syzbot

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.2.495/6020 is trying to acquire lock:
ffff888076fdb5d8 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0xa6/0x120 mm/memory.c:5852

but task is already holding lock:
ffff8880546ade48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline]
ffff8880546ade48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_dio_read_iter fs/ext4/file.c:78 [inline]
ffff8880546ade48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_file_read_iter+0x28f/0x650 fs/ext4/file.c:145

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#8){++++}-{3:3}:
       down_write+0x36/0x60 kernel/locking/rwsem.c:1573
       inode_lock include/linux/fs.h:758 [inline]
       process_measurement+0x33c/0x1a10 security/integrity/ima/ima_main.c:242
       ima_file_mmap+0x104/0x150 security/integrity/ima/ima_main.c:429
       __do_sys_remap_file_pages mm/mmap.c:3036 [inline]
       __se_sys_remap_file_pages+0x53e/0x770 mm/mmap.c:2968
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&mm->mmap_lock){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       __might_fault+0xc2/0x120 mm/memory.c:5852
       __clear_user arch/x86/include/asm/uaccess_64.h:96 [inline]
       clear_user arch/x86/include/asm/uaccess_64.h:124 [inline]
       iov_iter_zero+0x4d4/0x1280 lib/iov_iter.c:798
       iomap_dio_hole_iter fs/iomap/direct-io.c:390 [inline]
       iomap_dio_iter fs/iomap/direct-io.c:441 [inline]
       __iomap_dio_rw+0x12a6/0x1dd0 fs/iomap/direct-io.c:602
       iomap_dio_rw+0x41/0xa0 fs/iomap/direct-io.c:690
       ext4_dio_read_iter fs/ext4/file.c:94 [inline]
       ext4_file_read_iter+0x4ef/0x650 fs/ext4/file.c:145
       do_iter_readv_writev fs/read_write.c:-1 [inline]
       do_iter_read+0x63f/0xb10 fs/read_write.c:796
       vfs_readv fs/read_write.c:916 [inline]
       do_preadv+0x1f6/0x330 fs/read_write.c:1008
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sb->s_type->i_mutex_key#8);
                               lock(&mm->mmap_lock);
                               lock(&sb->s_type->i_mutex_key#8);
  lock(&mm->mmap_lock);

 *** DEADLOCK ***

1 lock held by syz.2.495/6020:
 #0: ffff8880546ade48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline]
 #0: ffff8880546ade48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_dio_read_iter fs/ext4/file.c:78 [inline]
 #0: ffff8880546ade48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_file_read_iter+0x28f/0x650 fs/ext4/file.c:145

stack backtrace:
CPU: 0 PID: 6020 Comm: syz.2.495 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __might_fault+0xc2/0x120 mm/memory.c:5852
 __clear_user arch/x86/include/asm/uaccess_64.h:96 [inline]
 clear_user arch/x86/include/asm/uaccess_64.h:124 [inline]
 iov_iter_zero+0x4d4/0x1280 lib/iov_iter.c:798
 iomap_dio_hole_iter fs/iomap/direct-io.c:390 [inline]
 iomap_dio_iter fs/iomap/direct-io.c:441 [inline]
 __iomap_dio_rw+0x12a6/0x1dd0 fs/iomap/direct-io.c:602
 iomap_dio_rw+0x41/0xa0 fs/iomap/direct-io.c:690
 ext4_dio_read_iter fs/ext4/file.c:94 [inline]
 ext4_file_read_iter+0x4ef/0x650 fs/ext4/file.c:145
 do_iter_readv_writev fs/read_write.c:-1 [inline]
 do_iter_read+0x63f/0xb10 fs/read_write.c:796
 vfs_readv fs/read_write.c:916 [inline]
 do_preadv+0x1f6/0x330 fs/read_write.c:1008
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fda1578ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fda1664d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007fda159c6090 RCX: 00007fda1578ebe9
RDX: 0000000000000001 RSI: 0000200000000400 RDI: 0000000000000004
RBP: 00007fda15811e19 R08: 0000000000000800 R09: 0000000000000000
R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fda159c6128 R14: 00007fda159c6090 R15: 00007ffc2ff448a8
 </TASK>