Re: [syzbot] [rdma?] KASAN: slab-use-after-free Read in siw_query_port

[syzbot]

>
>
> On 5/12/23 15:10, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit:    16a8829130ca nfs: fix another case of NULL/IS_ERR confusio..
>> git tree:       upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=162c0566280000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=8bc832f563d8bf38
>> dashboard link: https://syzkaller.appspot.com/bug?extid=79f283f1f4ccc6e8b624
>> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>>
>> Unfortunately, I don't have any reproducer for this issue yet.
>>
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/f8c18a31ba47/disk-16a88291.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/03a18f29b7e7/vmlinux-16a88291.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/1db2407ade1e/bzImage-16a88291.xz
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+79f283f1f4ccc6e8b624@xxxxxxxxxxxxxxxxxxxxxxxxx
>>
>> xfrm0 speed is unknown, defaulting to 1000
>> ==================================================================
>> BUG: KASAN: slab-use-after-free in siw_query_port+0x37b/0x3e0 drivers/infiniband/sw/siw/siw_verbs.c:177
>> Read of size 4 at addr ffff888034efa0e8 by task kworker/1:4/24211
>>
>> CPU: 1 PID: 24211 Comm: kworker/1:4 Not tainted 6.4.0-rc1-syzkaller-00012-g16a8829130ca #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
>> Workqueue: infiniband ib_cache_event_task
>> Call Trace:
>>   <TASK>
>>   __dump_stack lib/dump_stack.c:88 [inline]
>>   dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
>>   print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
>>   print_report mm/kasan/report.c:462 [inline]
>>   kasan_report+0x11c/0x130 mm/kasan/report.c:572
>>   siw_query_port+0x37b/0x3e0 drivers/infiniband/sw/siw/siw_verbs.c:177
>>   iw_query_port drivers/infiniband/core/device.c:2049 [inline]
>>   ib_query_port drivers/infiniband/core/device.c:2090 [inline]
>>   ib_query_port+0x3c4/0x8f0 drivers/infiniband/core/device.c:2082
>>   ib_cache_update.part.0+0xcf/0x920 drivers/infiniband/core/cache.c:1487
>>   ib_cache_update drivers/infiniband/core/cache.c:1561 [inline]
>>   ib_cache_event_task+0x1b1/0x270 drivers/infiniband/core/cache.c:1561
>>   process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
>>   worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552
>>   kthread+0x344/0x440 kernel/kthread.c:379
>>   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
>>   </TASK>
>
> This might be similar as 390d3fdcae2d,  let me play with syzbot a bit 😉
>
> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git 

This crash does not have a reproducer. I cannot test it.

> for-rc
>
> diff --git a/drivers/infiniband/core/device.c 
> b/drivers/infiniband/core/device.c
> index a666847bd714..9dd59f8d5f05 100644
> --- a/drivers/infiniband/core/device.c
> +++ b/drivers/infiniband/core/device.c
> @@ -2016,6 +2016,7 @@static int iw_query_port(struct ib_device *device,
> {
>         struct in_device *inetdev;
>         struct net_device *netdev;
> +int ret;
>
>         memset(port_attr, 0, sizeof(*port_attr));
>
> @@ -2045,8 +2046,9 @@static int iw_query_port(struct ib_device *device,
>                 rcu_read_unlock();
>         }
>
> +ret = device->ops.query_port(device, port_num, port_attr);
>         dev_put(netdev);
> -       return device->ops.query_port(device, port_num, port_attr);
> +return ret;
> }
>
> static int __ib_query_port(struct ib_device *device,