syzbot


possible deadlock in __blockdev_direct_IO

Status: upstream: reported on 2024/11/11 18:12
Reported-by: syzbot+95be16803df9182b82e6@syzkaller.appspotmail.com
First crash: 39d, last: 33d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 possible deadlock in __blockdev_direct_IO (2) 3 9d11h 9d11h 0/3 upstream: reported on 2024/12/12 04:10
linux-6.1 possible deadlock in __blockdev_direct_IO 4 122d 129d 0/3 auto-obsoleted due to no activity on 2024/11/29 10:24

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.15.173-syzkaller #0 Not tainted
------------------------------------------------------
syz.6.793/7105 is trying to acquire lock:
ffff88802aa59d28 (&mm->mmap_lock){++++}-{3:3}, at: get_current arch/x86/include/asm/current.h:15 [inline]
ffff88802aa59d28 (&mm->mmap_lock){++++}-{3:3}, at: internal_get_user_pages_fast+0x1c7/0x2810 mm/gup.c:2895

but task is already holding lock:
ffff888061c503a0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
ffff888061c503a0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: do_blockdev_direct_IO fs/direct-io.c:1169 [inline]
ffff888061c503a0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: __blockdev_direct_IO+0x3db/0x4f40 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#21){+.+.}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_write+0x38/0x60 kernel/locking/rwsem.c:1551
       inode_lock include/linux/fs.h:789 [inline]
       ntfs_file_mmap+0x589/0x7e0 fs/ntfs3/file.c:401
       call_mmap include/linux/fs.h:2179 [inline]
       mmap_region+0x10e7/0x1670 mm/mmap.c:1791
       do_mmap+0x78d/0xe00 mm/mmap.c:1575
       vm_mmap_pgoff+0x1ca/0x2d0 mm/util.c:551
       ksys_mmap_pgoff+0x559/0x780 mm/mmap.c:1624
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 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+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       internal_get_user_pages_fast+0x212/0x2810 mm/gup.c:2895
       iov_iter_get_pages+0x25a/0x570 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+0x1419/0x4f40 fs/direct-io.c:1368
       blockdev_direct_IO include/linux/fs.h:3346 [inline]
       ntfs_direct_IO+0x193/0x360 fs/ntfs3/inode.c:798
       generic_file_read_iter+0x28d/0x460 mm/filemap.c:2772
       call_read_iter include/linux/fs.h:2168 [inline]
       new_sync_read fs/read_write.c:404 [inline]
       vfs_read+0xa93/0xe10 fs/read_write.c:485
       ksys_read+0x1a2/0x2c0 fs/read_write.c:623
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 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#21);
                               lock(
&mm->mmap_lock
);
                               lock(
&sb->s_type->i_mutex_key#21);
  lock(&mm->mmap_lock);

 *** DEADLOCK ***

2 locks held by syz.6.793/7105:
 #0: ffff888072d13c70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2cb/0x380 fs/file.c:1057
 #1: ffff888061c503a0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
 #1: ffff888061c503a0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: do_blockdev_direct_IO fs/direct-io.c:1169 [inline]
 #1: ffff888061c503a0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: __blockdev_direct_IO+0x3db/0x4f40 fs/direct-io.c:1368

stack backtrace:
CPU: 0 PID: 7105 Comm: syz.6.793 Not tainted 5.15.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 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+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 internal_get_user_pages_fast+0x212/0x2810 mm/gup.c:2895
 iov_iter_get_pages+0x25a/0x570 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+0x1419/0x4f40 fs/direct-io.c:1368
 blockdev_direct_IO include/linux/fs.h:3346 [inline]
 ntfs_direct_IO+0x193/0x360 fs/ntfs3/inode.c:798
 generic_file_read_iter+0x28d/0x460 mm/filemap.c:2772
 call_read_iter include/linux/fs.h:2168 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0xa93/0xe10 fs/read_write.c:485
 ksys_read+0x1a2/0x2c0 fs/read_write.c:623
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4bae8d6719
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:00007f4bacd4e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f4baea8df80 RCX: 00007f4bae8d6719
RDX: 0000000000002000 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f4bae94975e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4baea8df80 R15: 00007ffcd3784858
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/18 13:07 linux-5.15.y 0a51d2d4527b e7bb5d6e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in __blockdev_direct_IO
2024/11/18 13:07 linux-5.15.y 0a51d2d4527b e7bb5d6e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in __blockdev_direct_IO
2024/11/14 08:39 linux-5.15.y 3c17fc483905 a8c99394 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in __blockdev_direct_IO
2024/11/11 18:12 linux-5.15.y 3c17fc483905 0c4b1325 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan possible deadlock in __blockdev_direct_IO
* Struck through repros no longer work on HEAD.