[syzbot] possible deadlock in ni_fiemap

syzbot
2022-10-18T05:47:36Z

Hello,

syzbot found the following issue on:

HEAD commit: bbed346d5a96 Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=131e9506880000
kernel config: https://syzkaller.appspot.com/x/.config?x=3a4a45d2d827c1e
dashboard link: https://syzkaller.appspot.com/bug?extid=c300ab283ba3bc072439
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e8e91bc79312/disk-bbed346d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c1cb3fb3b77e/vmlinux-bbed346d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c300ab283ba3bc072439@syzkaller.appspotmail.com

ntfs3: loop2: Different NTFS' sector size (1024) and media sector size (512)
ntfs3: loop2: Mark volume as dirty due to NTFS errors
======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0 Not tainted
------------------------------------------------------
syz-executor.2/17350 is trying to acquire lock:
ffff0000c79fb598 (&mm->mmap_lock){++++}-{3:3}, at: __might_fault+0x54/0xb4 mm/memory.c:5576

but task is already holding lock:
ffff000113418898 (&ni->file.run_lock#3){++++}-{3:3}, at: ni_fiemap+0x158/0x620 fs/ntfs3/frecord.c:1947

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ni->file.run_lock#3){++++}-{3:3}:
down_read+0x5c/0x78 kernel/locking/rwsem.c:1499
attr_data_get_block+0x84/0xa54 fs/ntfs3/attrib.c:899
ntfs_extend_initialized_size+0x108/0x334 fs/ntfs3/file.c:125
ntfs_file_mmap+0x290/0x2e4 fs/ntfs3/file.c:403
call_mmap include/linux/fs.h:2192 [inline]
mmap_region+0x7fc/0xc14 mm/mmap.c:1752
do_mmap+0x644/0x97c mm/mmap.c:1540
vm_mmap_pgoff+0xe8/0x1d0 mm/util.c:552
ksys_mmap_pgoff+0x1cc/0x278 mm/mmap.c:1586
__do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
__se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
__arm64_sys_mmap+0x58/0x6c arch/arm64/kernel/sys.c:21
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

-> #0 (&mm->mmap_lock){++++}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x1530/0x30a4 kernel/locking/lockdep.c:5053
lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5666
__might_fault+0x7c/0xb4 mm/memory.c:5577
_copy_to_user include/linux/uaccess.h:134 [inline]
copy_to_user include/linux/uaccess.h:160 [inline]
fiemap_fill_next_extent+0xc4/0x1f8 fs/ioctl.c:144
ni_fiemap+0x4cc/0x620 fs/ntfs3/frecord.c:2051
ntfs_fiemap+0x9c/0xdc fs/ntfs3/file.c:1245
ioctl_fiemap fs/ioctl.c:219 [inline]
do_vfs_ioctl+0x10f0/0x16a4 fs/ioctl.c:810
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x98/0x140 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ni->file.run_lock#3);
lock(&mm->mmap_lock);
lock(&ni->file.run_lock#3);
lock(&mm->mmap_lock);

*** DEADLOCK ***

2 locks held by syz-executor.2/17350:
#0: ffff0001134187e8 (&ni->ni_lock/4){+.+.}-{3:3}, at: ni_lock fs/ntfs3/ntfs_fs.h:1108 [inline]
#0: ffff0001134187e8 (&ni->ni_lock/4){+.+.}-{3:3}, at: ntfs_fiemap+0x88/0xdc fs/ntfs3/file.c:1243
#1: ffff000113418898 (&ni->file.run_lock#3){++++}-{3:3}, at: ni_fiemap+0x158/0x620 fs/ntfs3/frecord.c:1947

stack backtrace:
CPU: 1 PID: 17350 Comm: syz-executor.2 Not tainted 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
Call trace:
dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:156
show_stack+0x2c/0x54 arch/arm64/kernel/stacktrace.c:163
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x104/0x16c lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x2c4/0x2c8 kernel/locking/lockdep.c:2053
check_noncircular+0x14c/0x154 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x1530/0x30a4 kernel/locking/lockdep.c:5053
lock_acquire+0x100/0x1f8 kernel/locking/lockdep.c:5666
__might_fault+0x7c/0xb4 mm/memory.c:5577
_copy_to_user include/linux/uaccess.h:134 [inline]
copy_to_user include/linux/uaccess.h:160 [inline]
fiemap_fill_next_extent+0xc4/0x1f8 fs/ioctl.c:144
ni_fiemap+0x4cc/0x620 fs/ntfs3/frecord.c:2051
ntfs_fiemap+0x9c/0xdc fs/ntfs3/file.c:1245
ioctl_fiemap fs/ioctl.c:219 [inline]
do_vfs_ioctl+0x10f0/0x16a4 fs/ioctl.c:810
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x98/0x140 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x48/0x164 arch/arm64/kernel/syscall.c:206
el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:636
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:654
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

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