdog+0x5f7/0xa40 kernel/hung_task.c:239
 [<ffffffff81141e38>] kthread+0x278/0x310 kernel/kthread.c:211
 [<ffffffff82812b5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff82811592

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/01/03 10:28 https://android.googlesource.com/kernel/common android-4.9 dc64ace4cb70 06a2b89f .config console log report ci-android-49-kasan-gce-root
* Struck through repros no longer work on HEAD.