Re: possible deadlock in process_measurement (2)
From: syzbot
Date: Sat Jun 27 2020 - 23:31:18 EST
syzbot has found a reproducer for the following crash on:
HEAD commit: 1590a2e1 Merge tag 'acpi-5.8-rc3' of git://git.kernel.org/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=164b959b100000
kernel config: https://syzkaller.appspot.com/x/.config?x=20c907630cbdbe5
dashboard link: https://syzkaller.appspot.com/bug?extid=18a1619cceea30ed45af
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=117f43c5100000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17cbb239100000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+18a1619cceea30ed45af@xxxxxxxxxxxxxxxxxxxxxxxxx
======================================================
WARNING: possible circular locking dependency detected
5.8.0-rc2-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor165/6816 is trying to acquire lock:
ffff888092f48080 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x66d/0x18e0 security/integrity/ima/ima_main.c:247
but task is already holding lock:
ffff888214040450 (sb_writers#4){.+.+}-{0:0}, at: sb_start_write include/linux/fs.h:1664 [inline]
ffff888214040450 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x45/0x90 fs/namespace.c:354
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (sb_writers#4){.+.+}-{0:0}:
lock_acquire+0x160/0x720 kernel/locking/lockdep.c:4959
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write+0x14b/0x410 fs/super.c:1672
sb_start_write include/linux/fs.h:1664 [inline]
mnt_want_write+0x45/0x90 fs/namespace.c:354
ovl_maybe_copy_up+0x117/0x180 fs/overlayfs/copy_up.c:961
ovl_open+0xa2/0x200 fs/overlayfs/file.c:145
do_dentry_open+0x813/0x1070 fs/open.c:828
vfs_open fs/open.c:942 [inline]
dentry_open+0xc6/0x120 fs/open.c:958
ima_calc_file_hash+0xfa/0x1f30 security/integrity/ima/ima_crypto.c:557
ima_collect_measurement+0x1fd/0x490 security/integrity/ima/ima_api.c:250
process_measurement+0xddf/0x18e0 security/integrity/ima/ima_main.c:324
ima_file_check+0x9c/0xe0 security/integrity/ima/ima_main.c:492
do_open fs/namei.c:3245 [inline]
path_openat+0x27d6/0x37f0 fs/namei.c:3360
do_filp_open+0x191/0x3a0 fs/namei.c:3387
do_sys_openat2+0x463/0x770 fs/open.c:1179
do_sys_open fs/open.c:1195 [inline]
ksys_open include/linux/syscalls.h:1388 [inline]
__do_sys_open fs/open.c:1201 [inline]
__se_sys_open fs/open.c:1199 [inline]
__x64_sys_open+0x1af/0x1e0 fs/open.c:1199
do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9
-> #0 (&iint->mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:2496 [inline]
check_prevs_add kernel/locking/lockdep.c:2601 [inline]
validate_chain+0x1b0c/0x8920 kernel/locking/lockdep.c:3218
__lock_acquire+0x116c/0x2c30 kernel/locking/lockdep.c:4380
lock_acquire+0x160/0x720 kernel/locking/lockdep.c:4959
__mutex_lock_common+0x189/0x2fc0 kernel/locking/mutex.c:956
__mutex_lock kernel/locking/mutex.c:1103 [inline]
mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118
process_measurement+0x66d/0x18e0 security/integrity/ima/ima_main.c:247
ima_file_check+0x9c/0xe0 security/integrity/ima/ima_main.c:492
do_open fs/namei.c:3245 [inline]
path_openat+0x27d6/0x37f0 fs/namei.c:3360
do_filp_open+0x191/0x3a0 fs/namei.c:3387
do_sys_openat2+0x463/0x770 fs/open.c:1179
do_sys_open fs/open.c:1195 [inline]
__do_sys_openat fs/open.c:1209 [inline]
__se_sys_openat fs/open.c:1204 [inline]
__x64_sys_openat+0x1c8/0x1f0 fs/open.c:1204
do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sb_writers#4);
lock(&iint->mutex);
lock(sb_writers#4);
lock(&iint->mutex);
*** DEADLOCK ***
1 lock held by syz-executor165/6816:
#0: ffff888214040450 (sb_writers#4){.+.+}-{0:0}, at: sb_start_write include/linux/fs.h:1664 [inline]
#0: ffff888214040450 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x45/0x90 fs/namespace.c:354
stack backtrace:
CPU: 1 PID: 6816 Comm: syz-executor165 Not tainted 5.8.0-rc2-syzkaller #0
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+0x1f0/0x31e lib/dump_stack.c:118
print_circular_bug+0xc72/0xea0 kernel/locking/lockdep.c:1703
check_noncircular+0x1fb/0x3a0 kernel/locking/lockdep.c:1827
check_prev_add kernel/locking/lockdep.c:2496 [inline]
check_prevs_add kernel/locking/lockdep.c:2601 [inline]
validate_chain+0x1b0c/0x8920 kernel/locking/lockdep.c:3218
__lock_acquire+0x116c/0x2c30 kernel/locking/lockdep.c:4380
lock_acquire+0x160/0x720 kernel/locking/lockdep.c:4959
__mutex_lock_common+0x189/0x2fc0 kernel/locking/mutex.c:956
__mutex_lock kernel/locking/mutex.c:1103 [inline]
mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118
process_measurement+0x66d/0x18e0 security/integrity/ima/ima_main.c:247
ima_file_check+0x9c/0xe0 security/integrity/ima/ima_main.c:492
do_open fs/namei.c:3245 [inline]
path_openat+0x27d6/0x37f0 fs/namei.c:3360
do_filp_open+0x191/0x3a0 fs/namei.c:3387
do_sys_openat2+0x463/0x770 fs/open.c:1179
do_sys_open fs/open.c:1195 [inline]
__do_sys_openat fs/open.c:1209 [inline]
__se_sys_openat fs/open.c:1204 [inline]
__x64_sys_openat+0x1c8/0x1f0 fs/open.c:1204
do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446289
Code: Bad RIP value.
RSP: 002b:00007fc5eb6ccdb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000006dbc48 RCX: 0000000000446289
RDX: 000000000000275a RSI: 00000000200001c0 RDI: 00000000ffffff9c
RBP: 00000000006dbc40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000