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From: Ingo Molnar <mingo@kernel.org>
To: Sathvika Vasireddy <sv@linux.ibm.com>
Cc: sfr@canb.auug.org.au, peterz@infradead.org,
	chenzhongjin@huawei.com, linux-kernel@vger.kernel.org,
	aik@ozlabs.ru, mingo@redhat.com, npiggin@gmail.com,
	jpoimboe@redhat.com, naveen.n.rao@linux.vnet.ibm.com,
	mbenes@suse.cz, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] objtool: continue if find_insn() fails in decode_instructions()
Date: Sat, 7 Jan 2023 11:21:39 +0100	[thread overview]
Message-ID: <Y7lHsw4diDgVc9ip@gmail.com> (raw)
In-Reply-To: <20221208072813.25799-1-sv@linux.ibm.com>


* Sathvika Vasireddy <sv@linux.ibm.com> wrote:

> Currently, decode_instructions() is failing if it is not able to find
> instruction, and this is happening since commit dbcdbdfdf137b4
> ("objtool: Rework instruction -> symbol mapping") because it is
> expecting instruction for STT_NOTYPE symbols.
> 
> Due to this, the following objtool warnings are seen:
>  [1] arch/powerpc/kernel/optprobes_head.o: warning: objtool: optprobe_template_end(): can't find starting instruction
>  [2] arch/powerpc/kernel/kvm_emul.o: warning: objtool: kvm_template_end(): can't find starting instruction
>  [3] arch/powerpc/kernel/head_64.o: warning: objtool: end_first_256B(): can't find starting instruction
> 
> The warnings are thrown because find_insn() is failing for symbols that
> are at the end of the file, or at the end of the section. Given how
> STT_NOTYPE symbols are currently handled in decode_instructions(),
> continue if the instruction is not found, instead of throwing warning
> and returning.
> 
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>

The SOB chain doesn't look valid: is Naveen N. Rao, the first SOB line, the 
author of the patch? If yes then a matching From: line is needed.

Or if two people developed the patch, then Co-developed-by should be used:

        Co-developed-by: First Co-Author <first@coauthor.example.org>
        Signed-off-by: First Co-Author <first@coauthor.example.org>
        Co-developed-by: Second Co-Author <second@coauthor.example.org>
        Signed-off-by: Second Co-Author <second@coauthor.example.org>

[ In this SOB sequence "Second Co-Author" is the one who submits the patch. ]

[ Please only use Co-developed-by if actual lines of code were written by 
  the co-author that created copyrightable material - it's not a courtesy 
  tag. Reviewed-by/Acked-by/Tested-by can be used to credit non-code 
  contributions. ]

Thanks,

	Ingo

WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@kernel.org>
To: Sathvika Vasireddy <sv@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	jpoimboe@redhat.com, peterz@infradead.org, aik@ozlabs.ru,
	mpe@ellerman.id.au, mingo@redhat.com,
	christophe.leroy@csgroup.eu, mbenes@suse.cz, npiggin@gmail.com,
	chenzhongjin@huawei.com, sfr@canb.auug.org.au,
	naveen.n.rao@linux.vnet.ibm.com
Subject: Re: [PATCH] objtool: continue if find_insn() fails in decode_instructions()
Date: Sat, 7 Jan 2023 11:21:39 +0100	[thread overview]
Message-ID: <Y7lHsw4diDgVc9ip@gmail.com> (raw)
In-Reply-To: <20221208072813.25799-1-sv@linux.ibm.com>


* Sathvika Vasireddy <sv@linux.ibm.com> wrote:

> Currently, decode_instructions() is failing if it is not able to find
> instruction, and this is happening since commit dbcdbdfdf137b4
> ("objtool: Rework instruction -> symbol mapping") because it is
> expecting instruction for STT_NOTYPE symbols.
> 
> Due to this, the following objtool warnings are seen:
>  [1] arch/powerpc/kernel/optprobes_head.o: warning: objtool: optprobe_template_end(): can't find starting instruction
>  [2] arch/powerpc/kernel/kvm_emul.o: warning: objtool: kvm_template_end(): can't find starting instruction
>  [3] arch/powerpc/kernel/head_64.o: warning: objtool: end_first_256B(): can't find starting instruction
> 
> The warnings are thrown because find_insn() is failing for symbols that
> are at the end of the file, or at the end of the section. Given how
> STT_NOTYPE symbols are currently handled in decode_instructions(),
> continue if the instruction is not found, instead of throwing warning
> and returning.
> 
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>

The SOB chain doesn't look valid: is Naveen N. Rao, the first SOB line, the 
author of the patch? If yes then a matching From: line is needed.

Or if two people developed the patch, then Co-developed-by should be used:

        Co-developed-by: First Co-Author <first@coauthor.example.org>
        Signed-off-by: First Co-Author <first@coauthor.example.org>
        Co-developed-by: Second Co-Author <second@coauthor.example.org>
        Signed-off-by: Second Co-Author <second@coauthor.example.org>

[ In this SOB sequence "Second Co-Author" is the one who submits the patch. ]

[ Please only use Co-developed-by if actual lines of code were written by 
  the co-author that created copyrightable material - it's not a courtesy 
  tag. Reviewed-by/Acked-by/Tested-by can be used to credit non-code 
  contributions. ]

Thanks,

	Ingo

  reply	other threads:[~2023-01-07 10:22 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-08  7:28 [PATCH] objtool: continue if find_insn() fails in decode_instructions() Sathvika Vasireddy
2022-12-08  7:28 ` Sathvika Vasireddy
2023-01-07 10:21 ` Ingo Molnar [this message]
2023-01-07 10:21   ` Ingo Molnar
2023-01-09 12:42   ` Sathvika Vasireddy
2023-01-09 12:42     ` Sathvika Vasireddy
2023-01-09 16:53     ` Ingo Molnar
2023-01-09 16:53       ` Ingo Molnar
2023-01-09 17:34       ` Sathvika Vasireddy
2023-01-09 17:34         ` Sathvika Vasireddy

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