syzbot

======================================================
WARNING: possible circular locking dependency detected
5.14.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor453/8406 is trying to acquire lock:
ffff888071eb6e00 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x7bf/0x1dd0 security/integrity/ima/ima_main.c:260

but task is already holding lock:
ffff888029288460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:376

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#5){.+.+}-{0:0}:
       lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1812 [inline]
       sb_start_write+0x4f/0x1a0 include/linux/fs.h:1882
       mnt_want_write+0x3b/0x80 fs/namespace.c:376
       ovl_maybe_copy_up+0x117/0x180 fs/overlayfs/copy_up.c:1047
       ovl_open+0xa2/0x200 fs/overlayfs/file.c:149
       do_dentry_open+0x7cb/0x1020 fs/open.c:822
       vfs_open fs/open.c:945 [inline]
       dentry_open+0xc6/0x120 fs/open.c:961
       ima_calc_file_hash+0x156/0x1b90 security/integrity/ima/ima_crypto.c:557
       ima_collect_measurement+0x27d/0x510 security/integrity/ima/ima_api.c:254
       process_measurement+0x101d/0x1dd0 security/integrity/ima/ima_main.c:337
       ima_file_check+0xed/0x170 security/integrity/ima/ima_main.c:516
       do_open fs/namei.c:3428 [inline]
       path_openat+0x2917/0x3670 fs/namei.c:3559
       do_filp_open+0x277/0x4f0 fs/namei.c:3586
       do_sys_openat2+0x13b/0x500 fs/open.c:1200
       do_sys_open fs/open.c:1216 [inline]
       __do_sys_open fs/open.c:1224 [inline]
       __se_sys_open fs/open.c:1220 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1220
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (&iint->mutex){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3051 [inline]
       check_prevs_add kernel/locking/lockdep.c:3174 [inline]
       validate_chain+0x1dfb/0x8240 kernel/locking/lockdep.c:3789
       __lock_acquire+0x1382/0x2b00 kernel/locking/lockdep.c:5015
       lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625
       __mutex_lock_common+0x1df/0x2550 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:743
       process_measurement+0x7bf/0x1dd0 security/integrity/ima/ima_main.c:260
       ima_file_check+0xed/0x170 security/integrity/ima/ima_main.c:516
       do_open fs/namei.c:3428 [inline]
       path_openat+0x2917/0x3670 fs/namei.c:3559
       do_filp_open+0x277/0x4f0 fs/namei.c:3586
       do_sys_openat2+0x13b/0x500 fs/open.c:1200
       do_sys_open fs/open.c:1216 [inline]
       __do_sys_openat fs/open.c:1232 [inline]
       __se_sys_openat fs/open.c:1227 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1227
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
       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-executor453/8406:
 #0: ffff888029288460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:376

stack backtrace:
CPU: 1 PID: 8406 Comm: syz-executor453 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:105
 check_noncircular+0x2f9/0x3b0 kernel/locking/lockdep.c:2131
 check_prev_add kernel/locking/lockdep.c:3051 [inline]
 check_prevs_add kernel/locking/lockdep.c:3174 [inline]
 validate_chain+0x1dfb/0x8240 kernel/locking/lockdep.c:3789
 __lock_acquire+0x1382/0x2b00 kernel/locking/lockdep.c:5015
 lock_acquire+0x19f/0x4d0 kernel/locking/lockdep.c:5625
 __mutex_lock_common+0x1df/0x2550 kernel/locking/mutex.c:596
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:743
 process_measurement+0x7bf/0x1dd0 security/integrity/ima/ima_main.c:260
 ima_file_check+0xed/0x170 security/integrity/ima/ima_main.c:516
 do_open fs/namei.c:3428 [inline]
 path_openat+0x2917/0x3670 fs/namei.c:3559
 do_filp_open+0x277/0x4f0 fs/namei.c:3586
 do_sys_openat2+0x13b/0x500 fs/open.c:1200
 do_sys_open fs/open.c:1216 [inline]
 __do_sys_openat fs/open.c:1232 [inline]
 __se_sys_openat fs/open.c:1227 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1227
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x444cc9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 14 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:00007f64a670b2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000004ca400 RCX: 0000000000444cc9
RDX: 000000000000275a RSI: 00000000200001c0 RDI: 00000000ffffff9c
RBP: 000000000049a004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 69662f7375622f2e
R13: 79706f636174656d R14: 0079616c7265766f