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Subject: Re: memory leak in xskq_create
To:     Peilin Ye <yepeilin.cs@gmail.com>
Cc:     ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net,
        davem@davemloft.net, hawk@kernel.org, john.fastabend@gmail.com,
        jonathan.lemon@gmail.com, kuba@kernel.org,
        linux-kernel@vger.kernel.org, magnus.karlsson@intel.com,
        netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com
References: <0000000000002aca2e05b659af04@google.com>
 <20201216181135.GA94576@PWN>
From:   =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn.topel@intel.com>
Message-ID: <0a6cb67b-c24a-07e3-819b-820f3be9e3cd@intel.com>
Date:   Thu, 17 Dec 2020 08:12:26 +0100
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On 2020-12-16 19:11, Peilin Ye wrote:
> Hi all,
> 
> On Sun, Dec 13, 2020 at 06:53:10AM -0800, syzbot wrote:
>> BUG: memory leak
>> unreferenced object 0xffff88810f897940 (size 64):
>>    comm "syz-executor991", pid 8502, jiffies 4294942194 (age 14.080s)
>>    hex dump (first 32 bytes):
>>      7f 00 00 00 80 00 00 00 00 00 00 00 00 00 00 00  ................
>>      00 a0 37 0c 81 88 ff ff 00 00 00 00 00 00 00 00  ..7.............
>>    backtrace:
>>      [<00000000639d0dd1>] xskq_create+0x23/0xd0 include/linux/slab.h:552
>>      [<00000000b680b035>] xsk_init_queue net/xdp/xsk.c:508 [inline]
>>      [<00000000b680b035>] xsk_setsockopt+0x1c4/0x590 net/xdp/xsk.c:875
>>      [<000000002b302260>] __sys_setsockopt+0x1b0/0x360 net/socket.c:2132
>>      [<00000000ae03723e>] __do_sys_setsockopt net/socket.c:2143 [inline]
>>      [<00000000ae03723e>] __se_sys_setsockopt net/socket.c:2140 [inline]
>>      [<00000000ae03723e>] __x64_sys_setsockopt+0x22/0x30 net/socket.c:2140
>>      [<0000000005c2b4a0>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
>>      [<0000000003db140f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> 
> I have tested the following diff locally against syzbot's reproducer,
> and sent a patch to it [1] for testing.  I will send a real patch here
> tomorrow if syzbot is happy about it.  Please see explanation below.
>

Hi Peilin Ye!

Thanks for taking a look! Magnus has already addressed this problem in
another patch [1].


Cheers,
Björn


[1] 
https://lore.kernel.org/bpf/20201214085127.3960-1-magnus.karlsson@gmail.com/