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Message-ID: <CAAeHK+x_ka0XqQiAg5jrqQUSk2Ri0Ab-A62NTKYWj=i0TXQqZQ@mail.gmail.com>
Date: Wed, 3 May 2017 17:50:28 +0200
From: Andrey Konovalov <andreyknvl@...gle.com>
To: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
LKML <linux-kernel@...r.kernel.org>,
Vlad Yasevich <vyasevich@...il.com>,
Neil Horman <nhorman@...driver.com>,
"David S. Miller" <davem@...emloft.net>,
linux-sctp@...r.kernel.org, netdev <netdev@...r.kernel.org>,
Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Kostya Serebryany <kcc@...gle.com>,
syzkaller <syzkaller@...glegroups.com>,
Eric Dumazet <edumazet@...gle.com>,
Cong Wang <xiyou.wangcong@...il.com>
Subject: Re: x86: warning: kernel stack regs has bad 'bp' value
On Wed, May 3, 2017 at 3:30 PM, Josh Poimboeuf <jpoimboe@...hat.com> wrote:
> On Wed, May 03, 2017 at 02:48:28PM +0200, Andrey Konovalov wrote:
>> Hi,
>>
>> I've got the following error report while fuzzing the kernel with syzkaller.
>>
>> On commit 89c9fea3c8034cdb2fd745f551cde0b507fd6893 (4.11.0+).
>>
>> A reproducer and .config are attached.
>>
>> The reproducer open SCTP sockets and sends data to it in a loop.
>> I'm not sure whether this is an issue with SCTP or with something else.
>>
>> WARNING: kernel stack regs at ffff8800686869f8 in a.out:4933 has bad
>> 'bp' value c3fc855a10167ec0
>
> Hi Andrey,
>
> Can you test this patch?
Hi Josh,
This seems to be fixing the reports caused by the reproducers.
I'll keep fuzzing though with syzkaller to make sure.
Thanks!
>
>
> diff --git a/arch/x86/lib/csum-copy_64.S b/arch/x86/lib/csum-copy_64.S
> index 7e48807..45a53df 100644
> --- a/arch/x86/lib/csum-copy_64.S
> +++ b/arch/x86/lib/csum-copy_64.S
> @@ -55,7 +55,7 @@ ENTRY(csum_partial_copy_generic)
> movq %r12, 3*8(%rsp)
> movq %r14, 4*8(%rsp)
> movq %r13, 5*8(%rsp)
> - movq %rbp, 6*8(%rsp)
> + movq %r15, 6*8(%rsp)
>
> movq %r8, (%rsp)
> movq %r9, 1*8(%rsp)
> @@ -74,7 +74,7 @@ ENTRY(csum_partial_copy_generic)
> /* main loop. clear in 64 byte blocks */
> /* r9: zero, r8: temp2, rbx: temp1, rax: sum, rcx: saved length */
> /* r11: temp3, rdx: temp4, r12 loopcnt */
> - /* r10: temp5, rbp: temp6, r14 temp7, r13 temp8 */
> + /* r10: temp5, r15: temp6, r14 temp7, r13 temp8 */
> .p2align 4
> .Lloop:
> source
> @@ -89,7 +89,7 @@ ENTRY(csum_partial_copy_generic)
> source
> movq 32(%rdi), %r10
> source
> - movq 40(%rdi), %rbp
> + movq 40(%rdi), %r15
> source
> movq 48(%rdi), %r14
> source
> @@ -103,7 +103,7 @@ ENTRY(csum_partial_copy_generic)
> adcq %r11, %rax
> adcq %rdx, %rax
> adcq %r10, %rax
> - adcq %rbp, %rax
> + adcq %r15, %rax
> adcq %r14, %rax
> adcq %r13, %rax
>
> @@ -121,7 +121,7 @@ ENTRY(csum_partial_copy_generic)
> dest
> movq %r10, 32(%rsi)
> dest
> - movq %rbp, 40(%rsi)
> + movq %r15, 40(%rsi)
> dest
> movq %r14, 48(%rsi)
> dest
> @@ -203,7 +203,7 @@ ENTRY(csum_partial_copy_generic)
> movq 3*8(%rsp), %r12
> movq 4*8(%rsp), %r14
> movq 5*8(%rsp), %r13
> - movq 6*8(%rsp), %rbp
> + movq 6*8(%rsp), %r15
> addq $7*8, %rsp
> ret
>
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