======================================================
WARNING: possible circular locking dependency detected
5.2.0-rc3-next-20190604 #8 Not tainted
------------------------------------------------------
syz-executor.2/1403 is trying to acquire lock:
00000000ded50df5 (&sb->s_type->i_mutex_key#10){++++}, at: inode_lock include/linux/fs.h:778 [inline]
00000000ded50df5 (&sb->s_type->i_mutex_key#10){++++}, at: process_measurement+0x15ae/0x15e0 security/integrity/ima/ima_main.c:228

but task is already holding lock:
00000000a10a6b4a (&mm->mmap_sem#2){++++}, at: do_mprotect_pkey+0x1f6/0xa30 mm/mprotect.c:485

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_sem#2){++++}:
       down_read+0x3f/0x1e0 kernel/locking/rwsem.c:24
       do_user_addr_fault arch/x86/mm/fault.c:1406 [inline]
       __do_page_fault+0x9e9/0xda0 arch/x86/mm/fault.c:1521
       do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1552
       page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1156
       fault_in_pages_readable include/linux/pagemap.h:600 [inline]
       iov_iter_fault_in_readable+0x377/0x450 lib/iov_iter.c:426
       generic_perform_write+0x186/0x520 mm/filemap.c:3197
       __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3336
       ext4_file_write_iter+0x332/0x1070 fs/ext4/file.c:266
       call_write_iter include/linux/fs.h:1870 [inline]
       new_sync_write+0x4d3/0x770 fs/read_write.c:483
       __vfs_write+0xe1/0x110 fs/read_write.c:496
       vfs_write+0x268/0x5d0 fs/read_write.c:558
       ksys_write+0x14f/0x290 fs/read_write.c:611
       __do_sys_write fs/read_write.c:623 [inline]
       __se_sys_write fs/read_write.c:620 [inline]
       __x64_sys_write+0x73/0xb0 fs/read_write.c:620
       do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (&sb->s_type->i_mutex_key#10){++++}:
       lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4300
       down_write+0x38/0xa0 kernel/locking/rwsem.c:66
       inode_lock include/linux/fs.h:778 [inline]
       process_measurement+0x15ae/0x15e0 security/integrity/ima/ima_main.c:228
       ima_file_mmap+0x11a/0x130 security/integrity/ima/ima_main.c:370
       security_file_mprotect+0xd5/0x100 security/security.c:1426
       do_mprotect_pkey+0x537/0xa30 mm/mprotect.c:550
       __do_sys_mprotect mm/mprotect.c:582 [inline]
       __se_sys_mprotect mm/mprotect.c:579 [inline]
       __x64_sys_mprotect+0x78/0xb0 mm/mprotect.c:579
       do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&mm->mmap_sem#2);
                               lock(&sb->s_type->i_mutex_key#10);
                               lock(&mm->mmap_sem#2);
  lock(&sb->s_type->i_mutex_key#10);

 *** DEADLOCK ***

1 lock held by syz-executor.2/1403:
 #0: 00000000a10a6b4a (&mm->mmap_sem#2){++++}, at: do_mprotect_pkey+0x1f6/0xa30 mm/mprotect.c:485

stack backtrace:
CPU: 1 PID: 1403 Comm: syz-executor.2 Not tainted 5.2.0-rc3-next-20190604 #8
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_circular_bug.cold+0x1cc/0x28f kernel/locking/lockdep.c:1566
 check_prev_add kernel/locking/lockdep.c:2311 [inline]
 check_prevs_add kernel/locking/lockdep.c:2419 [inline]
 validate_chain kernel/locking/lockdep.c:2801 [inline]
 __lock_acquire+0x3755/0x5490 kernel/locking/lockdep.c:3790
 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4300
 down_write+0x38/0xa0 kernel/locking/rwsem.c:66
 inode_lock include/linux/fs.h:778 [inline]
 process_measurement+0x15ae/0x15e0 security/integrity/ima/ima_main.c:228
 ima_file_mmap+0x11a/0x130 security/integrity/ima/ima_main.c:370
 security_file_mprotect+0xd5/0x100 security/security.c:1426
 do_mprotect_pkey+0x537/0xa30 mm/mprotect.c:550
 __do_sys_mprotect mm/mprotect.c:582 [inline]
 __se_sys_mprotect mm/mprotect.c:579 [inline]
 __x64_sys_mprotect+0x78/0xb0 mm/mprotect.c:579
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459279
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0667e8bc78 EFLAGS: 00000246 ORIG_RAX: 000000000000000a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459279
RDX: 0000000000000006 RSI: 0000000000800000 RDI: 0000000020000000
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0667e8c6d4
R13: 00000000004c5d11 R14: 00000000004d9670 R15: 00000000ffffffff