From: David Laight <David.Laight@ACULAB.COM>
To: "'Josh Poimboeuf'" <jpoimboe@redhat.com>,
"x86@kernel.org" <x86@kernel.org>
Cc: Andrey Konovalov <andreyknvl@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Vlad Yasevich <vyasevich@gmail.com>,
"Neil Horman" <nhorman@tuxdriver.com>,
"David S . Miller" <davem@davemloft.net>,
"linux-sctp@vger.kernel.org" <linux-sctp@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
"Kostya Serebryany" <kcc@google.com>,
syzkaller <syzkaller@googlegroups.com>,
"Eric Dumazet" <edumazet@google.com>,
Cong Wang <xiyou.wangcong@gmail.com>
Subject: RE: [PATCH] x86/asm: Don't use rbp as temp register in csum_partial_copy_generic()
Date: Thu, 4 May 2017 15:56:49 +0000 [thread overview]
Message-ID: <063D6719AE5E284EB5DD2968C1650D6DCFFE581C@AcuExch.aculab.com> (raw)
In-Reply-To: <4b03a961efda5ec9bfe46b7b9c9ad72d1efad343.1493909486.git.jpoimboe@redhat.com>
From: Josh Poimboeuf
> Sent: 04 May 2017 15:52
> Andrey Konovalov reported the following warning while fuzzing the kernel
> with syzkaller:
>
> WARNING: kernel stack regs at ffff8800686869f8 in a.out:4933 has bad 'bp' value c3fc855a10167ec0
>
> The unwinder dump revealed that rbp had a bad value when an interrupt
> occurred in csum_partial_copy_generic().
>
> That function saves rbp on the stack and then overwrites it, using it as
> a scratch register. That's problematic because it breaks stack traces
> if an interrupt occurs in the middle of the function.
Does gcc guarantee not to use bp as a scratch register in leaf functions?
David
next prev parent reply other threads:[~2017-05-04 15:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-04 14:51 [PATCH] x86/asm: Don't use rbp as temp register in csum_partial_copy_generic() Josh Poimboeuf
2017-05-04 15:56 ` David Laight [this message]
2017-05-04 16:11 ` Josh Poimboeuf
2017-05-05 8:10 ` [tip:x86/urgent] x86/asm: Don't use RBP as a temporary " tip-bot for Josh Poimboeuf
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