possible deadlock in ovl_write_iter

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syzbot

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Apr 17, 2019, 11:08:06 PM4/17/19
to syzkaller...@googlegroups.com
Hello,

syzbot found the following crash on:

HEAD commit: 4b0e041c Linux 4.19.35
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10938e67200000
kernel config: https://syzkaller.appspot.com/x/.config?x=bb1bcac868b1655e
dashboard link: https://syzkaller.appspot.com/bug?extid=baff7daddde4737f68b5
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+baff7d...@syzkaller.appspotmail.com

overlayfs: './file0' not a directory
Process accounting resumed
======================================================
netlink: 'syz-executor.3': attribute type 15 has an invalid length.
WARNING: possible circular locking dependency detected
4.19.35 #3 Not tainted
------------------------------------------------------
syz-executor.1/26193 is trying to acquire lock:
00000000080b6233 (&ovl_i_mutex_key[depth]){+.+.}, at: inode_lock
include/linux/fs.h:738 [inline]
00000000080b6233 (&ovl_i_mutex_key[depth]){+.+.}, at:
ovl_write_iter+0x148/0xc20 fs/overlayfs/file.c:231

but task is already holding lock:
000000004ccdd87f
netlink: 'syz-executor.3': attribute type 21 has an invalid length.
(&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161 [inline]
(&acct->lock#2){+.+.}, at: slow_acct_process kernel/acct.c:577 [inline]
(&acct->lock#2){+.+.}, at: acct_process+0x2e5/0x61e kernel/acct.c:605

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&acct->lock#2){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:925 [inline]
__mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
acct_pin_kill+0x27/0x100 kernel/acct.c:173
pin_kill+0x18f/0x860 fs/fs_pin.c:50
acct_on+0x574/0x790 kernel/acct.c:254
__do_sys_acct kernel/acct.c:286 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xae/0x200 kernel/acct.c:273
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #1 (sb_writers#4){.+.+}:
percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36
[inline]
percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
__sb_start_write+0x20b/0x360 fs/super.c:1387
sb_start_write include/linux/fs.h:1569 [inline]
mnt_want_write+0x3f/0xc0 fs/namespace.c:360
ovl_want_write+0x76/0xa0 fs/overlayfs/util.c:24
ovl_link+0x7c/0x2d5 fs/overlayfs/dir.c:674
vfs_link+0x7a4/0xb60 fs/namei.c:4240
do_linkat+0x550/0x770 fs/namei.c:4308
__do_sys_link fs/namei.c:4337 [inline]
__se_sys_link fs/namei.c:4335 [inline]
__x64_sys_link+0x61/0x80 fs/namei.c:4335
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (&ovl_i_mutex_key[depth]){+.+.}:
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3903
down_write+0x38/0x90 kernel/locking/rwsem.c:70
inode_lock include/linux/fs.h:738 [inline]
ovl_write_iter+0x148/0xc20 fs/overlayfs/file.c:231
call_write_iter include/linux/fs.h:1811 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x58e/0x820 fs/read_write.c:487
__kernel_write+0x110/0x390 fs/read_write.c:506
do_acct_process+0xd37/0x1150 kernel/acct.c:520
slow_acct_process kernel/acct.c:579 [inline]
acct_process+0x568/0x61e kernel/acct.c:605
do_exit+0x17c0/0x2fa0 kernel/exit.c:866
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

other info that might help us debug this:

Chain exists of:
&ovl_i_mutex_key[depth] --> sb_writers#4 --> &acct->lock#2

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&acct->lock#2);
lock(sb_writers#4);
lock(&acct->lock#2);
lock(&ovl_i_mutex_key[depth]);

*** DEADLOCK ***

2 locks held by syz-executor.1/26193:
#0: 000000004ccdd87f (&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161
[inline]
#0: 000000004ccdd87f (&acct->lock#2){+.+.}, at: slow_acct_process
kernel/acct.c:577 [inline]
#0: 000000004ccdd87f (&acct->lock#2){+.+.}, at: acct_process+0x2e5/0x61e
kernel/acct.c:605
#1: 000000003f46019f (sb_writers#20){.+.+}, at: file_start_write_trylock
include/linux/fs.h:2771 [inline]
#1: 000000003f46019f (sb_writers#20){.+.+}, at:
do_acct_process+0xf37/0x1150 kernel/acct.c:517

stack backtrace:
CPU: 1 PID: 26193 Comm: syz-executor.1 Not tainted 4.19.35 #3
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
print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1221
check_prev_add kernel/locking/lockdep.c:1861 [inline]
check_prevs_add kernel/locking/lockdep.c:1974 [inline]
validate_chain kernel/locking/lockdep.c:2415 [inline]
__lock_acquire+0x2e6d/0x48f0 kernel/locking/lockdep.c:3411
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3903
down_write+0x38/0x90 kernel/locking/rwsem.c:70
inode_lock include/linux/fs.h:738 [inline]
ovl_write_iter+0x148/0xc20 fs/overlayfs/file.c:231
call_write_iter include/linux/fs.h:1811 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x58e/0x820 fs/read_write.c:487
__kernel_write+0x110/0x390 fs/read_write.c:506
do_acct_process+0xd37/0x1150 kernel/acct.c:520
slow_acct_process kernel/acct.c:579 [inline]
acct_process+0x568/0x61e kernel/acct.c:605
do_exit+0x17c0/0x2fa0 kernel/exit.c:866
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: 0033:0x458c29
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
RSP: 002b:00007ffcc2dc4d38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000000000000001e RCX: 0000000000458c29
RDX: 00000000004129e1 RSI: fffffffffffffff7 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000000001b7725 R09: 00007ffcc2dc4d90
R10: 00000000001b7725 R11: 0000000000000246 R12: 0000000000000001
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
R13: 00007ffcc2dc4d90 R14: 0000000000000000 R15: 00007ffcc2dc4da0
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
net_ratelimit: 21 callbacks suppressed
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
validate_nla: 26 callbacks suppressed
netlink: 'syz-executor.3': attribute type 15 has an invalid length.
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
netlink: 'syz-executor.3': attribute type 21 has an invalid length.
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
netlink: 'syz-executor.3': attribute type 3 has an invalid length.
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_1
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_0
netlink: 'syz-executor.3': attribute type 15 has an invalid length.
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
netlink: 'syz-executor.3': attribute type 21 has an invalid length.
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
netlink: 'syz-executor.0': attribute type 15 has an invalid length.
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
netlink: 'syz-executor.0': attribute type 21 has an invalid length.
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
netlink: 'syz-executor.0': attribute type 3 has an invalid length.
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
netlink: 'syz-executor.3': attribute type 15 has an invalid length.
netlink: 'syz-executor.3': attribute type 21 has an invalid length.
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
netlink: 37 bytes leftover after parsing attributes in process
`syz-executor.3'.
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
netlink: 37 bytes leftover after parsing attributes in process
`syz-executor.3'.
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
net_ratelimit: 17 callbacks suppressed
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_1
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
netlink: 25 bytes leftover after parsing attributes in process
`syz-executor.3'.
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
netlink: 1 bytes leftover after parsing attributes in process
`syz-executor.3'.
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
netlink: 57 bytes leftover after parsing attributes in process
`syz-executor.3'.
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
netlink: 57 bytes leftover after parsing attributes in process
`syz-executor.3'.
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
validate_nla: 135 callbacks suppressed
netlink: 'syz-executor.3': attribute type 15 has an invalid length.
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
netlink: 'syz-executor.3': attribute type 21 has an invalid length.
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
netlink: 'syz-executor.3': attribute type 3 has an invalid length.
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
netlink: 'syz-executor.3': attribute type 15 has an invalid length.
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
netlink: 'syz-executor.3': attribute type 21 has an invalid length.
netlink: 'syz-executor.3': attribute type 3 has an invalid length.
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
netlink: 'syz-executor.0': attribute type 15 has an invalid length.
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
netlink: 37 bytes leftover after parsing attributes in process
`syz-executor.0'.
kobject: 'loop4' (000000003cee5cf2): kobject_uevent_env
kobject: 'loop4' (000000003cee5cf2): fill_kobj_path: path
= '/devices/virtual/block/loop4'
protocol 88fb is buggy, dev hsr_slave_0
netlink: 'syz-executor.3': attribute type 15 has an invalid length.
netlink: 'syz-executor.3': attribute type 21 has an invalid length.
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
netlink: 'syz-executor.3': attribute type 3 has an invalid length.
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
netlink: 37 bytes leftover after parsing attributes in process
`syz-executor.0'.
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
netlink: 37 bytes leftover after parsing attributes in process
`syz-executor.0'.
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env
kobject: 'loop1' (00000000a87acd3f): fill_kobj_path: path
= '/devices/virtual/block/loop1'
kobject: 'loop5' (00000000b3f2feb0): kobject_uevent_env
kobject: 'loop5' (00000000b3f2feb0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
kobject: 'loop1' (00000000a87acd3f): kobject_uevent_env


---
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

unread,
Apr 29, 2019, 3:06:06 AM4/29/19
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following crash on:

HEAD commit: 19bb613a Linux 4.19.37
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12e56942a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=2f4f1677ff80cdff
dashboard link: https://syzkaller.appspot.com/bug?extid=baff7daddde4737f68b5
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=165f39a8a00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+baff7d...@syzkaller.appspotmail.com

overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
======================================================
Process accounting resumed
WARNING: possible circular locking dependency detected
4.19.37 #5 Not tainted
------------------------------------------------------
syz-executor.4/16409 is trying to acquire lock:
000000004457f15c (sb_writers#4){.+.+}, at: file_start_write
include/linux/fs.h:2764 [inline]
000000004457f15c (sb_writers#4){.+.+}, at: ovl_write_iter+0x91b/0xc20
fs/overlayfs/file.c:243

but task is already holding lock:
overlayfs: './file0' not a directory
00000000f23e5990 (&ovl_i_mutex_key[depth]){+.+.}, at: inode_lock
include/linux/fs.h:738 [inline]
00000000f23e5990 (&ovl_i_mutex_key[depth]){+.+.}, at:
ovl_write_iter+0x148/0xc20 fs/overlayfs/file.c:231

which lock already depends on the new lock.

overlayfs: './file0' not a directory

the existing dependency chain (in reverse order) is:

-> #2 (&ovl_i_mutex_key[depth]){+.+.}:
down_write+0x38/0x90 kernel/locking/rwsem.c:70
inode_lock include/linux/fs.h:738 [inline]
ovl_write_iter+0x148/0xc20 fs/overlayfs/file.c:231
Process accounting resumed
call_write_iter include/linux/fs.h:1811 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x58e/0x820 fs/read_write.c:487
__kernel_write+0x110/0x390 fs/read_write.c:506
Process accounting resumed
do_acct_process+0xd37/0x1150 kernel/acct.c:520
slow_acct_process kernel/acct.c:579 [inline]
acct_process+0x568/0x61e kernel/acct.c:605
Process accounting resumed
do_exit+0x17c0/0x2fa0 kernel/exit.c:866
do_group_exit+0x135/0x370 kernel/exit.c:979
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
get_signal+0x399/0x1d50 kernel/signal.c:2572
Process accounting resumed
do_signal+0x95/0x1950 arch/x86/kernel/signal.c:816
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
overlayfs: './file0' not a directory
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #1 (
Process accounting resumed
&acct->lock#2){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:925 [inline]
__mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
kobject: 'loop1' (000000004fd93cd8): kobject_uevent_env
acct_pin_kill+0x27/0x100 kernel/acct.c:173
kobject: 'loop1' (000000004fd93cd8): fill_kobj_path: path
= '/devices/virtual/block/loop1'
pin_kill+0x18f/0x860 fs/fs_pin.c:50
acct_on+0x574/0x790 kernel/acct.c:254
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
__do_sys_acct kernel/acct.c:286 [inline]
__se_sys_acct kernel/acct.c:273 [inline]
__x64_sys_acct+0xae/0x200 kernel/acct.c:273
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (sb_writers#4){.+.+}:
kobject: 'loop2' (000000000dfd4aa7): kobject_uevent_env
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3900
percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36
[inline]
percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
__sb_start_write+0x20b/0x360 fs/super.c:1387
kobject: 'loop2' (000000000dfd4aa7): fill_kobj_path: path
= '/devices/virtual/block/loop2'
file_start_write include/linux/fs.h:2764 [inline]
ovl_write_iter+0x91b/0xc20 fs/overlayfs/file.c:243
call_write_iter include/linux/fs.h:1811 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x58e/0x820 fs/read_write.c:487
__kernel_write+0x110/0x390 fs/read_write.c:506
do_acct_process+0xd37/0x1150 kernel/acct.c:520
slow_acct_process kernel/acct.c:579 [inline]
acct_process+0x568/0x61e kernel/acct.c:605
do_exit+0x17c0/0x2fa0 kernel/exit.c:866
do_group_exit+0x135/0x370 kernel/exit.c:979
get_signal+0x399/0x1d50 kernel/signal.c:2572
do_signal+0x95/0x1950 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Chain exists of:
sb_writers#4 --> &acct->lock#2 --> &ovl_i_mutex_key[depth]

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ovl_i_mutex_key[depth]);
lock(&acct->lock#2);
lock(&ovl_i_mutex_key[depth]);
lock(sb_writers#4);

*** DEADLOCK ***

3 locks held by syz-executor.4/16409:
#0: 00000000ca3023ab (&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161
[inline]
#0: 00000000ca3023ab (&acct->lock#2){+.+.}, at: slow_acct_process
kernel/acct.c:577 [inline]
#0: 00000000ca3023ab (&acct->lock#2){+.+.}, at: acct_process+0x2e5/0x61e
kernel/acct.c:605
#1: 00000000ed439905 (sb_writers#13){.+.+}, at: file_start_write_trylock
include/linux/fs.h:2771 [inline]
#1: 00000000ed439905 (sb_writers#13){.+.+}, at:
do_acct_process+0xf37/0x1150 kernel/acct.c:517
#2: 00000000f23e5990 (&ovl_i_mutex_key[depth]){+.+.}, at: inode_lock
include/linux/fs.h:738 [inline]
#2: 00000000f23e5990 (&ovl_i_mutex_key[depth]){+.+.}, at:
ovl_write_iter+0x148/0xc20 fs/overlayfs/file.c:231

stack backtrace:
CPU: 1 PID: 16409 Comm: syz-executor.4 Not tainted 4.19.37 #5
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
print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1221
check_prev_add kernel/locking/lockdep.c:1861 [inline]
check_prevs_add kernel/locking/lockdep.c:1974 [inline]
validate_chain kernel/locking/lockdep.c:2415 [inline]
__lock_acquire+0x2e6d/0x48f0 kernel/locking/lockdep.c:3411
lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3900
percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline]
percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
__sb_start_write+0x20b/0x360 fs/super.c:1387
file_start_write include/linux/fs.h:2764 [inline]
ovl_write_iter+0x91b/0xc20 fs/overlayfs/file.c:243
call_write_iter include/linux/fs.h:1811 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x58e/0x820 fs/read_write.c:487
__kernel_write+0x110/0x390 fs/read_write.c:506
do_acct_process+0xd37/0x1150 kernel/acct.c:520
slow_acct_process kernel/acct.c:579 [inline]
acct_process+0x568/0x61e kernel/acct.c:605
do_exit+0x17c0/0x2fa0 kernel/exit.c:866
do_group_exit+0x135/0x370 kernel/exit.c:979
get_signal+0x399/0x1d50 kernel/signal.c:2572
do_signal+0x95/0x1950 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458da9
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fe499550cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000073bfa8 RCX: 0000000000458da9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000073bfa8
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000073bfac
R13: 00007ffc240ff03f R14: 00007fe4995519c0 R15: 000000000073bfac
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
Process accounting resumed
Process accounting resumed
kobject: 'loop2' (000000000dfd4aa7): kobject_uevent_env
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop2' (000000000dfd4aa7): fill_kobj_path: path
= '/devices/virtual/block/loop2'
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
Process accounting resumed
kobject: 'loop4' (000000001b7420bb): kobject_uevent_env
overlayfs: './file0' not a directory
kobject: 'loop4' (000000001b7420bb): fill_kobj_path: path
= '/devices/virtual/block/loop4'
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop3' (00000000880352cf): kobject_uevent_env
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop3' (00000000880352cf): fill_kobj_path: path
= '/devices/virtual/block/loop3'
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
overlayfs: './file0' not a directory
kobject: 'loop1' (000000004fd93cd8): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop1' (000000004fd93cd8): fill_kobj_path: path
= '/devices/virtual/block/loop1'
Process accounting resumed
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop4' (000000001b7420bb): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop4' (000000001b7420bb): fill_kobj_path: path
= '/devices/virtual/block/loop4'
Process accounting resumed
Process accounting resumed
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop3' (00000000880352cf): kobject_uevent_env
kauditd_printk_skb: 141 callbacks suppressed
audit: type=1804 audit(1556521050.622:2599): pid=16527 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.4"
name="/root/syzkaller-testdir175988685/syzkaller.Xbr9Za/431/file0"
dev="sda1" ino=16643 res=1
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop3' (00000000880352cf): fill_kobj_path: path
= '/devices/virtual/block/loop3'
Process accounting resumed
kobject: 'loop1' (000000004fd93cd8): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
audit: type=1804 audit(1556521050.692:2600): pid=16532 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.0"
name="/root/syzkaller-testdir733048634/syzkaller.yUAzpd/447/file0"
dev="sda1" ino=16721 res=1
kobject: 'loop1' (000000004fd93cd8): fill_kobj_path: path
= '/devices/virtual/block/loop1'
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
audit: type=1804 audit(1556521050.712:2601): pid=16529 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.5"
name="/root/syzkaller-testdir232567175/syzkaller.oMOuQ8/437/file0"
dev="sda1" ino=16581 res=1
kobject: 'loop2' (000000000dfd4aa7): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
audit: type=1804 audit(1556521050.752:2602): pid=16535 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.1"
name="/root/syzkaller-testdir378415304/syzkaller.fBZ0Da/425/file0"
dev="sda1" ino=16533 res=1
Process accounting resumed
Process accounting resumed
kobject: 'loop2' (000000000dfd4aa7): fill_kobj_path: path
= '/devices/virtual/block/loop2'
overlayfs: './file0' not a directory
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
Process accounting resumed
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
Process accounting resumed
overlayfs: './file0' not a directory
audit: type=1804 audit(1556521050.762:2603): pid=16539 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.3"
name="/root/syzkaller-testdir637840038/syzkaller.2RGt19/422/file0"
dev="sda1" ino=16626 res=1
Process accounting resumed
audit: type=1804 audit(1556521050.762:2604): pid=16537 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.0"
name="/root/syzkaller-testdir733048634/syzkaller.yUAzpd/448/file0"
dev="sda1" ino=16577 res=1
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
Process accounting resumed
kobject: 'loop1' (000000004fd93cd8): kobject_uevent_env
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop1' (000000004fd93cd8): fill_kobj_path: path
= '/devices/virtual/block/loop1'
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
audit: type=1804 audit(1556521050.792:2605): pid=16541 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.4"
name="/root/syzkaller-testdir175988685/syzkaller.Xbr9Za/432/file0"
dev="sda1" ino=16642 res=1
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
Process accounting resumed
kobject: 'loop3' (00000000880352cf): kobject_uevent_env
Process accounting resumed
kobject: 'loop3' (00000000880352cf): fill_kobj_path: path
= '/devices/virtual/block/loop3'
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop1' (000000004fd93cd8): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
audit: type=1804 audit(1556521050.792:2606): pid=16543 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.2"
name="/root/syzkaller-testdir726457169/syzkaller.rKu2xf/431/file0"
dev="sda1" ino=16643 res=1
kobject: 'loop1' (000000004fd93cd8): fill_kobj_path: path
= '/devices/virtual/block/loop1'
Process accounting resumed
Process accounting resumed
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
audit: type=1804 audit(1556521050.812:2607): pid=16545 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.0"
name="/root/syzkaller-testdir733048634/syzkaller.yUAzpd/449/file0"
dev="sda1" ino=16546 res=1
Process accounting resumed
kobject: 'loop2' (000000000dfd4aa7): kobject_uevent_env
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
Process accounting resumed
kobject: 'loop2' (000000000dfd4aa7): fill_kobj_path: path
= '/devices/virtual/block/loop2'
audit: type=1804 audit(1556521050.852:2608): pid=16549 uid=0
auid=4294967295 ses=4294967295
subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr
cause=ToMToU comm="syz-executor.5"
name="/root/syzkaller-testdir232567175/syzkaller.oMOuQ8/438/file0"
dev="sda1" ino=16690 res=1
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop3' (00000000880352cf): kobject_uevent_env
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop3' (00000000880352cf): fill_kobj_path: path
= '/devices/virtual/block/loop3'
overlayfs: './file0' not a directory
kobject: 'loop2' (000000000dfd4aa7): kobject_uevent_env
Process accounting resumed
kobject: 'loop2' (000000000dfd4aa7): fill_kobj_path: path
= '/devices/virtual/block/loop2'
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
Process accounting resumed
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop1' (000000004fd93cd8): kobject_uevent_env
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop1' (000000004fd93cd8): fill_kobj_path: path
= '/devices/virtual/block/loop1'
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop4' (000000001b7420bb): kobject_uevent_env
Process accounting resumed
kobject: 'loop4' (000000001b7420bb): fill_kobj_path: path
= '/devices/virtual/block/loop4'
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop2' (000000000dfd4aa7): kobject_uevent_env
overlayfs: './file0' not a directory
kobject: 'loop2' (000000000dfd4aa7): fill_kobj_path: path
= '/devices/virtual/block/loop2'
Process accounting resumed
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop0' (0000000073a10532): fill_kobj_path: path
= '/devices/virtual/block/loop0'
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop1' (000000004fd93cd8): kobject_uevent_env
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
kobject: 'loop1' (000000004fd93cd8): fill_kobj_path: path
= '/devices/virtual/block/loop1'
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
Process accounting resumed
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
kobject: 'loop4' (000000001b7420bb): kobject_uevent_env
Process accounting resumed
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
Process accounting resumed
overlayfs: './file0' not a directory
kobject: 'loop4' (000000001b7420bb): fill_kobj_path: path
= '/devices/virtual/block/loop4'
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
overlayfs: './file0' not a directory
Process accounting resumed
Process accounting resumed
Process accounting resumed
Process accounting resumed
kobject: 'loop2' (000000000dfd4aa7): kobject_uevent_env
overlayfs: './file0' not a directory
kobject: 'loop2' (000000000dfd4aa7): fill_kobj_path: path
= '/devices/virtual/block/loop2'
Process accounting resumed
kobject: 'loop5' (00000000d2a29a43): kobject_uevent_env
kobject: 'loop5' (00000000d2a29a43): fill_kobj_path: path
= '/devices/virtual/block/loop5'
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): kobject_uevent_env
overlayfs: './file0' not a directory
kobject: 'loop0' (0000000073a10532): fill_k

syzbot

unread,
Dec 18, 2019, 5:55:01 PM12/18/19
to syzkaller...@googlegroups.com
syzbot suspects this bug was fixed by commit:

commit ab69a230421065b48ef93d3e6daf332e71c931dc
Author: David S. Miller <da...@davemloft.net>
Date: Fri May 17 19:15:05 2019 +0000

Revert "tipc: fix modprobe tipc failed after switch order of device
registration"

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16682db6e00000
start commit: 19bb613a Linux 4.19.37
git tree: linux-4.19.y
kernel config: https://syzkaller.appspot.com/x/.config?x=2f4f1677ff80cdff
dashboard link: https://syzkaller.appspot.com/bug?extid=baff7daddde4737f68b5
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=165f39a8a00000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: Revert "tipc: fix modprobe tipc failed after switch order of
device registration"

For information about bisection process see: https://goo.gl/tpsmEJ#bisection
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