syzbot

overlayfs: failed to resolve './bus': -2
======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc7-syzkaller-00220-gffb4d94b4314 #0 Not tainted
------------------------------------------------------
syz-executor134/3782 is trying to acquire lock:
ffff888075412980 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x3b9/0x18b0 security/integrity/ima/ima_main.c:260

but task is already holding lock:
ffff88807e864460 (sb_writers#4){.+.+}-{0:0}, at: do_open fs/namei.c:3550 [inline]
ffff88807e864460 (sb_writers#4){.+.+}-{0:0}, at: path_openat+0x1b5d/0x28f0 fs/namei.c:3691

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:1826 [inline]
       sb_start_write include/linux/fs.h:1901 [inline]
       mnt_want_write+0x6c/0x3e0 fs/namespace.c:393
       ovl_maybe_copy_up+0x11f/0x190 fs/overlayfs/copy_up.c:1077
       ovl_open+0xf1/0x2d0 fs/overlayfs/file.c:152
       do_dentry_open+0x4a4/0x13a0 fs/open.c:880
       vfs_open fs/open.c:1016 [inline]
       dentry_open+0x132/0x1d0 fs/open.c:1032
       ima_calc_file_hash+0x2c6/0x4a0 security/integrity/ima/ima_crypto.c:558
       ima_collect_measurement+0x5ca/0x710 security/integrity/ima/ima_api.c:292
       process_measurement+0xd1e/0x18b0 security/integrity/ima/ima_main.c:337
       ima_file_check+0xac/0x100 security/integrity/ima/ima_main.c:517
       do_open fs/namei.c:3559 [inline]
       path_openat+0x1611/0x28f0 fs/namei.c:3691
       do_filp_open+0x1b6/0x400 fs/namei.c:3718
       do_sys_openat2+0x16d/0x4c0 fs/open.c:1313
       do_sys_open fs/open.c:1329 [inline]
       __do_sys_openat fs/open.c:1345 [inline]
       __se_sys_openat fs/open.c:1340 [inline]
       __x64_sys_openat+0x13f/0x1f0 fs/open.c:1340
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 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:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain kernel/locking/lockdep.c:3829 [inline]
       __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
       lock_acquire kernel/locking/lockdep.c:5666 [inline]
       lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
       process_measurement+0x3b9/0x18b0 security/integrity/ima/ima_main.c:260
       ima_file_check+0xac/0x100 security/integrity/ima/ima_main.c:517
       do_open fs/namei.c:3559 [inline]
       path_openat+0x1611/0x28f0 fs/namei.c:3691
       do_filp_open+0x1b6/0x400 fs/namei.c:3718
       do_sys_openat2+0x16d/0x4c0 fs/open.c:1313
       do_sys_open fs/open.c:1329 [inline]
       __do_sys_open fs/open.c:1337 [inline]
       __se_sys_open fs/open.c:1333 [inline]
       __x64_sys_open+0x119/0x1c0 fs/open.c:1333
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x35/0xb0 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(sb_writers#4);
                               lock(&iint->mutex);
                               lock(sb_writers#4);
  lock(&iint->mutex);

 *** DEADLOCK ***

1 lock held by syz-executor134/3782:
 #0: ffff88807e864460 (sb_writers#4){.+.+}-{0:0}, at: do_open fs/namei.c:3550 [inline]
 #0: ffff88807e864460 (sb_writers#4){.+.+}-{0:0}, at: path_openat+0x1b5d/0x28f0 fs/namei.c:3691

stack backtrace:
CPU: 1 PID: 3782 Comm: syz-executor134 Not tainted 6.0.0-rc7-syzkaller-00220-gffb4d94b4314 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain kernel/locking/lockdep.c:3829 [inline]
 __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
 lock_acquire kernel/locking/lockdep.c:5666 [inline]
 lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x12f/0x1350 kernel/locking/mutex.c:747
 process_measurement+0x3b9/0x18b0 security/integrity/ima/ima_main.c:260
 ima_file_check+0xac/0x100 security/integrity/ima/ima_main.c:517
 do_open fs/namei.c:3559 [inline]
 path_openat+0x1611/0x28f0 fs/namei.c:3691
 do_filp_open+0x1b6/0x400 fs/namei.c:3718
 do_sys_openat2+0x16d/0x4c0 fs/open.c:1313
 do_sys_open fs/open.c:1329 [inline]
 __do_sys_open fs/open.c:1337 [inline]
 __se_sys_open fs/open.c:1333 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1333
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f045b274259
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 19 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:00007f045b1f8208 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f045b2fc258 RCX: 00007f045b274259
RDX: 0000000000000000 RSI: 0000000000080202 RDI: 0000000020000000
RBP: 00007f045b2fc250 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f045b2fc25c
R13: 00007ffcd674d2ff R14: 00007f045b1f8300 R15: 0000000000022000
 </TASK>