syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc3-syzkaller-00152-gf2f32f8af2b0 #0 Not tainted
------------------------------------------------------
syz-executor276/3616 is trying to acquire lock:
ffff88814bdf2460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393

but task is already holding lock:
ffff88801e13e1a0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x7ab/0x1bd0 security/integrity/ima/ima_main.c:260

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&iint->mutex){+.+.}-{3:3}:
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       __mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
       process_measurement+0x7ab/0x1bd0 security/integrity/ima/ima_main.c:260
       ima_file_check+0xd8/0x130 security/integrity/ima/ima_main.c:517
       do_open fs/namei.c:3559 [inline]
       path_openat+0x2642/0x2df0 fs/namei.c:3713
       do_filp_open+0x264/0x4f0 fs/namei.c:3740
       do_sys_openat2+0x124/0x4e0 fs/open.c:1310
       do_sys_open fs/open.c:1326 [inline]
       __do_sys_openat fs/open.c:1342 [inline]
       __se_sys_openat fs/open.c:1337 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1337
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/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:3097 [inline]
       check_prevs_add kernel/locking/lockdep.c:3216 [inline]
       validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
       __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
       lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1826 [inline]
       sb_start_write+0x4d/0x1a0 include/linux/fs.h:1901
       mnt_want_write+0x3b/0x80 fs/namespace.c:393
       ovl_maybe_copy_up+0x124/0x190 fs/overlayfs/copy_up.c:1083
       ovl_open+0xf3/0x290 fs/overlayfs/file.c:152
       do_dentry_open+0x85f/0x11b0 fs/open.c:882
       vfs_open fs/open.c:1013 [inline]
       dentry_open+0xc1/0x120 fs/open.c:1029
       ima_calc_file_hash+0x15b/0x1ca0 security/integrity/ima/ima_crypto.c:558
       ima_collect_measurement+0x444/0x8c0 security/integrity/ima/ima_api.c:292
       process_measurement+0xf4b/0x1bd0 security/integrity/ima/ima_main.c:337
       ima_file_check+0xd8/0x130 security/integrity/ima/ima_main.c:517
       do_open fs/namei.c:3559 [inline]
       path_openat+0x2642/0x2df0 fs/namei.c:3713
       do_filp_open+0x264/0x4f0 fs/namei.c:3740
       do_sys_openat2+0x124/0x4e0 fs/open.c:1310
       do_sys_open fs/open.c:1326 [inline]
       __do_sys_open fs/open.c:1334 [inline]
       __se_sys_open fs/open.c:1330 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1330
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/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);
  lock(sb_writers#4);

 *** DEADLOCK ***

1 lock held by syz-executor276/3616:
 #0: ffff88801e13e1a0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x7ab/0x1bd0 security/integrity/ima/ima_main.c:260

stack backtrace:
CPU: 0 PID: 3616 Comm: syz-executor276 Not tainted 6.1.0-rc3-syzkaller-00152-gf2f32f8af2b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
 check_prev_add kernel/locking/lockdep.c:3097 [inline]
 check_prevs_add kernel/locking/lockdep.c:3216 [inline]
 validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1826 [inline]
 sb_start_write+0x4d/0x1a0 include/linux/fs.h:1901
 mnt_want_write+0x3b/0x80 fs/namespace.c:393
 ovl_maybe_copy_up+0x124/0x190 fs/overlayfs/copy_up.c:1083
 ovl_open+0xf3/0x290 fs/overlayfs/file.c:152
 do_dentry_open+0x85f/0x11b0 fs/open.c:882
 vfs_open fs/open.c:1013 [inline]
 dentry_open+0xc1/0x120 fs/open.c:1029
 ima_calc_file_hash+0x15b/0x1ca0 security/integrity/ima/ima_crypto.c:558
 ima_collect_measurement+0x444/0x8c0 security/integrity/ima/ima_api.c:292
 process_measurement+0xf4b/0x1bd0 security/integrity/ima/ima_main.c:337
 ima_file_check+0xd8/0x130 security/integrity/ima/ima_main.c:517
 do_open fs/namei.c:3559 [inline]
 path_openat+0x2642/0x2df0 fs/namei.c:3713
 do_filp_open+0x264/0x4f0 fs/namei.c:3740
 do_sys_openat2+0x124/0x4e0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_open fs/open.c:1334 [inline]
 __se_sys_open fs/open.c:1330 [inline]
 __x64_sys_open+0x221/0x270 fs/open.c:1330
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f6067c69e29
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcfd5e2da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007f6067c69e29
RDX: 0000000000000000 RSI: 000000000000007f RDI: 0000000020000180
RBP: 0000000020000040 R08: 00007ffcfd5e2f48 R09: 00007ffcfd5e2f48
R10: 00007ffcfd5e2f48 R11: 0000000000000246 R12: 00007f6067c2d6b0
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
 </TASK>
syz-executor276 (3616) used greatest stack depth: 16088 bytes left