From: Miroslav Benes <mbenes@suse.cz>
To: Julien Thierry <jthierry@redhat.com>
Cc: linux-kernel@vger.kernel.org, jpoimboe@redhat.com,
peterz@infradead.org, raphael.gault@arm.com
Subject: Re: [PATCH v2 04/10] objtool: check: Ignore empty alternative groups
Date: Wed, 1 Apr 2020 14:53:42 +0200 (CEST) [thread overview]
Message-ID: <alpine.LSU.2.21.2004011450100.15809@pobox.suse.cz> (raw)
In-Reply-To: <20200327152847.15294-5-jthierry@redhat.com>
On Fri, 27 Mar 2020, Julien Thierry wrote:
> Atlernative section can contain entries for alternatives with no
> instructions. Objtool will currently crash when handling such an entry.
>
> Just skip that entry, but still give a warning to discourage useless
> entries.
>
> Signed-off-by: Julien Thierry <jthierry@redhat.com>
> ---
> tools/objtool/check.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index 74353b2c39ce..5c03460f1f07 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -904,6 +904,12 @@ static int add_special_section_alts(struct objtool_file *file)
> }
>
> if (special_alt->group) {
> + if (!special_alt->orig_len) {
> + WARN_FUNC("empty alternative entry",
> + orig_insn->sec, orig_insn->offset);
> + continue;
> + }
> +
> ret = handle_group_alt(file, special_alt, orig_insn,
> &new_insn);
> if (ret)
Probably the first time I am looking at alternatives handling in objtool,
so I must be missing something, but is this even possible now? I mean
get_alt_entry() in special.c sets alt->orig_len when alt->group is true
(which means .alternatives section) to something which cannot be zero.
Is this a preparatory patch for arm64, where this could happen? If yes, it
would be better to mention it in the changelog.
Miroslav
next prev parent reply other threads:[~2020-04-01 12:53 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 15:28 [PATCH v2 00/10] Objtool updates for easier portability Julien Thierry
2020-03-27 15:28 ` [PATCH v2 01/10] objtool: Move header sync-check ealier in build Julien Thierry
2020-04-01 12:32 ` Miroslav Benes
2020-04-01 12:44 ` Julien Thierry
2020-04-01 12:55 ` Miroslav Benes
2020-04-02 17:12 ` Josh Poimboeuf
2020-04-02 17:17 ` Josh Poimboeuf
2020-03-27 15:28 ` [PATCH v2 02/10] objtool: check: Remove redundant checks on operand type Julien Thierry
2020-03-27 15:28 ` [PATCH v2 03/10] objtool: check: Clean instruction state before each function validation Julien Thierry
2020-03-27 15:28 ` [PATCH v2 04/10] objtool: check: Ignore empty alternative groups Julien Thierry
2020-04-01 12:53 ` Miroslav Benes [this message]
2020-04-01 13:43 ` Julien Thierry
2020-04-01 13:48 ` Miroslav Benes
2020-03-27 15:28 ` [PATCH v2 05/10] objtool: check: Remove check preventing branches within alternative Julien Thierry
2020-05-01 18:22 ` [tip: objtool/core] objtool: " tip-bot2 for Julien Thierry
2020-03-27 15:28 ` [PATCH v2 06/10] objtool: check: Use arch specific values in restore_reg() Julien Thierry
2020-03-27 15:28 ` [PATCH v2 07/10] objtool: check: Allow save/restore hint in non standard function symbols Julien Thierry
2020-04-01 13:54 ` Miroslav Benes
2020-04-01 14:06 ` Julien Thierry
2020-03-27 15:28 ` [PATCH v2 08/10] objtool: Add abstraction for computation of symbols offsets Julien Thierry
2020-03-27 15:28 ` [PATCH v2 09/10] objtool: Split generic and arch specific CFI definitions Julien Thierry
2020-03-27 15:28 ` [PATCH v2 10/10] objtool: Support multiple stack_op per instruction Julien Thierry
2020-04-02 17:54 ` Josh Poimboeuf
2020-04-02 18:25 ` Peter Zijlstra
2020-04-03 8:01 ` Julien Thierry
2020-04-03 14:55 ` Josh Poimboeuf
2020-04-22 22:24 ` [tip: objtool/core] " tip-bot2 for Julien Thierry
2020-04-23 7:49 ` tip-bot2 for Julien Thierry
2020-04-23 11:15 ` Peter Zijlstra
2020-04-02 17:58 ` [PATCH v2 00/10] Objtool updates for easier portability Josh Poimboeuf
2020-04-02 18:30 ` Peter Zijlstra
2020-04-03 7:17 ` Miroslav Benes
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.LSU.2.21.2004011450100.15809@pobox.suse.cz \
--to=mbenes@suse.cz \
--cc=jpoimboe@redhat.com \
--cc=jthierry@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=raphael.gault@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).