WARNING: possible circular locking dependency detected
5.5.0-rc6-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.2/16798 is trying to acquire lock:
ffff888076ba2428 (sb_writers#4){.+.+}, at: sb_start_write include/linux/fs.h:1650 [inline]
ffff888076ba2428 (sb_writers#4){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:354

but task is already holding lock:
ffff8880248be4b8 (&iint->mutex){+.+.}, at: process_measurement+0x394/0x1850 security/integrity/ima/ima_main.c:249

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&iint->mutex){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:956 [inline]
       __mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
       process_measurement+0x394/0x1850 security/integrity/ima/ima_main.c:249
       ima_file_check+0xc5/0x110 security/integrity/ima/ima_main.c:442
       do_last fs/namei.c:3424 [inline]
       path_openat+0x1138/0x4500 fs/namei.c:3537
       do_filp_open+0x1a1/0x280 fs/namei.c:3567
       do_sys_open+0x3fe/0x5d0 fs/open.c:1097
       __do_sys_open fs/open.c:1115 [inline]
       __se_sys_open fs/open.c:1110 [inline]
       __x64_sys_open+0x7e/0xc0 fs/open.c:1110
       do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (sb_writers#4){.+.+}:
       check_prev_add kernel/locking/lockdep.c:2476 [inline]
       check_prevs_add kernel/locking/lockdep.c:2581 [inline]
       validate_chain kernel/locking/lockdep.c:2971 [inline]
       __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955
       lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
       percpu_down_read include/linux/percpu-rwsem.h:40 [inline]
       __sb_start_write+0x241/0x460 fs/super.c:1674
       sb_start_write include/linux/fs.h:1650 [inline]
       mnt_want_write+0x3f/0xc0 fs/namespace.c:354
       ovl_want_write+0x76/0xa0 fs/overlayfs/util.c:21
       ovl_maybe_copy_up+0x122/0x180 fs/overlayfs/copy_up.c:911
       ovl_open+0xb8/0x270 fs/overlayfs/file.c:121
       do_dentry_open+0x4e6/0x1380 fs/open.c:797
       vfs_open fs/open.c:914 [inline]
       dentry_open+0x132/0x1d0 fs/open.c:930
       ima_calc_file_hash+0x33f/0x570 security/integrity/ima/ima_crypto.c:431
       ima_collect_measurement+0x534/0x5f0 security/integrity/ima/ima_api.c:247
       process_measurement+0xd45/0x1850 security/integrity/ima/ima_main.c:326
       ima_file_check+0xc5/0x110 security/integrity/ima/ima_main.c:442
       do_last fs/namei.c:3424 [inline]
       path_openat+0x1138/0x4500 fs/namei.c:3537
       do_filp_open+0x1a1/0x280 fs/namei.c:3567
       do_sys_open+0x3fe/0x5d0 fs/open.c:1097
       __do_sys_open fs/open.c:1115 [inline]
       __se_sys_open fs/open.c:1110 [inline]
       __x64_sys_open+0x7e/0xc0 fs/open.c:1110
       do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&iint->mutex);
                               lock(sb_writers#4);
                               lock(&iint->mutex);
  lock(sb_writers#4);

 *** DEADLOCK ***

1 lock held by syz-executor.2/16798:
 #0: ffff8880248be4b8 (&iint->mutex){+.+.}, at: process_measurement+0x394/0x1850 security/integrity/ima/ima_main.c:249

stack backtrace:
CPU: 2 PID: 16798 Comm: syz-executor.2 Not tainted 5.5.0-rc6-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_circular_bug.isra.0.cold+0x163/0x172 kernel/locking/lockdep.c:1685
 check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1809
 check_prev_add kernel/locking/lockdep.c:2476 [inline]
 check_prevs_add kernel/locking/lockdep.c:2581 [inline]
 validate_chain kernel/locking/lockdep.c:2971 [inline]
 __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3955
 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
 percpu_down_read include/linux/percpu-rwsem.h:40 [inline]
 __sb_start_write+0x241/0x460 fs/super.c:1674
 sb_start_write include/linux/fs.h:1650 [inline]
 mnt_want_write+0x3f/0xc0 fs/namespace.c:354
 ovl_want_write+0x76/0xa0 fs/overlayfs/util.c:21
 ovl_maybe_copy_up+0x122/0x180 fs/overlayfs/copy_up.c:911
 ovl_open+0xb8/0x270 fs/overlayfs/file.c:121
 do_dentry_open+0x4e6/0x1380 fs/open.c:797
 vfs_open fs/open.c:914 [inline]
 dentry_open+0x132/0x1d0 fs/open.c:930
 ima_calc_file_hash+0x33f/0x570 security/integrity/ima/ima_crypto.c:431
 ima_collect_measurement+0x534/0x5f0 security/integrity/ima/ima_api.c:247
 process_measurement+0xd45/0x1850 security/integrity/ima/ima_main.c:326
 ima_file_check+0xc5/0x110 security/integrity/ima/ima_main.c:442
 do_last fs/namei.c:3424 [inline]
 path_openat+0x1138/0x4500 fs/namei.c:3537
 do_filp_open+0x1a1/0x280 fs/namei.c:3567
 do_sys_open+0x3fe/0x5d0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1110
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45afd9
Code: bd b1 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 8b b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb25602bc88 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000000000072bf00 RCX: 000000000045afd9
RDX: 0000000000000008 RSI: 0000000000040803 RDI: 0000000020000080
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb25602c6d4
R13: 00000000004af657 R14: 00000000006f4ee0 R15: 00000000ffffffff