From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Kees Cook <keescook@chromium.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Next Mailing List <linux-next@vger.kernel.org>
Subject: Re: [PATCH] stacktrace: Provide stack_trace_save_tsk() stub in the !CONFIG_STACKTRACE case too
Date: Fri, 22 Oct 2021 13:38:35 +0200 [thread overview]
Message-ID: <YXKiu6U2aK//va1G@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YXJrtiFgwMCYNAAM@gmail.com>
On Fri, Oct 22, 2021 at 09:43:50AM +0200, Ingo Molnar wrote:
>
> * Qi Zheng <zhengqi.arch@bytedance.com> wrote:
>
> >
> >
> > On 10/18/21 2:23 PM, Stephen Rothwell wrote:
> > > Hi all,
> > >
> > > After merging the tip tree, today's linux-next build (x86_64 allnoconfig)
> > > failed like this:
> > >
> > > arch/x86/kernel/process.c: In function '__get_wchan':
> > > arch/x86/kernel/process.c:950:2: error: implicit declaration of function 'stack_trace_save_tsk' [-Werror=implicit-function-declaration]
> > > 950 | stack_trace_save_tsk(p, &entry, 1, 0);
> > > | ^~~~~~~~~~~~~~~~~~~~
> > > cc1: some warnings being treated as errors
> > >
> > > Caused by commit
> > >
> > > bc9bbb81730e ("x86: Fix get_wchan() to support the ORC unwinder")
> > >
> > > stack_trace_save_tsk() requires CONFIG_STACKTRACE which is not set for
> > > this build.
> >
> > Maybe get_wchan() can be updated to:
> >
> > unsigned long get_wchan(struct task_struct *p)
> > {
> > #ifdef CONFIG_STACKTRACE
> > unsigned long entry = 0;
> >
> > stack_trace_save_tsk(p, &entry, 1, 0);
> > return entry;
> > #else /* CONFIG_STACKTRACE */
> > return 0;
> > #endif
> > }
>
> And repeat the same ugliness in every single function that happens to use
> the stack_trace_save_tsk() API??
>
> The correct solution is to define stack_trace_save_tsk() in the
> !CONFIG_STACKTRACE case too, as the patch below does.
That doesn't make sense for x86. We have an unconditional unwinder
present.
I've got these, meant to post them later today:
https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=sched/wchan
prev parent reply other threads:[~2021-10-22 11:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-18 6:23 linux-next: build failure after merge of the tip tree Stephen Rothwell
2021-10-18 6:45 ` Qi Zheng
2021-10-22 7:43 ` [PATCH] stacktrace: Provide stack_trace_save_tsk() stub in the !CONFIG_STACKTRACE case too Ingo Molnar
2021-10-22 11:38 ` Peter Zijlstra [this message]
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