INFO: task hung in fb_release
5 views
Skip to first unread message
syzbot
Dec 10, 2019, 3:20:11 AM12/10/19
to syzkaller...@googlegroups.com
Hello,
syzbot found the following crash on:
HEAD commit: a844dc4c Linux 4.14.158
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=164df446e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c02bef505ffc02ff
dashboard link: https://syzkaller.appspot.com/bug?extid=2e177b22e4c36407d8ee
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2e177b...@syzkaller.appspotmail.com
kobject: 'kvm' (ffff8880a6410dd0): fill_kobj_path: path
= '/devices/virtual/misc/kvm'
kobject: 'kvm' (ffff8880a6410dd0): kobject_uevent_env
kobject: 'kvm' (ffff8880a6410dd0): fill_kobj_path: path
= '/devices/virtual/misc/kvm'
INFO: task syz-executor.4:10326 blocked for more than 140 seconds.
Not tainted 4.14.158-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D28528 10326 7164 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
__fput+0x275/0x7a0 fs/file_table.c:210
____fput+0x16/0x20 fs/file_table.c:244
task_work_run+0x114/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414291
RSP: 002b:00007fffb1f94b80 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000414291
RDX: 0000000000000000 RSI: 000000000000182f RDI: 0000000000000006
RBP: 0000000000000001 R08: 00000000358b782f R09: 00000000358b7833
R10: 00007fffb1f94c60 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 0000000000762800 R15: 000000000075bfd4
INFO: task syz-executor.0:10327 blocked for more than 140 seconds.
Not tainted 4.14.158-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0 D28528 10327 7159 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
__fput+0x275/0x7a0 fs/file_table.c:210
____fput+0x16/0x20 fs/file_table.c:244
task_work_run+0x114/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414291
RSP: 002b:00007ffc16360270 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000414291
RDX: 0000000000000000 RSI: 000000000000182f RDI: 0000000000000004
RBP: 0000000000000001 R08: 00000000358b782f R09: 00000000358b7833
R10: 00007ffc16360350 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 0000000000761c08 R15: 000000000075bfd4
INFO: task syz-executor.2:10366 blocked for more than 140 seconds.
Not tainted 4.14.158-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2 D28416 10366 7162 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468
chrdev_open+0x207/0x590 fs/char_dev.c:423
do_dentry_open+0x73b/0xeb0 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:891
do_last fs/namei.c:3425 [inline]
path_openat+0x8bd/0x3f70 fs/namei.c:3566
do_filp_open+0x18e/0x250 fs/namei.c:3600
do_sys_open+0x2c5/0x430 fs/open.c:1084
SYSC_openat fs/open.c:1111 [inline]
SyS_openat+0x30/0x40 fs/open.c:1105
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a6f9
RSP: 002b:00007f45de4e5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a6f9
RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f45de4e66d4
R13: 00000000004c7e63 R14: 00000000004df000 R15: 00000000ffffffff
Showing all locks held in the system:
1 lock held by khungtaskd/1044:
#0: (tasklist_lock){.+.+}, at: [<ffffffff8148c8a8>]
debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
1 lock held by rsyslogd/6992:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffff81966a1b>]
__fdget_pos+0xab/0xd0 fs/file.c:769
2 locks held by getty/7114:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7115:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7116:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7117:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7118:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7119:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7120:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.4/10326:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83249375>]
fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
1 lock held by syz-executor.0/10327:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83249375>]
fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
1 lock held by syz-executor.2/10366:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83249cb7>] fb_open+0xb7/0x420
drivers/video/fbdev/core/fbmem.c:1468
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 1044 Comm: khungtaskd Not tainted 4.14.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x142/0x197 lib/dump_stack.c:58
nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x141/0x189 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:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
watchdog+0x5e7/0xb90 kernel/hung_task.c:274
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2204 Comm: kworker/u4:3 Not tainted 4.14.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
task: ffff8880a403a540 task.stack: ffff8880a4040000
RIP: 0010:__lock_release kernel/locking/lockdep.c:3772 [inline]
RIP: 0010:lock_release+0x2a8/0x940 kernel/locking/lockdep.c:4013
RSP: 0018:ffff8880a4047c48 EFLAGS: 00000806
RAX: dffffc0000000000 RBX: 1ffff11014808f8f RCX: ffff8880a403ae10
RDX: 1ffff110148075c6 RSI: 0000000000000000 RDI: ffff8880a403ae32
RBP: ffff8880a4047ce0 R08: ffff8880a403a540 R09: 0000000000000003
R10: 0000000000000000 R11: ffff8880a403a540 R12: ffffffff87f888a0
R13: ffffffff864c970d R14: ffffffff89a8bc80 R15: ffff8880a4047cb8
FS: 0000000000000000(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1cc0917000 CR3: 0000000072a95000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_lock_release include/linux/rcupdate.h:247 [inline]
rcu_read_unlock include/linux/rcupdate.h:685 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:420 [inline]
batadv_nc_worker+0x1d8/0x6d0 net/batman-adv/network-coding.c:726
process_one_work+0x863/0x1600 kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: d0 7c 08 84 d2 0f 85 57 05 00 00 8b 71 24 85 f6 0f 85 e0 55 00 00 48
8d 79 22 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02
48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot found the following crash on:
HEAD commit: a844dc4c Linux 4.14.158
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=164df446e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=c02bef505ffc02ff
dashboard link: https://syzkaller.appspot.com/bug?extid=2e177b22e4c36407d8ee
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2e177b...@syzkaller.appspotmail.com
kobject: 'kvm' (ffff8880a6410dd0): fill_kobj_path: path
= '/devices/virtual/misc/kvm'
kobject: 'kvm' (ffff8880a6410dd0): kobject_uevent_env
kobject: 'kvm' (ffff8880a6410dd0): fill_kobj_path: path
= '/devices/virtual/misc/kvm'
INFO: task syz-executor.4:10326 blocked for more than 140 seconds.
Not tainted 4.14.158-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D28528 10326 7164 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
__fput+0x275/0x7a0 fs/file_table.c:210
____fput+0x16/0x20 fs/file_table.c:244
task_work_run+0x114/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414291
RSP: 002b:00007fffb1f94b80 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000414291
RDX: 0000000000000000 RSI: 000000000000182f RDI: 0000000000000006
RBP: 0000000000000001 R08: 00000000358b782f R09: 00000000358b7833
R10: 00007fffb1f94c60 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 0000000000762800 R15: 000000000075bfd4
INFO: task syz-executor.0:10327 blocked for more than 140 seconds.
Not tainted 4.14.158-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0 D28528 10327 7159 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
__fput+0x275/0x7a0 fs/file_table.c:210
____fput+0x16/0x20 fs/file_table.c:244
task_work_run+0x114/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x414291
RSP: 002b:00007ffc16360270 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000414291
RDX: 0000000000000000 RSI: 000000000000182f RDI: 0000000000000004
RBP: 0000000000000001 R08: 00000000358b782f R09: 00000000358b7833
R10: 00007ffc16360350 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 0000000000761c08 R15: 000000000075bfd4
INFO: task syz-executor.2:10366 blocked for more than 140 seconds.
Not tainted 4.14.158-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2 D28416 10366 7162 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
fb_open+0xb7/0x420 drivers/video/fbdev/core/fbmem.c:1468
chrdev_open+0x207/0x590 fs/char_dev.c:423
do_dentry_open+0x73b/0xeb0 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:891
do_last fs/namei.c:3425 [inline]
path_openat+0x8bd/0x3f70 fs/namei.c:3566
do_filp_open+0x18e/0x250 fs/namei.c:3600
do_sys_open+0x2c5/0x430 fs/open.c:1084
SYSC_openat fs/open.c:1111 [inline]
SyS_openat+0x30/0x40 fs/open.c:1105
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a6f9
RSP: 002b:00007f45de4e5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a6f9
RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f45de4e66d4
R13: 00000000004c7e63 R14: 00000000004df000 R15: 00000000ffffffff
Showing all locks held in the system:
1 lock held by khungtaskd/1044:
#0: (tasklist_lock){.+.+}, at: [<ffffffff8148c8a8>]
debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
1 lock held by rsyslogd/6992:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffff81966a1b>]
__fdget_pos+0xab/0xd0 fs/file.c:769
2 locks held by getty/7114:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7115:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7116:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7117:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7118:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7119:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/7120:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866549c3>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff83490d76>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.4/10326:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83249375>]
fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
1 lock held by syz-executor.0/10327:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83249375>]
fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1497
1 lock held by syz-executor.2/10366:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83249cb7>] fb_open+0xb7/0x420
drivers/video/fbdev/core/fbmem.c:1468
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 1044 Comm: khungtaskd Not tainted 4.14.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x142/0x197 lib/dump_stack.c:58
nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x141/0x189 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:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
watchdog+0x5e7/0xb90 kernel/hung_task.c:274
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2204 Comm: kworker/u4:3 Not tainted 4.14.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
task: ffff8880a403a540 task.stack: ffff8880a4040000
RIP: 0010:__lock_release kernel/locking/lockdep.c:3772 [inline]
RIP: 0010:lock_release+0x2a8/0x940 kernel/locking/lockdep.c:4013
RSP: 0018:ffff8880a4047c48 EFLAGS: 00000806
RAX: dffffc0000000000 RBX: 1ffff11014808f8f RCX: ffff8880a403ae10
RDX: 1ffff110148075c6 RSI: 0000000000000000 RDI: ffff8880a403ae32
RBP: ffff8880a4047ce0 R08: ffff8880a403a540 R09: 0000000000000003
R10: 0000000000000000 R11: ffff8880a403a540 R12: ffffffff87f888a0
R13: ffffffff864c970d R14: ffffffff89a8bc80 R15: ffff8880a4047cb8
FS: 0000000000000000(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1cc0917000 CR3: 0000000072a95000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_lock_release include/linux/rcupdate.h:247 [inline]
rcu_read_unlock include/linux/rcupdate.h:685 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:420 [inline]
batadv_nc_worker+0x1d8/0x6d0 net/batman-adv/network-coding.c:726
process_one_work+0x863/0x1600 kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: d0 7c 08 84 d2 0f 85 57 05 00 00 8b 71 24 85 f6 0f 85 e0 55 00 00 48
8d 79 22 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02
48 89 f8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot
Apr 8, 2020, 12:15:12 AM4/8/20
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following crash on:
HEAD commit: 4520f06b Linux 4.14.175
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=115fda9fe00000
kernel config: https://syzkaller.appspot.com/x/.config?x=93cf891381c0c347
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=136dc11be00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2e177b...@syzkaller.appspotmail.com
INFO: task syz-executor088:6349 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
__fput+0x25f/0x790 fs/file_table.c:210
task_work_run+0x113/0x190 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x9f2/0x2b00 kernel/exit.c:858
do_group_exit+0x100/0x310 kernel/exit.c:955
get_signal+0x385/0x1ca0 kernel/signal.c:2423
do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000441419
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor088:6360 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
chrdev_open+0x1fc/0x540 fs/char_dev.c:423
do_dentry_open+0x732/0xe90 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:888
do_last fs/namei.c:3428 [inline]
path_openat+0x8ca/0x3c50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x29d/0x3f0 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor088:6361 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
chrdev_open+0x1fc/0x540 fs/char_dev.c:423
do_dentry_open+0x732/0xe90 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:888
do_last fs/namei.c:3428 [inline]
path_openat+0x8ca/0x3c50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x29d/0x3f0 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor088:6362 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
chrdev_open+0x1fc/0x540 fs/char_dev.c:423
do_dentry_open+0x732/0xe90 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:888
do_last fs/namei.c:3428 [inline]
path_openat+0x8ca/0x3c50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x29d/0x3f0 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor088:6363 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
chrdev_open+0x1fc/0x540 fs/char_dev.c:423
do_dentry_open+0x732/0xe90 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:888
do_last fs/namei.c:3428 [inline]
path_openat+0x8ca/0x3c50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x29d/0x3f0 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
Showing all locks held in the system:
1 lock held by khungtaskd/1056:
#0: (tasklist_lock){.+.+}, at: [<ffffffff81465bb3>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544
1 lock held by in:imklog/6049:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffff8191b836>] __fdget_pos+0xa6/0xc0 fs/file.c:769
1 lock held by syz-executor088/6349:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff831715be>] fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1497
1 lock held by syz-executor088/6360:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83171ec7>] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
1 lock held by syz-executor088/6361:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83171ec7>] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
1 lock held by syz-executor088/6362:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83171ec7>] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
1 lock held by syz-executor088/6363:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83171ec7>] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 1056 Comm: khungtaskd Not tainted 4.14.175-syzkaller #0
nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x139/0x17e lib/nmi_backtrace.c:62
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
RIP: 0010:bitfill_aligned+0x22/0x190 drivers/video/fbdev/core/cfbfillrect.c:40
RSP: 0018:ffff888097bff318 EFLAGS: 00000297
RAX: ffff888098342300 RBX: ffff8880000a0000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880000a0000 RDI: ffff8882192b2e40
RBP: 0000000000001400 R08: 0000000000001400 R09: 0000000000000040
R10: ffffed104323b873 R11: ffff8882191dc39f R12: 0000000000000040
R13: 0000000061b8135f R14: 0000000000000000 R15: 0000000000000000
FS: 00000000007fc880(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
vga16fb_fillrect+0x61e/0x1880 drivers/video/fbdev/vga16fb.c:951
bit_clear_margins+0x2a4/0x480 drivers/video/fbdev/core/bitblit.c:232
fbcon_clear_margins+0x285/0x310 drivers/video/fbdev/core/fbcon.c:1317
fbcon_switch+0xcdf/0x1780 drivers/video/fbdev/core/fbcon.c:2299
redraw_screen+0x331/0x770 drivers/tty/vt/vt.c:689
fbcon_modechanged+0x59d/0x890 drivers/video/fbdev/core/fbcon.c:2946
fbcon_event_notify+0x11a/0x1746 drivers/video/fbdev/core/fbcon.c:3299
notifier_call_chain+0x107/0x1a0 kernel/notifier.c:93
__blocking_notifier_call_chain kernel/notifier.c:317 [inline]
__blocking_notifier_call_chain kernel/notifier.c:304 [inline]
blocking_notifier_call_chain kernel/notifier.c:328 [inline]
blocking_notifier_call_chain+0x79/0x90 kernel/notifier.c:325
fb_set_var+0xaad/0xc70 drivers/video/fbdev/core/fbmem.c:1054
do_fb_ioctl+0x3cc/0x940 drivers/video/fbdev/core/fbmem.c:1127
fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1242
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 000000000010150f R08: 00000009004002c8 R09: 00000009004002c8
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
Code: ff 0f 1f 84 00 00 00 00 00 41 57 49 89 cf 41 56 41 89 d6 41 55 41 54 45 89 cc 55 44 89 c5 53 48 89 f3 48 83 ec 08 e8 5e 41 3f fe <85> ed 74 5f e8 55 41 3f fe 41 8d 3c 2e 44 89 f1 31 d2 49 c7 c5
HEAD commit: 4520f06b Linux 4.14.175
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=115fda9fe00000
kernel config: https://syzkaller.appspot.com/x/.config?x=93cf891381c0c347
dashboard link: https://syzkaller.appspot.com/bug?extid=2e177b22e4c36407d8ee
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fdfd8fe00000
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=136dc11be00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2e177b...@syzkaller.appspotmail.com
Not tainted 4.14.175-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor088 D27520 6349 6347 0x80000006
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1497
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
__fput+0x25f/0x790 fs/file_table.c:210
task_work_run+0x113/0x190 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x9f2/0x2b00 kernel/exit.c:858
do_group_exit+0x100/0x310 kernel/exit.c:955
get_signal+0x385/0x1ca0 kernel/signal.c:2423
do_signal+0x7c/0x1690 arch/x86/kernel/signal.c:814
exit_to_usermode_loop+0x159/0x220 arch/x86/entry/common.c:160
prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000441419
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 00000000006cb018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor088:6360 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor088 D28688 6360 6348 0x00000004
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
chrdev_open+0x1fc/0x540 fs/char_dev.c:423
do_dentry_open+0x732/0xe90 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:888
do_last fs/namei.c:3428 [inline]
path_openat+0x8ca/0x3c50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x29d/0x3f0 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c
RBP: 0000000000101510 R08: 0000000000000004 R09: 00000009004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor088:6361 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor088 D28688 6361 6352 0x00000004
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
chrdev_open+0x1fc/0x540 fs/char_dev.c:423
do_dentry_open+0x732/0xe90 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:888
do_last fs/namei.c:3428 [inline]
path_openat+0x8ca/0x3c50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x29d/0x3f0 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c
RBP: 0000000000101512 R08: 0000000000000004 R09: 00000009004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor088:6362 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor088 D28688 6362 6350 0x00000004
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
chrdev_open+0x1fc/0x540 fs/char_dev.c:423
do_dentry_open+0x732/0xe90 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:888
do_last fs/namei.c:3428 [inline]
path_openat+0x8ca/0x3c50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x29d/0x3f0 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c
RBP: 0000000000101515 R08: 0000000000000004 R09: 00000009004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor088:6363 blocked for more than 140 seconds.
Not tainted 4.14.175-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor088 D28688 6363 6351 0x00000004
Call Trace:
schedule+0x8d/0x1b0 kernel/sched/core.c:3428
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
chrdev_open+0x1fc/0x540 fs/char_dev.c:423
do_dentry_open+0x732/0xe90 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:888
do_last fs/namei.c:3428 [inline]
path_openat+0x8ca/0x3c50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x29d/0x3f0 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c
RBP: 000000000010150f R08: 0000000000000004 R09: 00000009004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
Showing all locks held in the system:
#0: (tasklist_lock){.+.+}, at: [<ffffffff81465bb3>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544
1 lock held by in:imklog/6049:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffff8191b836>] __fdget_pos+0xa6/0xc0 fs/file.c:769
1 lock held by syz-executor088/6349:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff831715be>] fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1497
1 lock held by syz-executor088/6360:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83171ec7>] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
1 lock held by syz-executor088/6361:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83171ec7>] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
1 lock held by syz-executor088/6362:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83171ec7>] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
1 lock held by syz-executor088/6363:
#0: (&fb_info->lock){+.+.}, at: [<ffffffff83171ec7>] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 1056 Comm: khungtaskd Not tainted 4.14.175-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x13e/0x194 lib/dump_stack.c:58
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x139/0x17e lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
watchdog+0x5e2/0xb80 kernel/hung_task.c:274
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
kthread+0x30d/0x420 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6359 Comm: syz-executor088 Not tainted 4.14.175-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888098342300 task.stack: ffff888097bf8000
RIP: 0010:bitfill_aligned+0x22/0x190 drivers/video/fbdev/core/cfbfillrect.c:40
RSP: 0018:ffff888097bff318 EFLAGS: 00000297
RAX: ffff888098342300 RBX: ffff8880000a0000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880000a0000 RDI: ffff8882192b2e40
RBP: 0000000000001400 R08: 0000000000001400 R09: 0000000000000040
R10: ffffed104323b873 R11: ffff8882191dc39f R12: 0000000000000040
R13: 0000000061b8135f R14: 0000000000000000 R15: 0000000000000000
FS: 00000000007fc880(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 00000000a546a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
cfb_fillrect+0x3d5/0x720 drivers/video/fbdev/core/cfbfillrect.c:327
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vga16fb_fillrect+0x61e/0x1880 drivers/video/fbdev/vga16fb.c:951
bit_clear_margins+0x2a4/0x480 drivers/video/fbdev/core/bitblit.c:232
fbcon_clear_margins+0x285/0x310 drivers/video/fbdev/core/fbcon.c:1317
fbcon_switch+0xcdf/0x1780 drivers/video/fbdev/core/fbcon.c:2299
redraw_screen+0x331/0x770 drivers/tty/vt/vt.c:689
fbcon_modechanged+0x59d/0x890 drivers/video/fbdev/core/fbcon.c:2946
fbcon_event_notify+0x11a/0x1746 drivers/video/fbdev/core/fbcon.c:3299
notifier_call_chain+0x107/0x1a0 kernel/notifier.c:93
__blocking_notifier_call_chain kernel/notifier.c:317 [inline]
__blocking_notifier_call_chain kernel/notifier.c:304 [inline]
blocking_notifier_call_chain kernel/notifier.c:328 [inline]
blocking_notifier_call_chain+0x79/0x90 kernel/notifier.c:325
fb_set_var+0xaad/0xc70 drivers/video/fbdev/core/fbmem.c:1054
do_fb_ioctl+0x3cc/0x940 drivers/video/fbdev/core/fbmem.c:1127
fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1242
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441419
RSP: 002b:00007ffcf9fa5f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441419
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 000000000010150f R08: 00000009004002c8 R09: 00000009004002c8
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000402190
R13: 0000000000402220 R14: 0000000000000000 R15: 0000000000000000
Code: ff 0f 1f 84 00 00 00 00 00 41 57 49 89 cf 41 56 41 89 d6 41 55 41 54 45 89 cc 55 44 89 c5 53 48 89 f3 48 83 ec 08 e8 5e 41 3f fe <85> ed 74 5f e8 55 41 3f fe 41 8d 3c 2e 44 89 f1 31 d2 49 c7 c5
syzbot
Aug 27, 2020, 8:53:06 AM8/27/20
to syzkaller...@googlegroups.com
syzbot suspects this issue was fixed by commit:
commit c388072f90cc2d5884cf42e0c6d605d65d323b41
Author: Tetsuo Handa <penguin...@I-love.SAKURA.ne.jp>
Date: Wed Jul 15 01:51:02 2020 +0000
fbdev: Detect integer underflow at "struct fbcon_ops"->clear_margins.
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12367661900000
start commit: 4520f06b Linux 4.14.175
git tree: linux-4.14.y
#syz fix: fbdev: Detect integer underflow at "struct fbcon_ops"->clear_margins.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
commit c388072f90cc2d5884cf42e0c6d605d65d323b41
Author: Tetsuo Handa <penguin...@I-love.SAKURA.ne.jp>
Date: Wed Jul 15 01:51:02 2020 +0000
fbdev: Detect integer underflow at "struct fbcon_ops"->clear_margins.
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12367661900000
start commit: 4520f06b Linux 4.14.175
git tree: linux-4.14.y
kernel config: https://syzkaller.appspot.com/x/.config?x=93cf891381c0c347
dashboard link: https://syzkaller.appspot.com/bug?extid=2e177b22e4c36407d8ee
dashboard link: https://syzkaller.appspot.com/bug?extid=2e177b22e4c36407d8ee
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fdfd8fe00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=136dc11be00000
If the result looks correct, please mark the issue as fixed by replying with:
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=136dc11be00000
#syz fix: fbdev: Detect integer underflow at "struct fbcon_ops"->clear_margins.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
Reply all
Reply to author
Forward
0 new messages