INFO: task hung in console_device

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 47bbcd6b ANDROID: Fix massive cpufreq_times memory leaks
git tree: android-4.9
console output: https://syzkaller.appspot.com/x/log.txt?x=131f0768400000
kernel config: https://syzkaller.appspot.com/x/.config?x=f2dbd0c9dd968786
dashboard link: https://syzkaller.appspot.com/bug?extid=40cf3cb694024c867daf
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13fda978400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d1c658400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+40cf3c...@syzkaller.appspotmail.com

binder: 13899:13899 transaction failed 29189/-22, size 24-8 line 3013
binder: 13900:13900 transaction failed 29189/-22, size 24-8 line 3013
binder: 13901:13901 transaction failed 29189/-22, size 24-8 line 3013
binder: 13902:13902 transaction failed 29189/-22, size 24-8 line 3013
binder: 13903:13903 transaction failed 29189/-22, size 24-8 line 3013
INFO: task init:5690 blocked for more than 140 seconds.
Not tainted 4.9.113-g47bbcd6 #10
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
init D27736 5690 1 0x00000000
ffff8801cc7d1800 0000000000000000 ffff8801cc6e64c0 ffff8801d9a39800
ffff8801db221c18 ffff8801ccb17570 ffffffff839e909d 0000000000000000
ffff8801cc7d20ea ffff8801ccb176d0 0000000000000046 ffff8801db2224e8
Call Trace:
[<ffffffff839ea69f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
[<ffffffff839f6ab1>] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768
[<ffffffff839f31ce>] __down_common kernel/locking/semaphore.c:221 [inline]
[<ffffffff839f31ce>] __down+0x12e/0x1f0 kernel/locking/semaphore.c:238
[<ffffffff8122bd4e>] down+0x5e/0x80 kernel/locking/semaphore.c:61
[<ffffffff8125a62c>] console_lock+0x2c/0x80 kernel/printk/printk.c:2212
[<ffffffff8125fe9c>] console_device+0x1c/0xc0 kernel/printk/printk.c:2549
[<ffffffff821194da>] tty_lookup_driver drivers/tty/tty_io.c:2003 [inline]
[<ffffffff821194da>] tty_open_by_driver drivers/tty/tty_io.c:2048 [inline]
[<ffffffff821194da>] tty_open+0x71a/0xe20 drivers/tty/tty_io.c:2125
[<ffffffff8157ee6d>] chrdev_open+0x22d/0x4c0 fs/char_dev.c:392
[<ffffffff81569d53>] do_dentry_open+0x703/0xc80 fs/open.c:766
[<ffffffff8156d53c>] vfs_open+0x11c/0x210 fs/open.c:879
[<ffffffff815a4678>] do_last fs/namei.c:3410 [inline]
[<ffffffff815a4678>] path_openat+0x758/0x3590 fs/namei.c:3534
[<ffffffff815ab777>] do_filp_open+0x197/0x270 fs/namei.c:3568
[<ffffffff8156df4d>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
[<ffffffff8156e22d>] SYSC_open fs/open.c:1090 [inline]
[<ffffffff8156e22d>] SyS_open+0x2d/0x40 fs/open.c:1085
[<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
[<ffffffff839f9f93>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/519:
#0: (rcu_read_lock){......}, at: [<ffffffff8136675c>]
check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
#0: (rcu_read_lock){......}, at: [<ffffffff8136675c>]
watchdog+0x11c/0xa20 kernel/hung_task.c:239
#1: (tasklist_lock){.+.+..}, at: [<ffffffff81425de7>]
debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3673:
#0: (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d81ec>]
__fdget_pos+0xac/0xd0 fs/file.c:781
2 locks held by getty/3769:
#0: (&tty->ldisc_sem){++++++}, at: [<ffffffff839f8142>]
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
#1: (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff8211ee22>]
n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by init/5690:
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open_by_driver
drivers/tty/tty_io.c:2047 [inline]
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open+0x46c/0xe20
drivers/tty/tty_io.c:2125
1 lock held by init/5693:
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open_by_driver
drivers/tty/tty_io.c:2047 [inline]
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open+0x46c/0xe20
drivers/tty/tty_io.c:2125
1 lock held by init/5696:
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open_by_driver
drivers/tty/tty_io.c:2047 [inline]
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open+0x46c/0xe20
drivers/tty/tty_io.c:2125
1 lock held by init/5697:
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open_by_driver
drivers/tty/tty_io.c:2047 [inline]
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open+0x46c/0xe20
drivers/tty/tty_io.c:2125
1 lock held by init/5700:
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open_by_driver
drivers/tty/tty_io.c:2047 [inline]
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open+0x46c/0xe20
drivers/tty/tty_io.c:2125
1 lock held by init/5701:
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open_by_driver
drivers/tty/tty_io.c:2047 [inline]
#0: (tty_mutex){+.+.+.}, at: [<ffffffff8211922c>] tty_open+0x46c/0xe20
drivers/tty/tty_io.c:2125

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.113-g47bbcd6 #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
ffff8801d864fd08 ffffffff81eb32a9 0000000000000000 0000000000000001
0000000000000001
binder: 13904:13904 transaction failed 29189/-22, size 24-8 line 3013
0000000000000001 ffffffff810b9bd0 ffff8801d864fd40
Call Trace:
[<ffffffff81eb32a9>] __dump_stack lib/dump_stack.c:15 [inline]
[<ffffffff81eb32a9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
[<ffffffff81ebe5a7>] nmi_cpu_backtrace.cold.2+0x48/0x87
lib/nmi_backtrace.c:99
[<ffffffff81ebe53a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f
lib/nmi_backtrace.c:60
[<ffffffff810b9cd4>] arch_trigger_cpumask_backtrace+0x14/0x20
arch/x86/kernel/apic/hw_nmi.c:37
[<ffffffff81366cf4>] trigger_all_cpu_backtrace include/linux/nmi.h:58
[inline]
[<ffffffff81366cf4>] check_hung_task kernel/hung_task.c:125 [inline]
[<ffffffff81366cf4>] check_hung_uninterruptible_tasks
kernel/hung_task.c:182 [inline]
[<ffffffff81366cf4>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
[<ffffffff8119d0ad>] kthread+0x26d/0x300 kernel/kthread.c:211
[<ffffffff839fa15c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 13904 Comm: syz-executor192 Not tainted 4.9.113-g47bbcd6 #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
task: ffff880198406000 task.stack: ffff88018e0f8000
RIP: 0010:[<ffffffff81236bcf>] c [<ffffffff81236bcf>]
__lock_acquire+0xa1f/0x4070 kernel/locking/lockdep.c:3224
RSP: 0018:ffff88018e0ff430 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 1ffffffff0b7bc8c RSI: 0000000000000000 RDI: ffffffff85bde460
RBP: ffff88018e0ff5d8 R08: 0000000000000001 R09: 0000000000000001
R10: ffff880198406000 R11: 0000000000000001 R12: 0000000000000001
R13: 0000000000000000 R14: ffffffff85bde460 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006d1090 CR3: 000000000461e000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
ffffffff812361b0 c ffff88018e0ff460 c ffffffff8122bcd0 c 0000000000000006 c
ffffffff855891b0 c ffffffff8125f493 c 0000000000000ff8 c ffff8801984068e0 c
ffff8801984068b8 c ffff8801984068e8 c ffffffff855891b0 c ffff8801984068c8 c
Call Trace:
[<ffffffff8123ac90>] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
[<ffffffff839f9ebe>] __raw_spin_lock_irqsave
include/linux/spinlock_api_smp.h:112 [inline]
[<ffffffff839f9ebe>] _raw_spin_lock_irqsave+0x4e/0x62
kernel/locking/spinlock.c:159
[<ffffffff81f1dd74>] __debug_check_no_obj_freed lib/debugobjects.c:711
[inline]
[<ffffffff81f1dd74>] debug_check_no_obj_freed+0x164/0x930
lib/debugobjects.c:749
[<ffffffff8144a49d>] free_pages_prepare mm/page_alloc.c:1073 [inline]
[<ffffffff8144a49d>] __free_pages_ok+0x1dd/0x1610 mm/page_alloc.c:1275
[<ffffffff8144b92e>] free_compound_page+0x5e/0x70 mm/page_alloc.c:606
[<ffffffff81551ce9>] free_transhuge_page+0x99/0xc0 mm/huge_memory.c:2229
[<ffffffff81463d30>] __put_compound_page+0x80/0xc0 mm/swap.c:94
[<ffffffff81465924>] release_pages+0x2f4/0x970 mm/swap.c:763
[<ffffffff81508b47>] free_pages_and_swap_cache+0x117/0x160
mm/swap_state.c:273
[<ffffffff814c00d4>] tlb_flush_mmu_free+0xb4/0x150 mm/memory.c:259
[<ffffffff814c850d>] zap_pte_range mm/memory.c:1216 [inline]
[<ffffffff814c850d>] zap_pmd_range mm/memory.c:1258 [inline]
[<ffffffff814c850d>] zap_pud_range mm/memory.c:1279 [inline]
[<ffffffff814c850d>] unmap_page_range+0x104d/0x1730 mm/memory.c:1300
[<ffffffff814c8cf1>] unmap_single_vma+0x101/0x260 mm/memory.c:1345
[<ffffffff814c9632>] unmap_vmas+0x102/0x1d0 mm/memory.c:1375
[<ffffffff814e1d94>] exit_mmap+0x214/0x3f0 mm/mmap.c:3020
[<ffffffff8112bff3>] __mmput kernel/fork.c:881 [inline]
[<ffffffff8112bff3>] mmput+0xf3/0x2d0 kernel/fork.c:903
[<ffffffff81140de6>] exit_mm kernel/exit.c:514 [inline]
[<ffffffff81140de6>] do_exit+0x906/0x27b0 kernel/exit.c:820
[<ffffffff81146fa1>] do_group_exit+0x111/0x340 kernel/exit.c:937
[<ffffffff811471ed>] SYSC_exit_group kernel/exit.c:948 [inline]
[<ffffffff811471ed>] SyS_exit_group+0x1d/0x20 kernel/exit.c:946
[<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
[<ffffffff839f9f93>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: c00 c0f c85 c17 c27 c00 c00 c48 c8d c65 cd8 c5b c41 c5c
c41 c5d c41 c5e c41 c5f c5d cc3 c48 cb8 c00 c00 c00 c00 c00
cfc cff cdf c4c c89 cf2 c48 cc1 cea c03 c80 c3c c02 c00
c<0f> c85 c51 c27 c00 c00 c49 c81 c3e ca0 c8c ce9 c84 c0f
c84 c08 cf7 cff cff c83 cfe c


---
This bug is generated by a bot. It may contain errors.
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[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b859aa7d ANDROID: squashfs: resolve merge conflict with 4...
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=11a0218e400000
kernel config: https://syzkaller.appspot.com/x/.config?x=c0bdd1b757a6ba0b
dashboard link: https://syzkaller.appspot.com/bug?extid=1b490365069fba8a3bbb

compiler: gcc (GCC) 8.0.1 20180413 (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+1b4903...@syzkaller.appspotmail.com

audit: type=1400 audit(1536420552.679:29198): avc: denied { map } for
pid=15638 comm="blkid" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1"
ino=2784 scontext=system_u:system_r:kernel_t:s0
tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
audit: type=1400 audit(1536420552.699:29199): avc: denied { map } for
pid=15638 comm="blkid" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1"
ino=2784 scontext=system_u:system_r:kernel_t:s0
tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
audit: type=1400 audit(1536420552.699:29200): avc: denied { map } for
pid=15638 comm="blkid" path="/lib/x86_64-linux-gnu/libuuid.so.1.3.0"
dev="sda1" ino=2819 scontext=system_u:system_r:kernel_t:s0
tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
INFO: task init:1 blocked for more than 140 seconds.
Not tainted 4.14.68+ #4

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

init D24664 1 0 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_timeout+0x710/0xe60 kernel/time/timer.c:1718
__down_common kernel/locking/semaphore.c:221 [inline]
__down+0x180/0x2a0 kernel/locking/semaphore.c:238
down+0x58/0x70 kernel/locking/semaphore.c:62
console_lock+0x24/0x70 kernel/printk/printk.c:2056
console_device+0x17/0xb0 kernel/printk/printk.c:2343
tty_lookup_driver+0x17a/0x210 drivers/tty/tty_io.c:1828
tty_open_by_driver drivers/tty/tty_io.c:1923 [inline]
tty_open+0x3b9/0x980 drivers/tty/tty_io.c:2006
chrdev_open+0x20d/0x570 fs/char_dev.c:417
do_dentry_open+0x426/0xda0 fs/open.c:764
vfs_open+0x11c/0x210 fs/open.c:878
do_last fs/namei.c:3408 [inline]
path_openat+0x4eb/0x23a0 fs/namei.c:3550
do_filp_open+0x197/0x270 fs/namei.c:3584
do_sys_open+0x2ef/0x580 fs/open.c:1071
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fe84da63120
RSP: 002b:00007fff3f56a448 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fe84da63120
RDX: 0000000000000000 RSI: 0000000000000901 RDI: 00000000004072c8
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000901
R13: 0000000000000901 R14: 0000000000000032 R15: 0000000001566358
INFO: task kworker/0:0:3 blocked for more than 140 seconds.
Not tainted 4.14.68+ #4

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

kworker/0:0 D27392 3 2 0x80000000
Workqueue: ipv6_addrconf addrconf_verify_work
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4432
process_one_work+0x86e/0x15c0 kernel/workqueue.c:2114
worker_thread+0xdc/0x1000 kernel/workqueue.c:2248
kthread+0x348/0x420 kernel/kthread.c:232
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402
INFO: task syz-executor6:15619 blocked for more than 140 seconds.
Not tainted 4.14.68+ #4

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

syz-executor6 D28536 15619 12525 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
raw_close+0xe/0x30 net/ipv4/raw.c:699
inet_release+0xf7/0x1c0 net/ipv4/af_inet.c:444
__sock_release+0xce/0x250 net/socket.c:602
sock_close+0x15/0x20 net/socket.c:1138
__fput+0x25e/0x6f0 fs/file_table.c:210
task_work_run+0x116/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x12e/0x150 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
do_syscall_64+0x35d/0x4b0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x410c51
RSP: 002b:00007ffc1e1bd380 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000410c51
RDX: 0000000020000000 RSI: 00000000007301e8 RDI: 0000000000000003
RBP: 0000000000000000 R08: ffffffffffffffff R09: ffffffffffffffff
R10: 00007ffc1e1bd2b0 R11: 0000000000000293 R12: 0000000000000000
R13: 00000000002f6cf5 R14: 000000000000010c R15: badc0ffeebadface

Showing all locks held in the system:

1 lock held by init/1:
#0: (tty_mutex){+.+.}, at: [<ffffffffa030c378>] tty_open_by_driver
drivers/tty/tty_io.c:1922 [inline]
#0: (tty_mutex){+.+.}, at: [<ffffffffa030c378>] tty_open+0x3a8/0x980
drivers/tty/tty_io.c:2006
3 locks held by kworker/0:0/3:
#0: ("%s"("ipv6_addrconf")){+.+.}, at: [<ffffffff9f727237>]
process_one_work+0x787/0x15c0 kernel/workqueue.c:2085
#1: ((addr_chk_work).work){+.+.}, at: [<ffffffff9f72726f>]
process_one_work+0x7bf/0x15c0 kernel/workqueue.c:2089
#2: (rtnl_mutex){+.+.}, at: [<ffffffffa0cba8ea>]
addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4432
1 lock held by khungtaskd/23:
#0: (tasklist_lock){.+.+}, at: [<ffffffff9f8019d7>]
debug_show_all_locks+0x74/0x20f kernel/locking/lockdep.c:4541
1 lock held by rsyslogd/1626:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffff9fbbcd02>]
__fdget_pos+0xa2/0xc0 fs/file.c:768
2 locks held by getty/1754:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffffa031c980>]
tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffffa0317eff>]
n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142
4 locks held by kworker/u4:0/14235:
#0: ("%s""netns"){+.+.}, at: [<ffffffff9f727237>]
process_one_work+0x787/0x15c0 kernel/workqueue.c:2085
#1: (net_cleanup_work){+.+.}, at: [<ffffffff9f72726f>]
process_one_work+0x7bf/0x15c0 kernel/workqueue.c:2089
#2: (net_mutex){+.+.}, at: [<ffffffffa08d2b1c>] cleanup_net+0x14c/0x880
net/core/net_namespace.c:449
#3: (rtnl_mutex){+.+.}, at: [<ffffffffa08d2b21>] cleanup_net+0x151/0x880
net/core/net_namespace.c:452
2 locks held by syz-executor6/15619:
#0: (&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffffa08818b4>]
inode_lock include/linux/fs.h:713 [inline]
#0: (&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffffa08818b4>]
__sock_release+0x84/0x250 net/socket.c:601
#1: (rtnl_mutex){+.+.}, at: [<ffffffffa0b4e4be>] raw_close+0xe/0x30
net/ipv4/raw.c:699

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

NMI backtrace for cpu 1

CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.68+ #4
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0xb9/0x11b lib/dump_stack.c:53
nmi_cpu_backtrace.cold.0+0x47/0x85 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x121/0x146 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline]
watchdog+0x574/0xa70 kernel/hung_task.c:252
kthread+0x348/0x420 kernel/kthread.c:232
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402

Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0

CPU: 0 PID: 10818 Comm: syz-executor5 Not tainted 4.14.68+ #4
task: ffff8801c9d8c680 task.stack: ffff8801c7c88000
RIP: 0033:0x4023c7
RSP: 002b:00007fa8c7567690 EFLAGS: 00000286
RAX: 000000009e9102a3 RBX: 0000000000000007 RCX: 0000000000457099
RDX: 0000000000000000 RSI: 00007fa8c75676c0 RDI: 0000000000000007
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d7008 R14: 00000000004ca112 R15: 0000000000000000
FS: 00007fa8c7568700(0000) GS:ffff8801dba00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007ffef5372608 CR3: 00000001c91c4004 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: d0c3914f UPSTREAM: dm: do not allow readahead to limit IO ..
git tree: android-4.4
console output: https://syzkaller.appspot.com/x/log.txt?x=12671ff7400000
kernel config: https://syzkaller.appspot.com/x/.config?x=e76b3f849c857277
dashboard link: https://syzkaller.appspot.com/bug?extid=902b5487179e8ddc6593
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14867b7f400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1216afcf400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:

Reported-by: syzbot+902b54...@syzkaller.appspotmail.com

binder: 28897:28909 ioctl 40046207 0 returned -16
binder: BINDER_SET_CONTEXT_MGR already set
binder: 28905:28910 ioctl 40046207 0 returned -16
binder: BINDER_SET_CONTEXT_MGR already set
binder: 28903:28913 ioctl 40046207 0 returned -16
INFO: task init:8553 blocked for more than 140 seconds.
Not tainted 4.4.171+ #12

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

init D ffff8800b52175b0 28912 8553 1 0x00000000
ffff8800b52175b0 ffff8801d3c5d008 0000000000000001 0000000000000000
ffff8800b52176d8 0000000000000000 ffff8801db71f180 ffff8801db71f1a8
ffff8801db71e898 ffff8801d3c5df00 ffff8801d3c5c740 ffffed0016a42001
Call Trace:
[<ffffffff82709249>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
[<ffffffff8271531b>] schedule_timeout+0x47b/0x7c0 kernel/time/timer.c:1515
[<ffffffff82712349>] __down_common kernel/locking/semaphore.c:221 [inline]
[<ffffffff82712349>] __down+0x189/0x2a0 kernel/locking/semaphore.c:238
[<ffffffff811f4c74>] down+0x64/0x90 kernel/locking/semaphore.c:61
[<ffffffff8121b58c>] console_lock+0x2c/0x80 kernel/printk/printk.c:2164
[<ffffffff81220c5c>] console_device+0x1c/0xc0 kernel/printk/printk.c:2435
[<ffffffff81c8b177>] tty_lookup_driver drivers/tty/tty_io.c:2000 [inline]
[<ffffffff81c8b177>] tty_open+0x8e7/0xf50 drivers/tty/tty_io.c:2068
[<ffffffff814a3aa0>] chrdev_open+0x230/0x630 fs/char_dev.c:388
[<ffffffff814912af>] do_dentry_open+0x38f/0xbd0 fs/open.c:749
[<ffffffff81494a9b>] vfs_open+0x10b/0x210 fs/open.c:862
[<ffffffff814c59bf>] do_last fs/namei.c:3269 [inline]
[<ffffffff814c59bf>] path_openat+0x136f/0x4470 fs/namei.c:3406
[<ffffffff814cc691>] do_filp_open+0x1a1/0x270 fs/namei.c:3440
[<ffffffff814953c8>] do_sys_open+0x2f8/0x600 fs/open.c:1038
[<ffffffff814956fd>] SYSC_open fs/open.c:1056 [inline]
[<ffffffff814956fd>] SyS_open+0x2d/0x40 fs/open.c:1051
[<ffffffff82717fe1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
1 lock held by init/8553:
#0: (tty_mutex){+.+.+.}, at: [<ffffffff81c8adfa>] tty_open+0x56a/0xf50
drivers/tty/tty_io.c:2067
Sending NMI to all CPUs:

NMI backtrace for cpu 0

CPU: 0 PID: 2254 Comm: syz-executor674 Not tainted 4.4.171+ #12
task: ffff8801d1f4af80 task.stack: ffff8801d0c58000
RIP: 0010:[<ffffffff81ad89b8>] [<ffffffff81ad89b8>] delay_tsc+0x38/0xc0
arch/x86/lib/delay.c:67
RSP: 0018:ffff8801d0c5f6c8 EFLAGS: 00000002
RAX: 0000000000000002 RBX: 000002ef9ca474eb RCX: 0000000000000000
RDX: 0000000000000004 RSI: ffffffff81b0a74c RDI: 0000000000000001
RBP: ffff8801d0c5f6e8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff83fdf198 R12: 000002ef9ca46f6e
R13: 0000000000000000 R14: 00000000000008fd R15: fffffbfff092dca5
FS: 0000000000000000(0000) GS:ffff8801db600000(0063) knlGS:00000000f7742b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f7741cbc CR3: 00000001d12f5000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
ffffffff8496e4e0 0000000000002706 0000000000000020 fffffbfff092dce3
ffff8801d0c5f6f8 ffffffff81ad88c0 ffff8801d0c5f708 ffffffff81ad88fa
ffff8801d0c5f758 ffffffff81cc411f ffffed003a18bf01 ffffffff8496e528
Call Trace:
[<ffffffff81ad88c0>] __delay+0x10/0x20 arch/x86/lib/delay.c:160
[<ffffffff81ad88fa>] __const_udelay+0x2a/0x30 arch/x86/lib/delay.c:174
[<ffffffff81cc411f>] wait_for_xmitr+0x6f/0x1e0
drivers/tty/serial/8250/8250_port.c:1725
[<ffffffff81cc42b0>] serial8250_console_putchar+0x20/0x60
drivers/tty/serial/8250/8250_port.c:2806
[<ffffffff81caf2e6>] uart_console_write+0x56/0xe0
drivers/tty/serial/serial_core.c:1789
[<ffffffff81ccdc4b>] serial8250_console_write+0x2fb/0x870
drivers/tty/serial/8250/8250_port.c:2872
[<ffffffff81cbd36f>] univ8250_console_write+0x5f/0x70
drivers/tty/serial/8250/8250_core.c:594
[<ffffffff8121c6ef>] call_console_drivers.constprop.0+0x1ef/0x3f0
kernel/printk/printk.c:1468
[<ffffffff8121fbf2>] console_unlock kernel/printk/printk.c:2335 [inline]
[<ffffffff8121fbf2>] console_unlock+0x602/0xa10 kernel/printk/printk.c:2242
[<ffffffff812203b2>] vprintk_emit+0x3b2/0x820 kernel/printk/printk.c:1837
[<ffffffff81220848>] vprintk+0x28/0x30 kernel/printk/printk.c:1848
[<ffffffff813afb69>] printk+0xc2/0xf5 kernel/printk/printk.c:1927
[<ffffffff8216a1ae>] binder_ioctl.cold+0x179/0x305
drivers/android/binder.c:4896
[<ffffffff8159aea3>] C_SYSC_ioctl fs/compat_ioctl.c:1592 [inline]
[<ffffffff8159aea3>] compat_SyS_ioctl+0x403/0x2210 fs/compat_ioctl.c:1544
[<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330
[inline]
[<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90
arch/x86/entry/common.c:397
[<ffffffff82719790>] sysenter_flags_fixed+0xd/0x1a
Code: 00 41 55 41 54 53 e8 88 47 68 ff e8 73 1f 03 00 41 89 c5 0f ae e8 0f
31 48 c1 e2 20 48 09 c2 49 89 d4 eb 16 f3 90 bf 01 00 00 00 <e8> 63 47 68
ff e8 4e 1f 03 00 44 39 e8 75 36 0f ae e8 0f 31 48

NMI backtrace for cpu 1

CPU: 1 PID: 20 Comm: khungtaskd Not tainted 4.4.171+ #12
task: ffff8801da6c4740 task.stack: ffff8801d9ef0000
RIP: 0010:[<ffffffff8109b617>] [<ffffffff8109b617>] _flat_send_IPI_mask
arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>] [<ffffffff8109b617>]
flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8801d9ef7c88 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8801d9ef7cb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00000000080fd738 CR3: 00000000b454f000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
0000000000000001 ffffffff82e5f2e0 ffffffff831a6840 fffffbfff0634be4
000000000001b6c0 0000000000000008 ffff8801d9ef7cd8 ffffffff81092bee
0000000000000008 ffffffff82924260 ffff8801d9ef7d30 ffffffff81ab7de2
Call Trace:
[<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80
arch/x86/kernel/apic/hw_nmi.c:33
[<ffffffff81ab7de2>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae
lib/nmi_backtrace.c:85
[<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20
arch/x86/kernel/apic/hw_nmi.c:38
[<ffffffff813b4556>] trigger_all_cpu_backtrace include/linux/nmi.h:44
[inline]
[<ffffffff813b4556>] check_hung_task kernel/hung_task.c:125 [inline]
[<ffffffff813b4556>] check_hung_uninterruptible_tasks
kernel/hung_task.c:182 [inline]
[<ffffffff813b4556>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
[<ffffffff811340b3>] kthread+0x273/0x310 kernel/kthread.c:211
[<ffffffff82718405>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89
fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00
02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 e1

---
This bug is generated by a bot. It may contain errors.
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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.