[syzbot] general protection fault in smc_pnet_add (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d82a6c5ef9dc net: prestera: acl: make read-only array clie..
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13862081700000
kernel config: https://syzkaller.appspot.com/x/.config?x=cce8a73d5200f3c0
dashboard link: https://syzkaller.appspot.com/bug?extid=03e3e228510223dabd34
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=167da879700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12bb0fe1700000

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

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=11116ca1700000
final oops: https://syzkaller.appspot.com/x/report.txt?x=13116ca1700000
console output: https://syzkaller.appspot.com/x/log.txt?x=15116ca1700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+03e3e2...@syzkaller.appspotmail.com

infiniband syz: set active
infiniband syz: added veth0_vlan
RDS/IB: syz: added
smc: adding ib device syz with port count 1
smc: ib device syz port 1 has pnetid
general protection fault, probably for non-canonical address 0xdffffc000000000a: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000050-0x0000000000000057]
CPU: 1 PID: 3592 Comm: syz-executor235 Not tainted 5.17.0-rc6-syzkaller-01979-gd82a6c5ef9dc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:dev_name include/linux/device.h:636 [inline]
RIP: 0010:smc_pnet_find_ib net/smc/smc_pnet.c:314 [inline]
RIP: 0010:smc_pnet_add_ib net/smc/smc_pnet.c:416 [inline]
RIP: 0010:smc_pnet_enter net/smc/smc_pnet.c:515 [inline]
RIP: 0010:smc_pnet_add+0xc4b/0x17a0 net/smc/smc_pnet.c:558
Code: 8d be 58 07 00 00 48 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 40 09 00 00 4d 8b a6 58 07 00 00 49 8d 7c 24 50 48 89 f8 48 c1 e8 03 <80> 3c 28 00 0f 85 19 09 00 00 4d 8b 74 24 50 4d 85 f6 0f 85 21 ff
RSP: 0018:ffffc9000399f540 EFLAGS: 00010206
RAX: 000000000000000a RBX: ffff888076902800 RCX: 0000000000000000
RDX: ffff8880226f0000 RSI: ffffffff88cadba0 RDI: 0000000000000050
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffc9000399f47f
R10: ffffffff88cadb92 R11: 1ffffffff1eb5307 R12: 0000000000000000
R13: ffff88807066cc18 R14: ffff88801abc4000 R15: ffff888076902810
FS: 0000555555e61300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056492c9e2ff8 CR3: 0000000018900000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
netlink_unicast+0x539/0x7e0 net/netlink/af_netlink.c:1343
netlink_sendmsg+0x904/0xe00 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:725
____sys_sendmsg+0x6e8/0x810 net/socket.c:2413
___sys_sendmsg+0xf3/0x170 net/socket.c:2467
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2496
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f02fa3ae5d9
Code: 28 c3 e8 7a 15 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:00007ffd0d649788 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f02fa3ae5d9
RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000005
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000555555e612c0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dev_name include/linux/device.h:636 [inline]
RIP: 0010:smc_pnet_find_ib net/smc/smc_pnet.c:314 [inline]
RIP: 0010:smc_pnet_add_ib net/smc/smc_pnet.c:416 [inline]
RIP: 0010:smc_pnet_enter net/smc/smc_pnet.c:515 [inline]
RIP: 0010:smc_pnet_add+0xc4b/0x17a0 net/smc/smc_pnet.c:558
Code: 8d be 58 07 00 00 48 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 40 09 00 00 4d 8b a6 58 07 00 00 49 8d 7c 24 50 48 89 f8 48 c1 e8 03 <80> 3c 28 00 0f 85 19 09 00 00 4d 8b 74 24 50 4d 85 f6 0f 85 21 ff
RSP: 0018:ffffc9000399f540 EFLAGS: 00010206
RAX: 000000000000000a RBX: ffff888076902800 RCX: 0000000000000000
RDX: ffff8880226f0000 RSI: ffffffff88cadba0 RDI: 0000000000000050
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffc9000399f47f
R10: ffffffff88cadb92 R11: 1ffffffff1eb5307 R12: 0000000000000000
R13: ffff88807066cc18 R14: ffff88801abc4000 R15: ffff888076902810
FS: 0000555555e61300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056492c9f13a8 CR3: 0000000018900000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 8d be 58 07 00 00 lea 0x758(%rsi),%edi
6: 48 89 f8 mov %rdi,%rax
9: 48 c1 e8 03 shr $0x3,%rax
d: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1)
11: 0f 85 40 09 00 00 jne 0x957
17: 4d 8b a6 58 07 00 00 mov 0x758(%r14),%r12
1e: 49 8d 7c 24 50 lea 0x50(%r12),%rdi
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction
2e: 0f 85 19 09 00 00 jne 0x94d
34: 4d 8b 74 24 50 mov 0x50(%r12),%r14
39: 4d 85 f6 test %r14,%r14
3c: 0f .byte 0xf
3d: 85 21 test %esp,(%rcx)
3f: ff .byte 0xff


---
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.
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

[Karsten Graul]

On 31/03/2022 02:48, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: d82a6c5ef9dc net: prestera: acl: make read-only array clie..
> git tree: net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=13862081700000
> kernel config: https://syzkaller.appspot.com/x/.config?x=cce8a73d5200f3c0
> dashboard link: https://syzkaller.appspot.com/bug?extid=03e3e228510223dabd34
> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=167da879700000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12bb0fe1700000

dev.parent is not checked properly before dev_name() is called, I will provide a fix for this.

[Hillf Danton]

> On Wed, 30 Mar 2022 17:48:21 -0700

See if the parent pointer is stable.

Hillf

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/ d82a6c5ef9dc

--- y/net/smc/smc_pnet.c
+++ x/net/smc/smc_pnet.c
@@ -306,15 +306,20 @@ static bool smc_pnetid_valid(const char
static struct smc_ib_device *smc_pnet_find_ib(char *ib_name)
{
struct smc_ib_device *ibdev;
+ struct device *dev;

mutex_lock(&smc_ib_devices.mutex);
list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
- if (!strncmp(ibdev->ibdev->name, ib_name,
- sizeof(ibdev->ibdev->name)) ||
- !strncmp(dev_name(ibdev->ibdev->dev.parent), ib_name,
- IB_DEVICE_NAME_MAX - 1)) {
+ if (!strncmp(ibdev->ibdev->name, ib_name, sizeof(ibdev->ibdev->name)))
+ goto out;
+ dev = get_device(ibdev->ibdev->dev.parent);
+ if (!dev)
+ continue;
+ if (!strncmp(dev_name(dev), ib_name, IB_DEVICE_NAME_MAX - 1)) {
+ put_device(dev);
goto out;
}
+ put_device(dev);
}
ibdev = NULL;
out:
--

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+03e3e2...@syzkaller.appspotmail.com

Tested on:

commit: d82a6c5e net: prestera: acl: make read-only array clie..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/

kernel config: https://syzkaller.appspot.com/x/.config?x=cce8a73d5200f3c0
dashboard link: https://syzkaller.appspot.com/bug?extid=03e3e228510223dabd34
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

patch: https://syzkaller.appspot.com/x/patch.diff?x=17949c87700000

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