[syzbot] possible deadlock in attr_data_get_block

[syzbot]

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=13ce2a7c880000
kernel config: https://syzkaller.appspot.com/x/.config?x=3a4a45d2d827c1e
dashboard link: https://syzkaller.appspot.com/bug?extid=36bb70085ef6edc2ebb9
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+36bb70...@syzkaller.appspotmail.com

ntfs3: loop4: Different NTFS' sector size (1024) and media sector size (512)
ntfs3: loop4: 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.4/15497 is trying to acquire lock:
ffff000116476948 (&ni->file.run_lock#3){++++}-{3:3}, at: attr_data_get_block+0x84/0xa54 fs/ntfs3/attrib.c:899

but task is already holding lock:
ffff0000c7543ad8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
ffff0000c7543ad8 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0xa0/0x1d0 mm/util.c:550

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock){++++}-{3:3}:
__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

-> #0 (&ni->file.run_lock#3){++++}-{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
down_read+0x5c/0x78 kernel/locking/rwsem.c:1499
attr_data_get_block+0x84/0xa54 fs/ntfs3/attrib.c:899
ntfs_file_mmap+0x1d0/0x2e4 fs/ntfs3/file.c:387
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

other info that might help us debug this:

Possible unsafe locking scenario:

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

*** DEADLOCK ***

1 lock held by syz-executor.4/15497:
#0: ffff0000c7543ad8 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff0000c7543ad8 (&mm->mmap_lock){++++}-{3:3}, at: vm_mmap_pgoff+0xa0/0x1d0 mm/util.c:550

stack backtrace:
CPU: 0 PID: 15497 Comm: syz-executor.4 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
down_read+0x5c/0x78 kernel/locking/rwsem.c:1499
attr_data_get_block+0x84/0xa54 fs/ntfs3/attrib.c:899
ntfs_file_mmap+0x1d0/0x2e4 fs/ntfs3/file.c:387
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


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: c2bf05db6c78 Merge tag 'i2c-for-6.1-rc8' of git://git.kern..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1090bfbd880000
kernel config: https://syzkaller.appspot.com/x/.config?x=2325e409a9a893e1

dashboard link: https://syzkaller.appspot.com/bug?extid=36bb70085ef6edc2ebb9
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1031c6cb880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15392bd5880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4476d2eff1ae/disk-c2bf05db.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0f4a704ffc14/vmlinux-c2bf05db.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dfb09481a98b/bzImage-c2bf05db.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/9b8a62d1948c/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+36bb70...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 4096

======================================================
WARNING: possible circular locking dependency detected

6.1.0-rc7-syzkaller-00200-gc2bf05db6c78 #0 Not tainted
------------------------------------------------------
syz-executor598/3631 is trying to acquire lock:
ffff888072430860 (&ni->ni_lock/4){+.+.}-{3:3}, at: ni_lock fs/ntfs3/ntfs_fs.h:1108 [inline]
ffff888072430860 (&ni->ni_lock/4){+.+.}-{3:3}, at: attr_data_get_block+0x301/0x2370 fs/ntfs3/attrib.c:917

but task is already holding lock:

ffff888022a38898 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
ffff888022a38898 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:518

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&mm->mmap_lock#2){++++}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__might_fault+0xb2/0x110 mm/memory.c:5645
_copy_to_user+0x26/0x130 lib/usercopy.c:29
copy_to_user include/linux/uaccess.h:169 [inline]
fiemap_fill_next_extent+0x22e/0x410 fs/ioctl.c:144
ni_fiemap+0xf57/0x1130 fs/ntfs3/frecord.c:1934
ntfs_fiemap+0x134/0x180 fs/ntfs3/file.c:1245
ioctl_fiemap fs/ioctl.c:219 [inline]
do_vfs_ioctl+0x187f/0x29a0 fs/ioctl.c:810
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&ni->ni_lock/4){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
ni_lock fs/ntfs3/ntfs_fs.h:1108 [inline]
attr_data_get_block+0x301/0x2370 fs/ntfs3/attrib.c:917
ntfs_file_mmap+0x48c/0x730 fs/ntfs3/file.c:387
call_mmap include/linux/fs.h:2204 [inline]
mmap_region+0xfe6/0x1e20 mm/mmap.c:2625
do_mmap+0x8d9/0xf30 mm/mmap.c:1412
vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:520
ksys_mmap_pgoff+0x48c/0x6d0 mm/mmap.c:1458
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----

lock(&mm->mmap_lock#2);
lock(&ni->ni_lock/4);
lock(&mm->mmap_lock#2);
lock(&ni->ni_lock/4);

*** DEADLOCK ***

1 lock held by syz-executor598/3631:
#0: ffff888022a38898 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff888022a38898 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:518

stack backtrace:
CPU: 1 PID: 3631 Comm: syz-executor598 Not tainted 6.1.0-rc7-syzkaller-00200-gc2bf05db6c78 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
ni_lock fs/ntfs3/ntfs_fs.h:1108 [inline]
attr_data_get_block+0x301/0x2370 fs/ntfs3/attrib.c:917
ntfs_file_mmap+0x48c/0x730 fs/ntfs3/file.c:387
call_mmap include/linux/fs.h:2204 [inline]
mmap_region+0xfe6/0x1e20 mm/mmap.c:2625
do_mmap+0x8d9/0xf30 mm/mmap.c:1412
vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:520
ksys_mmap_pgoff+0x48c/0x6d0 mm/mmap.c:1458
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f250307bcf9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:

[Hillf Danton]

On 04 Dec 2022 10:11:38 -0800

> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: c2bf05db6c78 Merge tag 'i2c-for-6.1-rc8' of git://git.kern..
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15392bd5880000

mmap fiemap
mmap_lock ni_lock
ni_lock run_lock
run_lock mmap_lock

To break the deadlock above, remove lock chains prior to mmap_lock in the
fiemap path.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git c2bf05db6c78

--- x/fs/ntfs3/file.c
+++ y/fs/ntfs3/file.c
@@ -1240,12 +1240,8 @@ int ntfs_fiemap(struct inode *inode, str
if (err)
return err;

- ni_lock(ni);
-
err = ni_fiemap(ni, fieinfo, start, len);

- ni_unlock(ni);
-
return err;
}

--- x/fs/ntfs3/frecord.c
+++ y/fs/ntfs3/frecord.c
@@ -1906,6 +1906,8 @@ int ni_fiemap(struct ntfs_inode *ni, str
u32 flags;
bool ok;

+ ni_lock(ni);
+
if (S_ISDIR(ni->vfs_inode.i_mode)) {
run = &ni->dir.alloc_run;
attr = ni_find_attr(ni, NULL, NULL, ATTR_ALLOC, I30_NAME,
@@ -1917,6 +1919,7 @@ int ni_fiemap(struct ntfs_inode *ni, str
NULL);
if (!attr) {
err = -EINVAL;
+ ni_unlock(ni);
goto out;
}
if (is_attr_compressed(attr)) {
@@ -1925,17 +1928,19 @@ int ni_fiemap(struct ntfs_inode *ni, str
ntfs_inode_warn(
&ni->vfs_inode,
"fiemap is not supported for compressed file (cp -r)");
+ ni_unlock(ni);
goto out;
}
run_lock = &ni->file.run_lock;
}

if (!attr || !attr->non_res) {
- err = fiemap_fill_next_extent(
- fieinfo, 0, 0,
- attr ? le32_to_cpu(attr->res.data_size) : 0,
- FIEMAP_EXTENT_DATA_INLINE | FIEMAP_EXTENT_LAST |
- FIEMAP_EXTENT_MERGED);
+ u64 sz = attr ? le32_to_cpu(attr->res.data_size) : 0;
+ ni_unlock(ni);
+ err = fiemap_fill_next_extent(fieinfo, 0, 0, sz,
+ FIEMAP_EXTENT_DATA_INLINE |
+ FIEMAP_EXTENT_LAST |
+ FIEMAP_EXTENT_MERGED);
goto out;
}

@@ -1945,6 +1950,7 @@ int ni_fiemap(struct ntfs_inode *ni, str
end = alloc_size;

down_read(run_lock);
+ ni_unlock(ni);

while (vbo < end) {
if (idx == -1) {
@@ -2027,8 +2033,10 @@ int ni_fiemap(struct ntfs_inode *ni, str
if (vbo + dlen >= end)
flags |= FIEMAP_EXTENT_LAST;

+ up_read(run_lock);
err = fiemap_fill_next_extent(fieinfo, vbo, lbo, dlen,
flags);
+ down_read(run_lock);
if (err < 0)
break;
if (err == 1) {
@@ -2048,7 +2056,9 @@ int ni_fiemap(struct ntfs_inode *ni, str
if (vbo + bytes >= end)
flags |= FIEMAP_EXTENT_LAST;

+ up_read(run_lock);
err = fiemap_fill_next_extent(fieinfo, vbo, lbo, bytes, flags);
+ down_read(run_lock);
if (err < 0)
break;
if (err == 1) {
--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+36bb70...@syzkaller.appspotmail.com

Tested on:

commit: c2bf05db Merge tag 'i2c-for-6.1-rc8' of git://git.kern..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10ac7d47880000

kernel config: https://syzkaller.appspot.com/x/.config?x=2325e409a9a893e1
dashboard link: https://syzkaller.appspot.com/bug?extid=36bb70085ef6edc2ebb9
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=14f9c10f880000

Note: testing is done by a robot and is best-effort only.