On 01/20/2015 10:36 PM, Bruce Fields wrote:
> On Tue, Jan 20, 2015 at 08:26:58PM +0800, Junxiao Bi wrote:
>> On 01/20/2015 08:23 PM, Jeff Layton wrote:
>>> On Tue, 20 Jan 2015 19:49:47 +0800
>>> Junxiao Bi <junxiao.bi@xxxxxxxxxx> wrote:
>>>
>>>> On 01/19/2015 10:29 PM, Jeff Layton wrote:
>>>>> On Mon, 19 Jan 2015 09:17:51 +0800
>>>>> Junxiao Bi <junxiao.bi@xxxxxxxxxx> wrote:
>>>>>> Yes, we got the following panic from 3.8.13. The bad pointer
>>>>>> open->op_stp was freed into kmem_cache array_cache, and was allocated to
>>>>>> next "op_stp" allocation request which triggered the panic.
>>>>>>
>>>>>>
>>>>>> @ PID: 21663 TASK: ffff8809fe6103c0 CPU: 0 COMMAND: "nfsd"
>>>>>> @ #0 [ffff8809fe613980] machine_kexec at ffffffff810421d9
>>>>>> @ #1 [ffff8809fe6139f0] crash_kexec at ffffffff810c9d39
>>>>>> @ #2 [ffff8809fe613ac0] oops_end at ffffffff81599298
>>>>>> @ #3 [ffff8809fe613af0] die at ffffffff8101870b
>>>>>> @ #4 [ffff8809fe613b20] do_general_protection at ffffffff8159906c
>>>>>> @ #5 [ffff8809fe613b50] general_protection at ffffffff81598668
>>>>>> @ [exception RIP: init_stid+14]
>>>>>> @ RIP: ffffffffa058247e RSP: ffff8809fe613c08 RFLAGS: 00010292
>>>>>> @ RAX: 0000000000000000 RBX: 736e61727465722c RCX: 0000000000000000
>>>>>> @ RDX: 0000000000000001 RSI: ffff8808e433a800 RDI: 736e61727465722c
>>>>>> @ RBP: ffff8809fe613c28 R8: ffff880a01469000 R9: 0000000000000000
>>>>>> @ R10: 0000000000000000 R11: 0000000000000000 R12: ffff8808e19821a0
>>>>>> @ R13: ffff8809aa40f3a8 R14: ffff8809fd781040 R15: ffff8809aafc9c98
>>>>>> @ ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
>>>>>> @ #6 [ffff8809fe613c30] nfsd4_process_open2 at ffffffffa0588123 [nfsd]
>>>>>> @ #7 [ffff8809fe613d00] nfsd4_open at ffffffffa0577e82 [nfsd]
>>>>>> @ #8 [ffff8809fe613d50] nfsd4_proc_compound at ffffffffa0575de8 [nfsd]
>>>>>> @ #9 [ffff8809fe613db0] nfsd_dispatch at ffffffffa056429b [nfsd]
>>>>>> @ #10 [ffff8809fe613df0] svc_process_common at ffffffffa04afd14 [sunrpc]
>>>>>> @ #11 [ffff8809fe613e70] svc_process at ffffffffa04b034f [sunrpc]
>>>>>> @ #12 [ffff8809fe613e90] nfsd at ffffffffa05649ff [nfsd]
>>>>>> @ #13 [ffff8809fe613ec0] kthread at ffffffff81082f4e
>>>>>> @ #14 [ffff8809fe613f50] ret_from_fork at ffffffff815a09ac
> ...
>>>> Found the cause, this issue should have been fix by the following
>>>> commit. This fix is not merged in 3.8.13. Thanks for you and Trond
>>>> review it.
>
> Oh, sorry for not thinking of that one....
>
> I wonder how you hit this case--which client were you using?
Got this from customer, not sure how this is triggered. The client is
also using 3.8.13 kernel. The mount option is below
x:/xx /x/xx nfs4
rw,relatime,vers=4.0,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5p,clientaddr=x.x.x.x,local_lock=none,addr=x.x.x.x
0 0
Thanks,
Junxiao.
>
> --b.
>
>>>>
>>>> commit 5d6031ca742f9f07b9c9d9322538619f3bd155ac
>>>> Author: J. Bruce Fields <bfields@xxxxxxxxxx>
>>>> Date: Thu Jul 17 16:20:39 2014 -0400
>>>>
>>>> nfsd4: zero op arguments beyond the 8th compound op
>>>>
>>>> The first 8 ops of the compound are zeroed since they're a part of the
>>>> argument that's zeroed by the
>>>>
>>>> memset(rqstp->rq_argp, 0, procp->pc_argsize);
>>>>
>>>> in svc_process_common(). But we handle larger compounds by allocating
>>>> the memory on the fly in nfsd4_decode_compound(). Other than code
>>>> recently fixed by 01529e3f8179 "NFSD: Fix memory leak in encoding
>>>> denied
>>>> lock", I don't know of any examples of code depending on this
>>>> initialization. But it definitely seems possible, and I'd rather be
>>>> safe.
>>>>
>>>> Compounds this long are unusual so I'm much more worried about failure
>>>> in this poorly tested cases than about an insignificant performance
>>>> hit.
>>>>
>>>> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
>>>>
>>>> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
>>>> index 01023a5..628b430 100644
>>>> --- a/fs/nfsd/nfs4xdr.c
>>>> +++ b/fs/nfsd/nfs4xdr.c
>>>> @@ -1635,7 +1635,7 @@ nfsd4_decode_compound(struct nfsd4_compoundargs *argp)
>>>> goto xdr_error;
>>>>
>>>> if (argp->opcnt > ARRAY_SIZE(argp->iops)) {
>>>> - argp->ops = kmalloc(argp->opcnt * sizeof(*argp->ops),
>>>> GFP_KERNEL);
>>>> + argp->ops = kzalloc(argp->opcnt * sizeof(*argp->ops),
>>>> GFP_KERNEL);
>>>> if (!argp->ops) {
>>>> argp->ops = argp->iops;
>>>> dprintk("nfsd: couldn't allocate room for
>>>> COMPOUND\n");
>>>>
>>>> Thanks,
>>>> Junxiao.
>>> Yes, that patch looks fine, and I'm pretty sure it'd be ok for stable.
>> yes.
>>> I don't think v3.8 is being maintained anymore though, is it?
>> Used by us internal.
>>
>> Thanks,
>> Junxiao.
>>>
>>
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