[syzbot] WARNING in __v9fs_get_acl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 761c6d7ec820 Merge tag 'arc-5.14-rc6' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11d87ca1300000
kernel config: https://syzkaller.appspot.com/x/.config?x=730106bfb5bf8ace
dashboard link: https://syzkaller.appspot.com/bug?extid=56fdf7f6291d819b9b19
compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12ca6029300000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13bf42a1300000

The issue was bisected to:

commit 0ac1077e3a549bf8d35971613e2be05bdbb41a00
Author: Xin Long <lucie...@gmail.com>
Date: Tue Oct 16 07:52:02 2018 +0000

sctp: get pr_assoc and pr_stream all status with SCTP_PR_SCTP_ALL instead

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16f311fa300000
final oops: https://syzkaller.appspot.com/x/report.txt?x=15f311fa300000
console output: https://syzkaller.appspot.com/x/log.txt?x=11f311fa300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+56fdf7...@syzkaller.appspotmail.com
Fixes: 0ac1077e3a54 ("sctp: get pr_assoc and pr_stream all status with SCTP_PR_SCTP_ALL instead")

------------[ cut here ]------------
WARNING: CPU: 1 PID: 8426 at mm/page_alloc.c:5366 __alloc_pages+0x588/0x5f0 mm/page_alloc.c:5413
Modules linked in:
CPU: 1 PID: 8426 Comm: syz-executor477 Not tainted 5.14.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__alloc_pages+0x588/0x5f0 mm/page_alloc.c:5413
Code: 00 48 ba 00 00 00 00 00 fc ff df e9 5e fd ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 6d fd ff ff e8 bd 62 0a 00 e9 63 fd ff ff <0f> 0b 45 31 e4 e9 7a fd ff ff 48 8d 4c 24 50 80 e1 07 80 c1 03 38
RSP: 0018:ffffc90000fff9a0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000014 RCX: 0000000000000000
RDX: 0000000000000028 RSI: 0000000000000000 RDI: ffffc90000fffa28
RBP: ffffc90000fffaa8 R08: dffffc0000000000 R09: ffffc90000fffa00
R10: fffff520001fff45 R11: 0000000000000000 R12: 0000000000040d40
R13: ffffc90000fffa00 R14: 1ffff920001fff3c R15: 1ffff920001fff38
FS: 000000000148e300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa1e9a97740 CR3: 000000003406e000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
kmalloc_order+0x41/0x170 mm/slab_common.c:955
kmalloc_order_trace+0x15/0x70 mm/slab_common.c:971
kmalloc_large include/linux/slab.h:520 [inline]
__kmalloc+0x292/0x390 mm/slub.c:4101
kmalloc include/linux/slab.h:596 [inline]
kzalloc include/linux/slab.h:721 [inline]
__v9fs_get_acl+0x40/0x110 fs/9p/acl.c:36
v9fs_get_acl+0xa5/0x290 fs/9p/acl.c:71
v9fs_mount+0x6ea/0x870 fs/9p/vfs_super.c:182
legacy_get_tree+0xea/0x180 fs/fs_context.c:610
vfs_get_tree+0x86/0x270 fs/super.c:1498
do_new_mount fs/namespace.c:2919 [inline]
path_mount+0x196f/0x2be0 fs/namespace.c:3249
do_mount fs/namespace.c:3262 [inline]
__do_sys_mount fs/namespace.c:3470 [inline]
__se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3447
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+0x44/0xae
RIP: 0033:0x43f2e9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcc30ccf58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043f2e9
RDX: 0000000020000200 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 0000000000403040 R08: 0000000020004440 R09: 0000000000400488
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004030d0
R13: 0000000000000000 R14: 00000000004ad018 R15: 0000000000400488


---
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:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
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

[Pavel Skripkin]

Looks like syzbot tries to mount malicious image. Easy fix just for
thoughts:

diff --git a/fs/9p/acl.c b/fs/9p/acl.c
index bb1b286c49ae..242a3bc7aaee 100644
--- a/fs/9p/acl.c
+++ b/fs/9p/acl.c
@@ -33,7 +33,7 @@ static struct posix_acl *__v9fs_get_acl(struct p9_fid
*fid, char *name)

size = v9fs_fid_xattr_get(fid, name, NULL, 0);
if (size > 0) {
- value = kzalloc(size, GFP_NOFS);
+ value = kzalloc(size, GFP_NOFS | __GFP_NOWARN);
if (!value)
return ERR_PTR(-ENOMEM);
size = v9fs_fid_xattr_get(fid, name, value, size);




With regards,
Pavel Skripkin

[Xin Long]

On Mon, Aug 16, 2021 at 5:58 PM syzbot
<syzbot+56fdf7...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 761c6d7ec820 Merge tag 'arc-5.14-rc6' of git://git.kernel...
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11d87ca1300000
> kernel config: https://syzkaller.appspot.com/x/.config?x=730106bfb5bf8ace
> dashboard link: https://syzkaller.appspot.com/bug?extid=56fdf7f6291d819b9b19
> compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12ca6029300000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13bf42a1300000
>
> The issue was bisected to:
>
> commit 0ac1077e3a549bf8d35971613e2be05bdbb41a00
> Author: Xin Long <lucie...@gmail.com>
> Date: Tue Oct 16 07:52:02 2018 +0000
>
> sctp: get pr_assoc and pr_stream all status with SCTP_PR_SCTP_ALL instead

can't see how this is related.