Hello,
syzbot found the following crash on:
HEAD commit: 46c163a036b4 Add linux-next specific files for 20180921
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1283fef1400000
kernel config: https://syzkaller.appspot.com/x/.config?x=20ea07a946ad19d7
dashboard link: https://syzkaller.appspot.com/bug?extid=0e7e90fff14568b11ebe
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13d6792a400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1610b21a400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+0e7e90fff14568b11ebe@xxxxxxxxxxxxxxxxxxxxxxxxx
INFO: task jbd2/sda1-8:3307 blocked for more than 140 seconds.
Not tainted 4.19.0-rc4-next-20180921+ #77
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
jbd2/sda1-8 D18264 3307 2 0x80000000
Call Trace:
context_switch kernel/sched/core.c:2830 [inline]
__schedule+0x86c/0x1ed0 kernel/sched/core.c:3479
schedule+0xfe/0x460 kernel/sched/core.c:3523
jbd2_journal_commit_transaction+0xd38/0x89da fs/jbd2/commit.c:435
kjournald2+0x26d/0xb30 fs/jbd2/journal.c:229
kthread+0x35a/0x440 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Showing all locks held in the system:
4 locks held by kworker/u4:2/28:
#0: 00000000966b2f63 ((wq_completion)"writeback"){+.+.}, at:
__write_once_size include/linux/compiler.h:215 [inline]
#0: 00000000966b2f63 ((wq_completion)"writeback"){+.+.}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 00000000966b2f63 ((wq_completion)"writeback"){+.+.}, at: atomic64_set
include/asm-generic/atomic-instrumented.h:40 [inline]
#0: 00000000966b2f63 ((wq_completion)"writeback"){+.+.}, at:
atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
#0: 00000000966b2f63 ((wq_completion)"writeback"){+.+.}, at: set_work_data
kernel/workqueue.c:617 [inline]
#0: 00000000966b2f63 ((wq_completion)"writeback"){+.+.}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
#0: 00000000966b2f63 ((wq_completion)"writeback"){+.+.}, at:
process_one_work+0xb43/0x1b80 kernel/workqueue.c:2124
#1: 00000000544b3bff ((work_completion)(&(&wb->dwork)->work)){+.+.}, at:
process_one_work+0xb9a/0x1b80 kernel/workqueue.c:2128
#2: 000000008f6094aa (&fc->fs_type->s_umount_key#30){++++}, at:
trylock_super+0x22/0x110 fs/super.c:411
#3: 00000000e88adbe2 (&sbi->s_journal_flag_rwsem){.+.+}, at:
do_writepages+0x9a/0x1a0 mm/page-writeback.c:2340
1 lock held by khungtaskd/983:
#0: 000000004a02f480 (rcu_read_lock){....}, at:
debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435
3 locks held by rs:main Q:Reg/5445:
#0: 0000000076c9764a (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200
fs/file.c:766
#1: 000000004aae268a (sb_writers#5){.+.+}, at: file_start_write
include/linux/fs.h:2784 [inline]
#1: 000000004aae268a (sb_writers#5){.+.+}, at: vfs_write+0x42a/0x560
fs/read_write.c:548
#2: 0000000092898058 (&sb->s_type->i_mutex_key#12){+.+.}, at:
inode_trylock include/linux/fs.h:770 [inline]
#2: 0000000092898058 (&sb->s_type->i_mutex_key#12){+.+.}, at:
ext4_file_write_iter+0x2a1/0x1420 fs/ext4/file.c:232
1 lock held by rsyslogd/5448:
#0: 000000000182ebfe (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200
fs/file.c:766
2 locks held by getty/5537:
#0: 000000002db97c95 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000c978bc9a (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5538:
#0: 0000000026d5a3f0 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000858cc8d0 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5539:
#0: 000000004b6a537d (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 0000000092120c7f (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5540:
#0: 0000000032437300 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000af9d3d4d (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5541:
#0: 000000003cb32a3a (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 0000000089bab666 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5542:
#0: 0000000084a4d130 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000764db77e (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5543:
#0: 00000000c92252aa (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 000000009cc43f77 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
6 locks held by syz-executor386/5564:
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 983 Comm: khungtaskd Not tainted 4.19.0-rc4-next-20180921+ #77
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+0x1d3/0x2c4 lib/dump_stack.c:113
nmi_cpu_backtrace.cold.4+0x63/0xa2 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1c2/0x22c 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:144 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline]
watchdog+0xb39/0x1050 kernel/hung_task.c:265
kthread+0x35a/0x440 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 0 to CPUs 1:
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.188
msecs
NMI backtrace for cpu 1
CPU: 1 PID: 5564 Comm: syz-executor386 Not tainted
4.19.0-rc4-next-20180921+ #77
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:ext4_ext_drop_refs+0xc0/0xf0 fs/ext4/extents.c:723
Code: 03 00 00 00 00 e8 70 31 6c ff 41 83 c4 01 44 89 f7 48 83 c3 30 44 89
e6 e8 ed 31 6c ff 45 39 e6 7d a6 e8 53 31 6c ff 5b 41 5c <41> 5d 41 5e 41
5f 5d c3 e8 a3 aa af ff e9 76 ff ff ff 48 89 df e8
RSP: 0018:ffff8801be77f198 EFLAGS: 00000293
RAX: ffff8801d8708580 RBX: ffff8801be363a80 RCX: ffffffff82111fd3
RDX: 0000000000000000 RSI: ffffffff82111fdd RDI: 0000000000000004
RBP: ffff8801be77f1b0 R08: ffff8801d8708580 R09: ffffed003b585b57
R10: ffffed003b585b57 R11: ffff8801dac2dabb R12: 0000000000008002
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000000000b12880(0000) GS:ffff8801dad00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600400 CR3: 00000001d8736000 CR4: 00000000001406e0
Call Trace:
mext_check_coverage.constprop.13+0x27b/0x510 fs/ext4/move_extent.c:105
move_extent_per_page fs/ext4/move_extent.c:323 [inline]
ext4_move_extents+0x2784/0x3c20 fs/ext4/move_extent.c:669
ext4_ioctl+0x314f/0x4210 fs/ext4/ioctl.c:799
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440169
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe0bdc36e8 EFLAGS: 00000217 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440169
RDX: 0000000020000040 RSI: 00000000c028660f RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000217 R12: 00000000004019f0
R13: 0000000000401a80 R14: 0000000000000000 R15: 0000000000000000
---
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