KASAN: slab-out-of-bounds Write in gfs2_fill_super

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fb0155a0 Merge tag 'nfs-for-5.9-3' of git://git.linux-nfs...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13458c0f900000
kernel config: https://syzkaller.appspot.com/x/.config?x=adebb40048274f92
dashboard link: https://syzkaller.appspot.com/bug?extid=af90d47a37376844e731
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15c307d3900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1353d58d900000

Bisection is inconclusive: the issue happens on the oldest tested release.

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=106acbbb900000
final oops: https://syzkaller.appspot.com/x/report.txt?x=126acbbb900000
console output: https://syzkaller.appspot.com/x/log.txt?x=146acbbb900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+af90d4...@syzkaller.appspotmail.com

gfs2: fsid=loop0: Trying to join cluster "lock_nolock", "loop0"
gfs2: fsid=loop0: Now mounting FS...
==================================================================
BUG: KASAN: slab-out-of-bounds in gfs2_read_sb fs/gfs2/ops_fstype.c:342 [inline]
BUG: KASAN: slab-out-of-bounds in init_sb fs/gfs2/ops_fstype.c:479 [inline]
BUG: KASAN: slab-out-of-bounds in gfs2_fill_super+0x1db5/0x3fe0 fs/gfs2/ops_fstype.c:1096
Write of size 8 at addr ffff88809073d548 by task syz-executor940/6853

CPU: 1 PID: 6853 Comm: syz-executor940 Not tainted 5.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1d6/0x29e lib/dump_stack.c:118
print_address_description+0x66/0x620 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report+0x132/0x1d0 mm/kasan/report.c:530
gfs2_read_sb fs/gfs2/ops_fstype.c:342 [inline]
init_sb fs/gfs2/ops_fstype.c:479 [inline]
gfs2_fill_super+0x1db5/0x3fe0 fs/gfs2/ops_fstype.c:1096
get_tree_bdev+0x3e9/0x5f0 fs/super.c:1342
gfs2_get_tree+0x4c/0x1f0 fs/gfs2/ops_fstype.c:1201
vfs_get_tree+0x88/0x270 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x179d/0x29e0 fs/namespace.c:3192
do_mount fs/namespace.c:3205 [inline]
__do_sys_mount fs/namespace.c:3413 [inline]
__se_sys_mount+0x126/0x180 fs/namespace.c:3390
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446dba
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007fff4c56e748 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff4c56e7a0 RCX: 0000000000446dba
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff4c56e760
RBP: 00007fff4c56e760 R08: 00007fff4c56e7a0 R09: 00007fff00000015
R10: 0000000002200000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

Allocated by task 6853:
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461
kmem_cache_alloc_trace+0x1e4/0x2e0 mm/slab.c:3554
kmalloc include/linux/slab.h:554 [inline]
kzalloc include/linux/slab.h:666 [inline]
init_sbd fs/gfs2/ops_fstype.c:77 [inline]
gfs2_fill_super+0xb6/0x3fe0 fs/gfs2/ops_fstype.c:1018
get_tree_bdev+0x3e9/0x5f0 fs/super.c:1342
gfs2_get_tree+0x4c/0x1f0 fs/gfs2/ops_fstype.c:1201
vfs_get_tree+0x88/0x270 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x179d/0x29e0 fs/namespace.c:3192
do_mount fs/namespace.c:3205 [inline]
__do_sys_mount fs/namespace.c:3413 [inline]
__se_sys_mount+0x126/0x180 fs/namespace.c:3390
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809073c000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 5448 bytes inside of
8192-byte region [ffff88809073c000, ffff88809073e000)
The buggy address belongs to the page:
page:00000000bd4b0b2d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9073c
head:00000000bd4b0b2d order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00028e5608 ffff8880aa441b50 ffff8880aa440a00
raw: 0000000000000000 ffff88809073c000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88809073d400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88809073d480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809073d500: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
^
ffff88809073d580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88809073d600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Andrew Price]

On 30/09/2020 13:39, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: fb0155a0 Merge tag 'nfs-for-5.9-3' of git://git.linux-nfs...
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=13458c0f900000
> kernel config: https://syzkaller.appspot.com/x/.config?x=adebb40048274f92
> dashboard link: https://syzkaller.appspot.com/bug?extid=af90d47a37376844e731
> compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15c307d3900000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1353d58d900000
>
> Bisection is inconclusive: the issue happens on the oldest tested release.
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=106acbbb900000
> final oops: https://syzkaller.appspot.com/x/report.txt?x=126acbbb900000
> console output: https://syzkaller.appspot.com/x/log.txt?x=146acbbb900000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+af90d4...@syzkaller.appspotmail.com
>
> gfs2: fsid=loop0: Trying to join cluster "lock_nolock", "loop0"
> gfs2: fsid=loop0: Now mounting FS...
> ==================================================================
> BUG: KASAN: slab-out-of-bounds in gfs2_read_sb fs/gfs2/ops_fstype.c:342 [inline]
> BUG: KASAN: slab-out-of-bounds in init_sb fs/gfs2/ops_fstype.c:479 [inline]
> BUG: KASAN: slab-out-of-bounds in gfs2_fill_super+0x1db5/0x3fe0 fs/gfs2/ops_fstype.c:1096
> Write of size 8 at addr ffff88809073d548 by task syz-executor940/6853

Bug filed for this:

https://bugzilla.redhat.com/show_bug.cgi?id=1883929

Andy

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-out-of-bounds Write in gfs2_fill_super

gfs2: fsid=loop3: Trying to join cluster "lock_nolock", "loop3"
gfs2: fsid=loop3: Now mounting FS...

==================================================================
BUG: KASAN: slab-out-of-bounds in gfs2_read_sb fs/gfs2/ops_fstype.c:342 [inline]
BUG: KASAN: slab-out-of-bounds in init_sb fs/gfs2/ops_fstype.c:479 [inline]
BUG: KASAN: slab-out-of-bounds in gfs2_fill_super+0x1db5/0x3fe0 fs/gfs2/ops_fstype.c:1096

Write of size 8 at addr ffff8880974a1548 by task syz-executor.3/8354

CPU: 1 PID: 8354 Comm: syz-executor.3 Not tainted 5.9.0-rc7-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1d6/0x29e lib/dump_stack.c:118
print_address_description+0x66/0x620 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report+0x132/0x1d0 mm/kasan/report.c:530
gfs2_read_sb fs/gfs2/ops_fstype.c:342 [inline]
init_sb fs/gfs2/ops_fstype.c:479 [inline]
gfs2_fill_super+0x1db5/0x3fe0 fs/gfs2/ops_fstype.c:1096
get_tree_bdev+0x3e9/0x5f0 fs/super.c:1342
gfs2_get_tree+0x4c/0x1f0 fs/gfs2/ops_fstype.c:1201
vfs_get_tree+0x88/0x270 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x179d/0x29e0 fs/namespace.c:3192
do_mount fs/namespace.c:3205 [inline]
__do_sys_mount fs/namespace.c:3413 [inline]
__se_sys_mount+0x126/0x180 fs/namespace.c:3390
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

RIP: 0033:0x4607ea
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 8a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f99d7241a88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f99d7241b20 RCX: 00000000004607ea
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f99d7241ae0
RBP: 00007f99d7241ae0 R08: 00007f99d7241b20 R09: 0000000020000000
R10: 0000000002200000 R11: 0000000000000246 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020000080

Allocated by task 8354:

kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461
kmem_cache_alloc_trace+0x1e4/0x2e0 mm/slab.c:3554
kmalloc include/linux/slab.h:554 [inline]
kzalloc include/linux/slab.h:666 [inline]
init_sbd fs/gfs2/ops_fstype.c:77 [inline]
gfs2_fill_super+0xb6/0x3fe0 fs/gfs2/ops_fstype.c:1018
get_tree_bdev+0x3e9/0x5f0 fs/super.c:1342
gfs2_get_tree+0x4c/0x1f0 fs/gfs2/ops_fstype.c:1201
vfs_get_tree+0x88/0x270 fs/super.c:1547
do_new_mount fs/namespace.c:2875 [inline]
path_mount+0x179d/0x29e0 fs/namespace.c:3192
do_mount fs/namespace.c:3205 [inline]
__do_sys_mount fs/namespace.c:3413 [inline]
__se_sys_mount+0x126/0x180 fs/namespace.c:3390
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880974a0000

which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 5448 bytes inside of

8192-byte region [ffff8880974a0000, ffff8880974a2000)

The buggy address belongs to the page:

page:00000000528f2f8a refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x974a0
head:00000000528f2f8a order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00025d6d08 ffff8880aa441b50 ffff8880aa440a00
raw: 0000000000000000 ffff8880974a0000 0000000100000001 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff8880974a1400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880974a1480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880974a1500: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc
^
ffff8880974a1580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880974a1600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit: 472e5b05 pipe: remove pipe_wait() and fix wakeup race with..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1445a4c7900000

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file fs/gfs2/ops_fstype.c
patch: **** unexpected end of file in patch



Tested on:

commit: fb0155a0 Merge tag 'nfs-for-5.9-3' of git://git.linux-nfs...

git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

dashboard link: https://syzkaller.appspot.com/bug?extid=af90d47a37376844e731
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)

patch: https://syzkaller.appspot.com/x/patch.diff?x=17930cc0500000

[Anant Thazhemadam]

Just saw this report.
This seems to be the same as
    https://syzkaller.appspot.com/bug?extid=a5e2482a693e6b1e444b ,
for which I have recently sent in a fix (https://lkml.org/lkml/2020/10/13/588).

Since the "Reported-by" tag in the patch sent is for the other instance of the
same crash, can we close this one as a duplicate?

Thanks,
Anant

[Andrew Price]

On 14/10/2020 13:19, Anant Thazhemadam wrote:
>
> On 30/09/20 7:52 pm, Andrew Price wrote:
>> On 30/09/2020 13:39, syzbot wrote:
>>> Hello,
>>>
>>> syzbot found the following issue on:
>>>
>>> HEAD commit:    fb0155a0 Merge tag 'nfs-for-5.9-3' of git://git.linux-nfs...
>>> git tree:       upstream
>>> console output: https://syzkaller.appspot.com/x/log.txt?x=13458c0f900000
>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=adebb40048274f92
>>> dashboard link: https://syzkaller.appspot.com/bug?extid=af90d47a37376844e731

>

> Just saw this report.
> This seems to be the same as
>     https://syzkaller.appspot.com/bug?extid=a5e2482a693e6b1e444b ,
> for which I have recently sent in a fix (https://lkml.org/lkml/2020/10/13/588).

Thanks. The gfs2 maintainers are probably busy but I'll review the patch.

> Since the "Reported-by" tag in the patch sent is for the other instance of the
> same crash, can we close this one as a duplicate?

I expect the duplicates will get closed once a fix is in the tree so
there's no need to spend time on that.

Andy

[Fox Chen]

Yes, it's the same bug,

https://lkml.org/lkml/2020/10/5/538 this may help


thanks,

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+af90d4...@syzkaller.appspotmail.com

Tested on:

commit: b5fc7a89 Merge tag 'overflow-v5.10-rc1' of git://git.kerne..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=4f0e58ab15d3b22b

dashboard link: https://syzkaller.appspot.com/bug?extid=af90d47a37376844e731
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)

patch: https://syzkaller.appspot.com/x/patch.diff?x=14ebae7f900000

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

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+af90d4...@syzkaller.appspotmail.com

Tested on:

commit: b5fc7a89 Merge tag 'overflow-v5.10-rc1' of git://git.kerne..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=4f0e58ab15d3b22b
dashboard link: https://syzkaller.appspot.com/bug?extid=af90d47a37376844e731
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)

patch: https://syzkaller.appspot.com/x/patch.diff?x=15194310500000

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+af90d4...@syzkaller.appspotmail.com

Tested on:

commit: b5fc7a89 Merge tag 'overflow-v5.10-rc1' of git://git.kerne..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=4f0e58ab15d3b22b
dashboard link: https://syzkaller.appspot.com/bug?extid=af90d47a37376844e731
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)

patch: https://syzkaller.appspot.com/x/patch.diff?x=11f7b05f900000