general protection fault in integrity_inode_free

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 846e8dd47c26 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a59d56400000
kernel config: https://syzkaller.appspot.com/x/.config?x=dfb440e26f0a6f6f
dashboard link: https://syzkaller.appspot.com/bug?extid=4c0fa7d385ea5af34e91
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4c0fa7...@syzkaller.appspotmail.com

__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg net/socket.c:2161 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
entry_SYSCALL_64_after_hwframe+0x49/0xbe
general protection fault: 0000 [#1] PREEMPT SMP KASAN
RIP: 0033:0x457579
CPU: 0 PID: 8727 Comm: syz-executor3 Not tainted 4.19.0-rc5+ #33
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RSP: 002b:00007f07f2e4bc78 EFLAGS: 00000246
RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:168 [inline]
RIP: 0010:rb_erase+0x306/0x3710 lib/rbtree.c:459
ORIG_RAX: 000000000000002e
Code: c7 81 28 01 00 00 f2 f2 f2 f2 c7 81 2c 01 00 00 00 f2 f2 f2 48 89 f9
65 48 8b 1c 25 28 00 00 00 48 89 5d d0 31 db 48 c1 e9 03 <42> 80 3c 01 00
0f 85 41 1c 00 00 4c 8d 48 10 4c 8b 78 08 48 b9 00
RAX: ffffffffffffffda RBX: 00007f07f2e4bc90 RCX: 0000000000457579
RSP: 0018:ffff88018620e918 EFLAGS: 00010202
RDX: 0000000000000000 RSI: 000000002000b000 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f07f2e4c6d4
RDX: 1ffff10030c41d2b RSI: ffffffff8b5a08a0 RDI: 0000000000000008
R13: 00000000004c38e1 R14: 00000000004d5730 R15: 0000000000000004
RBP: ffff88018620f320 R08: dffffc0000000000 R09: fffffbfff135d5c8
kobject: 'loop5' (00000000eac6d22a): kobject_uevent_env
R10: fffffbfff135d5c8 R11: ffffffff89aeae43 R12: ffff8801bacb38f0
R13: dffffc0000000000 R14: ffff88018620f2f8 R15: ffff88018620f438
overlayfs: unrecognized mount option "smackfstransmute=upperdir" or missing
value
FS: 00007ff9677ec700(0000) GS:ffff8801dac00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31324000 CR3: 00000001c2773000 CR4: 00000000001406f0
Call Trace:
integrity_inode_free+0x12f/0x320 security/integrity/iint.c:150
security_inode_free+0x19/0x90 security/security.c:453
__destroy_inode+0x328/0x820 fs/inode.c:238
destroy_inode+0xda/0x200 fs/inode.c:265
evict+0x5e0/0x980 fs/inode.c:575
iput_final fs/inode.c:1547 [inline]
iput+0x679/0xa90 fs/inode.c:1573
swap_inode_boot_loader fs/ext4/ioctl.c:188 [inline]
ext4_ioctl+0x236f/0x4210 fs/ext4/ioctl.c:865
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:501 [inline]
do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
__do_sys_ioctl fs/ioctl.c:709 [inline]
__se_sys_ioctl fs/ioctl.c:707 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457579
Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff9677ebc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 0000000000457579
RDX: 0000000000000000 RSI: 0000000000006611 RDI: 0000000000000003
RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff9677ec6d4
R13: 00000000004bf626 R14: 00000000004cf4c0 R15: 00000000ffffffff
Modules linked in:
---[ end trace 6d41a32e43d56085 ]---
RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:168 [inline]
RIP: 0010:rb_erase+0x306/0x3710 lib/rbtree.c:459
Code: c7 81 28 01 00 00 f2 f2 f2 f2 c7 81 2c 01 00 00 00 f2 f2 f2 48 89 f9
65 48 8b 1c 25 28 00 00 00 48 89 5d d0 31 db 48 c1 e9 03 <42> 80 3c 01 00
0f 85 41 1c 00 00 4c 8d 48 10 4c 8b 78 08 48 b9 00
RSP: 0018:ffff88018620e918 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 1ffff10030c41d2b RSI: ffffffff8b5a08a0 RDI: 0000000000000008
RBP: ffff88018620f320 R08: dffffc0000000000 R09: fffffbfff135d5c8
R10: fffffbfff135d5c8 R11: ffffffff89aeae43 R12: ffff8801bacb38f0
R13: dffffc0000000000 R14: ffff88018620f2f8 R15: ffff88018620f438
FS: 00007ff9677ec700(0000) GS:ffff8801dac00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31324000 CR3: 00000001c2773000 CR4: 00000000001406f0


---
This bug is generated by a bot. It may contain errors.
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syzbot.

[Dmitry Vyukov]

On Wed, Sep 26, 2018 at 9:47 AM, syzbot
<syzbot+4c0fa7...@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 846e8dd47c26 Merge tag 'scsi-fixes' of git://git.kernel.or..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12a59d56400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=dfb440e26f0a6f6f
> dashboard link: https://syzkaller.appspot.com/bug?extid=4c0fa7d385ea5af34e91
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+4c0fa7...@syzkaller.appspotmail.com

This was misattributed to net, +IMA maintainers.

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[Dmitry Vyukov]

On Fri, Sep 28, 2018 at 9:44 PM, Mimi Zohar <zo...@linux.ibm.com> wrote:
> [Cc'ing Ignaz Forster and Fabian Vogt]
>
> Hi Dmitry,

>
> On Wed, 2018-09-26 at 09:53 +0200, Dmitry Vyukov wrote:
>> On Wed, Sep 26, 2018 at 9:47 AM, syzbot
>> <syzbot+4c0fa7...@syzkaller.appspotmail.com> wrote:
>> > Hello,
>> >
>> > syzbot found the following crash on:
>> >
>> > HEAD commit: 846e8dd47c26 Merge tag 'scsi-fixes' of git://git.kernel.or..
>> > git tree: upstream
>> > console output: https://syzkaller.appspot.com/x/log.txt?x=12a59d56400000
>> > kernel config: https://syzkaller.appspot.com/x/.config?x=dfb440e26f0a6f6f
>> > dashboard link: https://syzkaller.appspot.com/bug?extid=4c0fa7d385ea5af34e91
>> > compiler: gcc (GCC) 8.0.1 20180413 (experimental)
>> >
>> > Unfortunately, I don't have any reproducer for this crash yet.
>> >
>> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> > Reported-by: syzbot+4c0fa7...@syzkaller.appspotmail.com
>>
>> This was misattributed to net, +IMA maintainers.
>

> I'm wondering if this bug is somehow related to the other overlayfs
> issue, requiring the file to be opened O_RDWR to calculate the file
> hash. Could you pick up Ignaz and Fabian's temporary fix and retest?
>
> Sorry for taking this offline. Unfortunately, I'll be on vacation,
> again, Monday and Tuesday, without internet access. If that doesn't
> help, I'll look take a look when I get back.


Hi Mimi,

Testing with custom patches is unfortunately not possible on syzbot,
reasons for this are outlined here:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#no-custom-patches

except for patch testing for a particular bug with reproducer, which
is supported:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches

If this bug would have a reproducer, then we could submit the patch
for testing for this bug, and that would answer the question. However,
this bug looks quite hard to trigger as it happened only 3 times (some
elusive race?).

We can just wait till the patch is merged into upstream/linux-next and
then see if this crash still happened or not.

[Theodore Y. Ts'o]

On Wed, Sep 26, 2018 at 12:47:02AM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 846e8dd47c26 Merge tag 'scsi-fixes' of git://git.kernel.or..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=12a59d56400000
> kernel config: https://syzkaller.appspot.com/x/.config?x=dfb440e26f0a6f6f
> dashboard link: https://syzkaller.appspot.com/bug?extid=4c0fa7d385ea5af34e91
> compiler: gcc (GCC) 8.0.1 20180413 (experimental)

#syz dup: general protection fault in rb_erase