syzbot

======================================================
WARNING: possible circular locking dependency detected
6.6.0-rc7-syzkaller-00195-g2af9b20dbb39 #0 Not tainted
------------------------------------------------------
syz-executor395/5029 is trying to acquire lock:
ffff88814c096410 (sb_writers#4){.+.+}-{0:0}, at: ovl_maybe_copy_up+0x121/0x180 fs/overlayfs/copy_up.c:1176

but task is already holding lock:
ffff8880167833e0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x893/0x1cc0 security/integrity/ima/ima_main.c:266

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&iint->mutex){+.+.}-{3:3}:
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x181/0x1340 kernel/locking/mutex.c:747
       process_measurement+0x893/0x1cc0 security/integrity/ima/ima_main.c:266
       ima_file_check+0xc2/0x110 security/integrity/ima/ima_main.c:543
       do_open fs/namei.c:3642 [inline]
       path_openat+0x17a1/0x29c0 fs/namei.c:3797
       do_filp_open+0x1de/0x430 fs/namei.c:3824
       do_sys_openat2+0x176/0x1e0 fs/open.c:1422
       do_sys_open fs/open.c:1437 [inline]
       __do_sys_openat fs/open.c:1453 [inline]
       __se_sys_openat fs/open.c:1448 [inline]
       __x64_sys_openat+0x175/0x210 fs/open.c:1448
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (sb_writers#4){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain kernel/locking/lockdep.c:3868 [inline]
       __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136
       lock_acquire kernel/locking/lockdep.c:5753 [inline]
       lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1571 [inline]
       sb_start_write include/linux/fs.h:1646 [inline]
       mnt_want_write+0x6f/0x440 fs/namespace.c:403
       ovl_maybe_copy_up+0x121/0x180 fs/overlayfs/copy_up.c:1176
       ovl_open+0x16f/0x330 fs/overlayfs/file.c:166
       do_dentry_open+0x88b/0x1730 fs/open.c:929
       vfs_open fs/open.c:1063 [inline]
       dentry_open+0x13f/0x1d0 fs/open.c:1079
       ima_calc_file_hash+0x2c4/0x4a0 security/integrity/ima/ima_crypto.c:558
       ima_collect_measurement+0x5e2/0x6f0 security/integrity/ima/ima_api.c:289
       process_measurement+0xc87/0x1cc0 security/integrity/ima/ima_main.c:345
       ima_file_check+0xc2/0x110 security/integrity/ima/ima_main.c:543
       do_open fs/namei.c:3642 [inline]
       path_openat+0x17a1/0x29c0 fs/namei.c:3797
       do_filp_open+0x1de/0x430 fs/namei.c:3824
       do_sys_openat2+0x176/0x1e0 fs/open.c:1422
       do_sys_open fs/open.c:1437 [inline]
       __do_sys_openat fs/open.c:1453 [inline]
       __se_sys_openat fs/open.c:1448 [inline]
       __x64_sys_openat+0x175/0x210 fs/open.c:1448
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by syz-executor395/5029:
 #0: ffff8880167833e0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x893/0x1cc0 security/integrity/ima/ima_main.c:266

stack backtrace:
CPU: 1 PID: 5029 Comm: syz-executor395 Not tainted 6.6.0-rc7-syzkaller-00195-g2af9b20dbb39 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 check_noncircular+0x311/0x3f0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain kernel/locking/lockdep.c:3868 [inline]
 __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136
 lock_acquire kernel/locking/lockdep.c:5753 [inline]
 lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1571 [inline]
 sb_start_write include/linux/fs.h:1646 [inline]
 mnt_want_write+0x6f/0x440 fs/namespace.c:403
 ovl_maybe_copy_up+0x121/0x180 fs/overlayfs/copy_up.c:1176
 ovl_open+0x16f/0x330 fs/overlayfs/file.c:166
 do_dentry_open+0x88b/0x1730 fs/open.c:929
 vfs_open fs/open.c:1063 [inline]
 dentry_open+0x13f/0x1d0 fs/open.c:1079
 ima_calc_file_hash+0x2c4/0x4a0 security/integrity/ima/ima_crypto.c:558
 ima_collect_measurement+0x5e2/0x6f0 security/integrity/ima/ima_api.c:289
 process_measurement+0xc87/0x1cc0 security/integrity/ima/ima_main.c:345
 ima_file_check+0xc2/0x110 security/integrity/ima/ima_main.c:543
 do_open fs/namei.c:3642 [inline]
 path_openat+0x17a1/0x29c0 fs/namei.c:3797
 do_filp_open+0x1de/0x430 fs/namei.c:3824
 do_sys_openat2+0x176/0x1e0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x175/0x210 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fc16aae9469
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 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:00007fff32799958 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007fc16aae9469
RDX: 0000000000000043 RSI: 00000000200000c0 RDI: 00000000ffffff