syzbot

======================================================
WARNING: possible circular locking dependency detected
6.6.0-rc2-syzkaller-00018-g2cf0f7156238 #0 Not tainted
------------------------------------------------------
syz-executor284/5062 is trying to acquire lock:
ffff8880256a3e00 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x7c9/0x1cf0 security/integrity/ima/ima_main.c:266

but task is already holding lock:
ffff88814be9a410 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:403

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (sb_writers#4){.+.+}-{0:0}:
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1600 [inline]
       sb_start_write+0x4d/0x1c0 include/linux/fs.h:1675
       mnt_want_write+0x3f/0x90 fs/namespace.c:403
       ovl_maybe_copy_up+0x115/0x180 fs/overlayfs/copy_up.c:1176
       ovl_open+0x12b/0x310 fs/overlayfs/file.c:166
       do_dentry_open+0x80f/0x1430 fs/open.c:929
       vfs_open fs/open.c:1063 [inline]
       dentry_open+0xcb/0x120 fs/open.c:1079
       ima_calc_file_hash+0x166/0x1d20 security/integrity/ima/ima_crypto.c:558
       ima_collect_measurement+0x4a5/0x890 security/integrity/ima/ima_api.c:289
       process_measurement+0xfea/0x1cf0 security/integrity/ima/ima_main.c:345
       ima_file_check+0xf1/0x170 security/integrity/ima/ima_main.c:543
       do_open fs/namei.c:3641 [inline]
       path_openat+0x2812/0x3180 fs/namei.c:3796
       do_filp_open+0x234/0x490 fs/namei.c:3823
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1422
       do_sys_open fs/open.c:1437 [inline]
       __do_sys_open fs/open.c:1445 [inline]
       __se_sys_open fs/open.c:1441 [inline]
       __x64_sys_open+0x225/0x270 fs/open.c:1441
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&iint->mutex){+.+.}-{3:3}:
       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+0x39ff/0x7f70 kernel/locking/lockdep.c:5136
       lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x136/0xd60 kernel/locking/mutex.c:747
       process_measurement+0x7c9/0x1cf0 security/integrity/ima/ima_main.c:266
       ima_file_check+0xf1/0x170 security/integrity/ima/ima_main.c:543
       do_open fs/namei.c:3641 [inline]
       path_openat+0x2812/0x3180 fs/namei.c:3796
       do_filp_open+0x234/0x490 fs/namei.c:3823
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1422
       do_sys_open fs/open.c:1437 [inline]
       __do_sys_open fs/open.c:1445 [inline]
       __se_sys_open fs/open.c:1441 [inline]
       __x64_sys_open+0x225/0x270 fs/open.c:1441
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 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
       ----                    ----
  rlock(sb_writers#4);
                               lock(&iint->mutex);
                               lock(sb_writers#4);
  lock(&iint->mutex);

 *** DEADLOCK ***

1 lock held by syz-executor284/5062:
 #0: ffff88814be9a410 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:403

stack backtrace:
CPU: 1 PID: 5062 Comm: syz-executor284 Not tainted 6.6.0-rc2-syzkaller-00018-g2cf0f7156238 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x375/0x4a0 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+0x39ff/0x7f70 kernel/locking/lockdep.c:5136
 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x136/0xd60 kernel/locking/mutex.c:747
 process_measurement+0x7c9/0x1cf0 security/integrity/ima/ima_main.c:266
 ima_file_check+0xf1/0x170 security/integrity/ima/ima_main.c:543
 do_open fs/namei.c:3641 [inline]
 path_openat+0x2812/0x3180 fs/namei.c:3796
 do_filp_open+0x234/0x490 fs/namei.c:3823
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_open fs/open.c:1445 [inline]
 __se_sys_open fs/open.c:1441 [inline]
 __x64_sys_open+0x225/0x270 fs/open.c:1441
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9c9e5bdc89
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 18 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9c97159218 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f9c9e64b6b8 RCX: 00007f9c9e5bdc89
RDX: 0000000000000000 RSI: 000000000004c37e RDI: 0000000020000000
RBP: 00007f9c9e64b6b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9c9e617660
R13: 0031656c69662f2e R14: 6e6f3d7865646e69 R15: 0079616c7265766f
 </TASK>