syzbot


INFO: task hung in blkdev_issue_flush

Status: fixed on 2019/12/02 18:09
Reported-by: syzbot+b8dab3b2459def923263@syzkaller.appspotmail.com
Fix commit: 76cf93f04c3d hwmon: (acpi_power_meter) Change log level for 'unsafe software power cap'
First crash: 1788d, last: 1788d
Fix bisection: fixed by (bisect log) :
commit 76cf93f04c3dedc29660fed2c26fdbc21f604725
Author: Wang Shenran <shenran268@gmail.com>
Date: Wed Jul 24 08:01:10 2019 +0000

  hwmon: (acpi_power_meter) Change log level for 'unsafe software power cap'

  
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-44 INFO: task hung in blkdev_issue_flush 7 2147d 2258d 0/2 auto-closed as invalid on 2019/02/22 12:34
android-414 INFO: task hung in blkdev_issue_flush 1 1740d 1740d 0/1 auto-closed as invalid on 2019/12/17 04:03
android-49 INFO: task hung in blkdev_issue_flush 63 2141d 2277d 0/3 auto-closed as invalid on 2019/02/22 14:39
upstream INFO: task hung in blkdev_issue_flush block 12 1926d 2229d 0/26 closed as dup on 2019/02/16 05:19
upstream INFO: task hung in blkdev_issue_flush (2) block C done error 3 1629d 1787d 15/26 fixed on 2020/06/30 18:57

Sample crash report:
audit: type=1400 audit(1562047191.513:36): avc:  denied  { map } for  pid=7755 comm="syz-executor084" path="/root/syz-executor084409957" dev="sda1" ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
block nbd0: shutting down sockets
INFO: task syz-executor084:7757 blocked for more than 140 seconds.
      Not tainted 4.19.56 #28
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor084 D28928  7757   7753 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x80d/0x1c70 kernel/sched/core.c:3474
 schedule+0x92/0x1c0 kernel/sched/core.c:3518
 schedule_timeout+0x8c8/0xfc0 kernel/time/timer.c:1780
 io_schedule_timeout+0x26/0x80 kernel/sched/core.c:5129
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common_io kernel/sched/completion.c:121 [inline]
 wait_for_completion_io+0x29c/0x440 kernel/sched/completion.c:169
 submit_bio_wait+0x11d/0x1c0 block/bio.c:931
 blkdev_issue_flush+0x20b/0x300 block/blk-flush.c:553
 blkdev_fsync+0x95/0xd0 fs/block_dev.c:647
 vfs_fsync_range+0x141/0x230 fs/sync.c:197
 vfs_fsync fs/sync.c:211 [inline]
 do_fsync+0x54/0xa0 fs/sync.c:221
 __do_sys_fdatasync fs/sync.c:234 [inline]
 __se_sys_fdatasync fs/sync.c:232 [inline]
 __x64_sys_fdatasync+0x36/0x50 fs/sync.c:232
 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x449789
Code: Bad RIP value.
RSP: 002b:00007fba8e1fcce8 EFLAGS: 00000246 ORIG_RAX: 000000000000004b
RAX: ffffffffffffffda RBX: 00000000006dac58 RCX: 0000000000449789
RDX: 0000000000449789 RSI: 0000000000000000 RDI: 0000000000000009
RBP: 00000000006dac50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac5c
R13: 00007ffc01d74a5f R14: 00007fba8e1fd9c0 R15: 20c49ba5e353f7cf

Showing all locks held in the system:
1 lock held by khungtaskd/1029:
 #0: 00000000eca0e8c4 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4435
1 lock held by rsyslogd/7604:
2 locks held by getty/7727:
 #0: 00000000f0204946 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 0000000015efb458 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7728:
 #0: 00000000cb5b1147 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 00000000560cdf4e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7729:
 #0: 000000007bddcd1c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 000000001997f524 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7730:
 #0: 0000000030ce0a67 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 00000000cf60cb1e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7731:
 #0: 000000007a208e32 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 0000000016a3b44d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7732:
 #0: 00000000540a4f7b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 000000009493c284 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7733:
 #0: 0000000098989f02 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 00000000a7619b96 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154

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

NMI backtrace for cpu 0
CPU: 0 PID: 1029 Comm: khungtaskd Not tainted 4.19.56 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x9df/0xee0 kernel/hung_task.c:287
 kthread+0x354/0x420 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/07/02 06:06 linux-4.19.y aec3002d07fd cccc4302 .config console log report syz C ci2-linux-4-19
2019/07/02 01:29 linux-4.19.y aec3002d07fd cccc4302 .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.