syzbot

loop2: detected capacity change from 0 to 4096
ntfs3: loop2: ino=21, "file1" fallocate(0x20) is not supported
======================================================
WARNING: possible circular locking dependency detected
5.15.189-syzkaller #0 Not tainted
------------------------------------------------------
syz.2.23/4462 is trying to acquire lock:
ffff88801e614728 (&mm->mmap_lock){++++}-{3:3}, at: get_current arch/x86/include/asm/current.h:15 [inline]
ffff88801e614728 (&mm->mmap_lock){++++}-{3:3}, at: internal_get_user_pages_fast+0x1af/0x2080 mm/gup.c:2895

but task is already holding lock:
ffff888074bba120 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff888074bba120 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: do_blockdev_direct_IO fs/direct-io.c:1169 [inline]
ffff888074bba120 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: __blockdev_direct_IO+0x391/0x3c90 fs/direct-io.c:1368

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}:
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       inode_lock include/linux/fs.h:787 [inline]
       ntfs_file_mmap+0x516/0x720 fs/ntfs3/file.c:401
       call_mmap include/linux/fs.h:2177 [inline]
       mmap_file+0x5d/0xb0 mm/util.c:1092
       __mmap_region mm/mmap.c:1792 [inline]
       mmap_region+0xd0d/0x15e0 mm/mmap.c:2929
       do_mmap+0x77a/0xdf0 mm/mmap.c:1582
       vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:551
       ksys_mmap_pgoff+0x542/0x780 mm/mmap.c:1631
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&mm->mmap_lock){++++}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
       lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
       internal_get_user_pages_fast+0x1fa/0x2080 mm/gup.c:2895
       iov_iter_get_pages+0x225/0x5b0 lib/iov_iter.c:1544
       dio_refill_pages fs/direct-io.c:173 [inline]
       dio_get_page fs/direct-io.c:217 [inline]
       do_direct_IO fs/direct-io.c:938 [inline]
       do_blockdev_direct_IO fs/direct-io.c:1276 [inline]
       __blockdev_direct_IO+0x1060/0x3c90 fs/direct-io.c:1368
       blockdev_direct_IO include/linux/fs.h:3344 [inline]
       ntfs_direct_IO+0x194/0x390 fs/ntfs3/inode.c:798
       generic_file_read_iter+0x2be/0x490 mm/filemap.c:2772
       call_read_iter include/linux/fs.h:2166 [inline]
       new_sync_read fs/read_write.c:404 [inline]
       vfs_read+0x725/0xcf0 fs/read_write.c:485
       ksys_read+0x14d/0x250 fs/read_write.c:623
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sb->s_type->i_mutex_key#26);
                               lock(&mm->mmap_lock);
                               lock(&sb->s_type->i_mutex_key#26);
  lock(&mm->mmap_lock);

 *** DEADLOCK ***

2 locks held by syz.2.23/4462:
 #0: ffff888076864af0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1058
 #1: ffff888074bba120 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff888074bba120 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: do_blockdev_direct_IO fs/direct-io.c:1169 [inline]
 #1: ffff888074bba120 (&sb->s_type->i_mutex_key#26){+.+.}-{3:3}, at: __blockdev_direct_IO+0x391/0x3c90 fs/direct-io.c:1368

stack backtrace:
CPU: 1 PID: 4462 Comm: syz.2.23 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 internal_get_user_pages_fast+0x1fa/0x2080 mm/gup.c:2895
 iov_iter_get_pages+0x225/0x5b0 lib/iov_iter.c:1544
 dio_refill_pages fs/direct-io.c:173 [inline]
 dio_get_page fs/direct-io.c:217 [inline]
 do_direct_IO fs/direct-io.c:938 [inline]
 do_blockdev_direct_IO fs/direct-io.c:1276 [inline]
 __blockdev_direct_IO+0x1060/0x3c90 fs/direct-io.c:1368
 blockdev_direct_IO include/linux/fs.h:3344 [inline]
 ntfs_direct_IO+0x194/0x390 fs/ntfs3/inode.c:798
 generic_file_read_iter+0x2be/0x490 mm/filemap.c:2772
 call_read_iter include/linux/fs.h:2166 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x725/0xcf0 fs/read_write.c:485
 ksys_read+0x14d/0x250 fs/read_write.c:623
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd480272be9
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:00007fd47e4da038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fd480499fa0 RCX: 00007fd480272be9
RDX: 0000000000001000 RSI: 0000200000001400 RDI: 0000000000000006
RBP: 00007fd4802f5e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd48049a038 R14: 00007fd480499fa0 R15: 00007ffe8eabb968
 </TASK>