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From: Arnd Bergmann <arnd@arndb.de>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Denys Vlasenko <dvlasenk@redhat.com>
Subject: Re: [PATCH] objtool: fix another gcc jump table detection issue
Date: Fri, 3 Mar 2017 00:01:25 +0100	[thread overview]
Message-ID: <CAK8P3a1zOcKcHoKihaMp6_sjB2E36pq2pLZjPwjEgb_tuHzmLQ@mail.gmail.com> (raw)
In-Reply-To: <20170302225723.3ndbsnl4hkqbne7a@treble>

On Thu, Mar 2, 2017 at 11:57 PM, Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
> Arnd Bergmann reported a (false positive) objtool warning:
>
>   drivers/infiniband/sw/rxe/rxe_resp.o: warning: objtool: rxe_responder()+0xfe: sibling call from callable instruction with changed frame pointer
>
> The issue is in find_switch_table().  It tries to find a switch
> statement's jump table by walking backwards from an indirect jump
> instruction, looking for a relocation to the .rodata section.  In this
> case it stopped walking prematurely: the first .rodata relocation it
> encountered was for a variable (resp_state_name) instead of a jump
> table, so it just assumed there wasn't a jump table.
>
> The fix is to ignore any .rodata relocation which refers to an ELF
> object symbol.  This works because the jump tables are anonymous and
> have no symbols associated with them.
>
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: 3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>

Tested-by: Arnd Bergmann <arnd@arndb.de>

  reply	other threads:[~2017-03-02 23:02 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-10 12:56 [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann
2016-10-10 20:23 ` Josh Poimboeuf
2016-10-11  8:08   ` Arnd Bergmann
2016-10-11 12:20     ` Josh Poimboeuf
2016-10-11 13:30       ` Arnd Bergmann
2016-10-11 15:05         ` Josh Poimboeuf
2016-10-11 15:51           ` Josh Poimboeuf
2016-10-11 20:38             ` Arnd Bergmann
2016-10-12 13:01               ` Josh Poimboeuf
2016-10-13 12:46               ` Another gcc corruption bug (was Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings) Josh Poimboeuf
2016-10-13 17:57                 ` Denys Vlasenko
2016-10-13 20:15                   ` Josh Poimboeuf
2017-03-01  9:34               ` [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann
2017-03-01  9:45                 ` Arnd Bergmann
2017-03-01 14:40                   ` Josh Poimboeuf
2017-03-01 15:27                     ` Arnd Bergmann
2017-03-01 16:53                       ` Josh Poimboeuf
2017-03-01 22:05                         ` Arnd Bergmann
2017-03-01 22:42                         ` Arnd Bergmann
2017-03-02  1:03                           ` Josh Poimboeuf
2017-03-02  6:31                             ` Ingo Molnar
2017-03-02 12:49                               ` Josh Poimboeuf
2017-03-02 13:46                                 ` Ingo Molnar
2017-03-02 14:08                                   ` Josh Poimboeuf
2017-03-02 14:46                                     ` Ingo Molnar
2017-03-02 22:49                             ` Arnd Bergmann
2017-03-02 23:05                               ` Josh Poimboeuf
2017-03-03  8:58                                 ` Arnd Bergmann
2017-03-03 11:27                                   ` Arnd Bergmann
2017-03-01 14:31                 ` Josh Poimboeuf
2017-03-01 15:21                   ` Arnd Bergmann
2017-03-02 18:25                     ` Josh Poimboeuf
2017-03-02 22:43                       ` Arnd Bergmann
2017-03-02 22:57                         ` [PATCH] objtool: fix another gcc jump table detection issue Josh Poimboeuf
2017-03-02 23:01                           ` Arnd Bergmann [this message]
2016-10-11  1:53 ` [PATCH] objtool: support '-mtune=atom' stack frame setup instruction Josh Poimboeuf

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