linux-kernel - Re: [PATCH] stacktrace: fix CONFIG_ARCH_STACKWALK stack_trace_save_tsk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190517191011.oe3g57vxwkf4gupa@treble>
Date:   Fri, 17 May 2019 14:10:11 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Joe Lawrence <joe.lawrence@...hat.com>
Cc:     live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
        jikos@...nel.org, pmladek@...e.com, tglx@...utronix.de
Subject: Re: [PATCH] stacktrace: fix CONFIG_ARCH_STACKWALK
 stack_trace_save_tsk_reliable return

On Fri, May 17, 2019 at 02:51:17PM -0400, Joe Lawrence wrote:
> Miroslav reported that the livepatch self-tests were failing,
> specifically a case in which the consistency model ensures that we do
> not patch a current executing function, "TEST: busy target module".
> 
> Recent renovations to stack_trace_save_tsk_reliable() left it returning
> only an -ERRNO success indication in some configuration combinations:
> 
>   klp_check_stack()
>     ret = stack_trace_save_tsk_reliable()
>       #ifdef CONFIG_ARCH_STACKWALK && CONFIG_HAVE_RELIABLE_STACKTRACE
>         stack_trace_save_tsk_reliable()
>           ret = arch_stack_walk_reliable()
>             return 0
>             return -EINVAL
>           ...
>           return ret;
>     ...
>     if (ret < 0)
>       /* stack_trace_save_tsk_reliable error */
>     nr_entries = ret;                               << 0
> 
> Previously (and currently for !CONFIG_ARCH_STACKWALK &&
> CONFIG_HAVE_RELIABLE_STACKTRACE) stack_trace_save_tsk_reliable()
> returned the number of entries that it consumed in the passed storage
> array.
> 
> In the case of the above config and trace, be sure to return the
> stacktrace_cookie.len on stack_trace_save_tsk_reliable() success.
> 
> Fixes: 25e39e32b0a3f ("livepatch: Simplify stack trace retrieval")
> Reported-by: Miroslav Benes <mbenes@...e.cz>
> Signed-off-by: Joe Lawrence <joe.lawrence@...hat.com>

It's great to see the livepatch selftests working and finding
regressions.

Acked-by: Josh Poimboeuf <jpoimboe@...hat.com>

-- 
Josh