syzbot has found a reproducer for the following crash on:
HEAD commit: 1656b145 Linux 4.19.40
git tree: linux-4.19.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=1065008ca00000
kernel config:
https://syzkaller.appspot.com/x/.config?x=b4629ebda8b4170b
syz repro:
https://syzkaller.appspot.com/x/repro.syz?x=13748bb4a00000
C reproducer:
https://syzkaller.appspot.com/x/repro.c?x=17b614e8a00000
INFO: task syz-executor407:8036 blocked for more than 140 seconds.
Not tainted 4.19.40 #9
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor407 D28216 8036 8035 0x80000002
Call Trace:
context_switch kernel/sched/core.c:2826 [inline]
__schedule+0x813/0x1d00 kernel/sched/core.c:3474
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x933/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:979
__do_sys_exit_group kernel/exit.c:990 [inline]
__se_sys_exit_group kernel/exit.c:988 [inline]
__x64_sys_exit_group+0x44/0x50 kernel/exit.c:988
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443b78
Code: Bad RIP value.
RSP: 002b:00007ffccc2796a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000443b78
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004c34f0 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d5180 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor407:8160 blocked for more than 140 seconds.
Not tainted 4.19.40 #9
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor407 D28216 8160 8031 0x80000002
Call Trace:
context_switch kernel/sched/core.c:2826 [inline]
__schedule+0x813/0x1d00 kernel/sched/core.c:3474
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x933/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:979
__do_sys_exit_group kernel/exit.c:990 [inline]
__se_sys_exit_group kernel/exit.c:988 [inline]
__x64_sys_exit_group+0x44/0x50 kernel/exit.c:988
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443b78
Code: 64 69 73 63 61 72 64 69 6e 67 20 6d 65 73 73 61 67 65 00 00 00 00 00
00 00 00 41 64 64 65 64 20 6e 65 77 20 65 6e 74 72 79 20 <25> 64 20 66 6f
72 20 66 69 6c 65 20 63 61 63 68 65 2c 20 66 69 6c
RSP: 002b:00007ffccc2796a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000443b78
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004c34f0 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d5180 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor407:8164 blocked for more than 140 seconds.
Not tainted 4.19.40 #9
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor407 D28216 8164 8032 0x80000002
Call Trace:
context_switch kernel/sched/core.c:2826 [inline]
__schedule+0x813/0x1d00 kernel/sched/core.c:3474
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x933/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:979
__do_sys_exit_group kernel/exit.c:990 [inline]
__se_sys_exit_group kernel/exit.c:988 [inline]
__x64_sys_exit_group+0x44/0x50 kernel/exit.c:988
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443b78
Code: 64 69 73 63 61 72 64 69 6e 67 20 6d 65 73 73 61 67 65 00 00 00 00 00
00 00 00 41 64 64 65 64 20 6e 65 77 20 65 6e 74 72 79 20 <25> 64 20 66 6f
72 20 66 69 6c 65 20 63 61 63 68 65 2c 20 66 69 6c
RSP: 002b:00007ffccc2796a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000443b78
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004c34f0 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d5180 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor407:8173 blocked for more than 140 seconds.
Not tainted 4.19.40 #9
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor407 D27584 8173 8030 0x80000002
Call Trace:
context_switch kernel/sched/core.c:2826 [inline]
__schedule+0x813/0x1d00 kernel/sched/core.c:3474
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x933/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:979
__do_sys_exit_group kernel/exit.c:990 [inline]
__se_sys_exit_group kernel/exit.c:988 [inline]
__x64_sys_exit_group+0x44/0x50 kernel/exit.c:988
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443b78
Code: 64 69 73 63 61 72 64 69 6e 67 20 6d 65 73 73 61 67 65 00 00 00 00 00
00 00 00 41 64 64 65 64 20 6e 65 77 20 65 6e 74 72 79 20 <25> 64 20 66 6f
72 20 66 69 6c 65 20 63 61 63 68 65 2c 20 66 69 6c
RSP: 002b:00007ffccc2796a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000443b78
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004c34f0 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d5180 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor407:8309 blocked for more than 140 seconds.
Not tainted 4.19.40 #9
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor407 D28216 8309 8034 0x80000002
Call Trace:
context_switch kernel/sched/core.c:2826 [inline]
__schedule+0x813/0x1d00 kernel/sched/core.c:3474
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x933/0x2fa0 kernel/exit.c:876
do_group_exit+0x135/0x370 kernel/exit.c:979
__do_sys_exit_group kernel/exit.c:990 [inline]
__se_sys_exit_group kernel/exit.c:988 [inline]
__x64_sys_exit_group+0x44/0x50 kernel/exit.c:988
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443b78
Code: 64 69 73 63 61 72 64 69 6e 67 20 6d 65 73 73 61 67 65 00 00 00 00 00
00 00 00 41 64 64 65 64 20 6e 65 77 20 65 6e 74 72 79 20 <25> 64 20 66 6f
72 20 66 69 6c 65 20 63 61 63 68 65 2c 20 66 69 6c
RSP: 002b:00007ffccc2796a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000443b78
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004c34f0 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 000000000000000f R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d5180 R14: 0000000000000000 R15: 0000000000000000
Showing all locks held in the system:
2 locks held by ksoftirqd/0/9:
#0: 0000000017b51b5d (&rq->lock){-.-.}, at: rq_lock
kernel/sched/sched.h:1821 [inline]
#0: 0000000017b51b5d (&rq->lock){-.-.}, at: __schedule+0x1f8/0x1d00
kernel/sched/core.c:3412
#1: 0000000051461550 (rcu_read_lock){....}, at: trace_sched_stat_runtime
include/trace/events/sched.h:423 [inline]
#1: 0000000051461550 (rcu_read_lock){....}, at: update_curr+0x2ce/0x8a0
kernel/sched/fair.c:828
1 lock held by khungtaskd/1032:
#0: 0000000051461550 (rcu_read_lock){....}, at:
debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4435
1 lock held by rsyslogd/7880:
#0: 000000000ab628ce (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110
fs/file.c:767
2 locks held by getty/8002:
#0: 000000002b6e20aa (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
#1: 000000005d0ff065 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/8003:
#0: 000000007c11ae8e (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
#1: 000000007a5e92df (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/8004:
#0: 00000000c091c44e (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
#1: 00000000bd3bdd5f (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/8005:
#0: 00000000ef1e488c (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
#1: 00000000fc0d83d2 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/8006:
#0: 000000008f7de511 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
#1: 0000000084638674 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/8007:
#0: 00000000e51efc54 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
#1: 00000000ac9c6ab2 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/8008:
#0: 00000000064afc1b (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
#1: 0000000086c02416 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 1032 Comm: khungtaskd Not tainted 4.19.40 #9
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+0x357/0x430 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x2/0x10
arch/x86/include/asm/irqflags.h:57