[syzbot] possible deadlock in process_measurement (3)

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May 10, 2021, 8:19:18 AMMay 10
to dmitry....@gmail.com, jmo...@namei.org, linux-i...@vger.kernel.org, linux-...@vger.kernel.org, linux-secu...@vger.kernel.org, se...@hallyn.com, syzkall...@googlegroups.com, zo...@linux.ibm.com
Hello,

syzbot found the following issue on:

HEAD commit: d2b6f8a1 Merge tag 'xfs-5.13-merge-3' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15f425b3d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=65c207250bba4efe
dashboard link: https://syzkaller.appspot.com/bug?extid=ccfcdc8958f74084f16d
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16079d1ed00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12280d95d00000

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

======================================================
WARNING: possible circular locking dependency detected
5.12.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor167/10873 is trying to acquire lock:
ffff8880162d0bc0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x3a8/0x17e0 security/integrity/ima/ima_main.c:253

but task is already holding lock:
ffff888147e2e460 (sb_writers#5){.+.+}-{0:0}, at: do_open fs/namei.c:3354 [inline]
ffff888147e2e460 (sb_writers#5){.+.+}-{0:0}, at: path_openat+0x1ad9/0x27e0 fs/namei.c:3494

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#5){.+.+}-{0:0}:
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1765 [inline]
sb_start_write include/linux/fs.h:1835 [inline]
mnt_want_write+0x6e/0x3e0 fs/namespace.c:375
ovl_maybe_copy_up+0x11f/0x190 fs/overlayfs/copy_up.c:995
ovl_open+0xba/0x270 fs/overlayfs/file.c:149
do_dentry_open+0x4b9/0x11b0 fs/open.c:826
vfs_open fs/open.c:940 [inline]
dentry_open+0x132/0x1d0 fs/open.c:956
ima_calc_file_hash+0x2d2/0x4b0 security/integrity/ima/ima_crypto.c:557
ima_collect_measurement+0x4ca/0x570 security/integrity/ima/ima_api.c:252
process_measurement+0xd1c/0x17e0 security/integrity/ima/ima_main.c:330
ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:499
do_open fs/namei.c:3363 [inline]
path_openat+0x15b5/0x27e0 fs/namei.c:3494
do_filp_open+0x190/0x3d0 fs/namei.c:3521
do_sys_openat2+0x16d/0x420 fs/open.c:1187
do_sys_open fs/open.c:1203 [inline]
__do_sys_open fs/open.c:1211 [inline]
__se_sys_open fs/open.c:1207 [inline]
__x64_sys_open+0x119/0x1c0 fs/open.c:1207
do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (&iint->mutex){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:2938 [inline]
check_prevs_add kernel/locking/lockdep.c:3061 [inline]
validate_chain kernel/locking/lockdep.c:3676 [inline]
__lock_acquire+0x2a17/0x5230 kernel/locking/lockdep.c:4902
lock_acquire kernel/locking/lockdep.c:5512 [inline]
lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5477
__mutex_lock_common kernel/locking/mutex.c:949 [inline]
__mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
process_measurement+0x3a8/0x17e0 security/integrity/ima/ima_main.c:253
ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:499
do_open fs/namei.c:3363 [inline]
path_openat+0x15b5/0x27e0 fs/namei.c:3494
do_filp_open+0x190/0x3d0 fs/namei.c:3521
do_sys_openat2+0x16d/0x420 fs/open.c:1187
do_sys_open fs/open.c:1203 [inline]
__do_sys_open fs/open.c:1211 [inline]
__se_sys_open fs/open.c:1207 [inline]
__x64_sys_open+0x119/0x1c0 fs/open.c:1207
do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(sb_writers#5);
lock(&iint->mutex);
lock(sb_writers#5);
lock(&iint->mutex);

*** DEADLOCK ***

1 lock held by syz-executor167/10873:
#0: ffff888147e2e460 (sb_writers#5){.+.+}-{0:0}, at: do_open fs/namei.c:3354 [inline]
#0: ffff888147e2e460 (sb_writers#5){.+.+}-{0:0}, at: path_openat+0x1ad9/0x27e0 fs/namei.c:3494

stack backtrace:
CPU: 1 PID: 10873 Comm: syz-executor167 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2129
check_prev_add kernel/locking/lockdep.c:2938 [inline]
check_prevs_add kernel/locking/lockdep.c:3061 [inline]
validate_chain kernel/locking/lockdep.c:3676 [inline]
__lock_acquire+0x2a17/0x5230 kernel/locking/lockdep.c:4902
lock_acquire kernel/locking/lockdep.c:5512 [inline]
lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5477
__mutex_lock_common kernel/locking/mutex.c:949 [inline]
__mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
process_measurement+0x3a8/0x17e0 security/integrity/ima/ima_main.c:253
ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:499
do_open fs/namei.c:3363 [inline]
path_openat+0x15b5/0x27e0 fs/namei.c:3494
do_filp_open+0x190/0x3d0 fs/namei.c:3521
do_sys_openat2+0x16d/0x420 fs/open.c:1187
do_sys_open fs/open.c:1203 [inline]
__do_sys_open fs/open.c:1211 [inline]
__se_sys_open fs/open.c:1207 [inline]
__x64_sys_open+0x119/0x1c0 fs/open.c:1207
do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x446119
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff688b472f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00000000004cb4c0 RCX: 0000000000446119
RDX: 0000000000000000 RSI: 0000000000000300 RDI: 0000000020000040
RBP: 000000000049b06c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 3d72696472657070 R14: 0079616c7265766f R15: 00000000004cb4c8


---
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