======================================================
WARNING: possible circular locking dependency detected
5.13.0-rc2-next-20210518-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor269/8447 is trying to acquire lock:
ffff888018fe61a0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x3a8/0x17e0 security/integrity/ima/ima_main.c:253

but task is already holding lock:
ffff888147d38460 (sb_writers#5){.+.+}-{0:0}, at: do_open fs/namei.c:3354 [inline]
ffff888147d38460 (sb_writers#5){.+.+}-{0:0}, at: path_openat+0x1ad4/0x27d0 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:1763 [inline]
       sb_start_write include/linux/fs.h:1833 [inline]
       mnt_want_write+0x6e/0x3e0 fs/namespace.c:375
       ovl_maybe_copy_up+0x11f/0x190 fs/overlayfs/copy_up.c:996
       ovl_open+0xba/0x270 fs/overlayfs/file.c:149
       do_dentry_open+0x4b9/0x11c0 fs/open.c:826
       vfs_open fs/open.c:949 [inline]
       dentry_open+0x132/0x1d0 fs/open.c:965
       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+0xb1/0x100 security/integrity/ima/ima_main.c:499
       do_open fs/namei.c:3363 [inline]
       path_openat+0x15b0/0x27d0 fs/namei.c:3494
       do_filp_open+0x190/0x3d0 fs/namei.c:3521
       do_sys_openat2+0x16d/0x420 fs/open.c:1196
       do_sys_open fs/open.c:1212 [inline]
       __do_sys_open fs/open.c:1220 [inline]
       __se_sys_open fs/open.c:1216 [inline]
       __x64_sys_open+0x119/0x1c0 fs/open.c:1216
       do_syscall_64+0x31/0xb0 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+0xb1/0x100 security/integrity/ima/ima_main.c:499
       do_open fs/namei.c:3363 [inline]
       path_openat+0x15b0/0x27d0 fs/namei.c:3494
       do_filp_open+0x190/0x3d0 fs/namei.c:3521
       do_sys_openat2+0x16d/0x420 fs/open.c:1196
       do_sys_open fs/open.c:1212 [inline]
       __do_sys_openat fs/open.c:1228 [inline]
       __se_sys_openat fs/open.c:1223 [inline]
       __x64_sys_openat+0x13f/0x1f0 fs/open.c:1223
       do_syscall_64+0x31/0xb0 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-executor269/8447:
 #0: ffff888147d38460 (sb_writers#5){.+.+}-{0:0}, at: do_open fs/namei.c:3354 [inline]
 #0: ffff888147d38460 (sb_writers#5){.+.+}-{0:0}, at: path_openat+0x1ad4/0x27d0 fs/namei.c:3494

stack backtrace:
CPU: 1 PID: 8447 Comm: syz-executor269 Not tainted 5.13.0-rc2-next-20210518-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+0x13e/0x1d6 lib/dump_stack.c:129
 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+0xb1/0x100 security/integrity/ima/ima_main.c:499
 do_open fs/namei.c:3363 [inline]
 path_openat+0x15b0/0x27d0 fs/namei.c:3494
 do_filp_open+0x190/0x3d0 fs/namei.c:3521
 do_sys_openat2+0x16d/0x420 fs/open.c:1196
 do_sys_open fs/open.c:1212 [inline]
 __do_sys_openat fs/open.c:1228 [inline]
 __se_sys_openat fs/open.c:1223 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1223
 do_syscall_64+0x31/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x444d09
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:00007fef718eb2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000004ca400 RCX: 0000000000444d09
RDX: 000000000000275a RSI: 00000000200000c0 RDI: 00000000ffffff9c
RBP: 000000000049a004 R08: 0000000