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Message-Id: <20251007225746.ad26cec6b6fa71b47033a7d7@kernel.org>
Date: Tue, 7 Oct 2025 22:57:46 +0900
From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
To: Menglong Dong <menglong.dong@...ux.dev>
Cc: Steven Rostedt <rostedt@...dmis.org>, Mark Brown <broonie@...nel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>, Menglong Dong
<menglong8.dong@...il.com>, Thorsten Blum <thorsten.blum@...ux.dev>,
linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org
Subject: Re: [for-next PATCH v2] tracing: wprobe: Fix to use IS_ERR_PCPU()
for per-cpu pointer
On Tue, 07 Oct 2025 11:12:18 +0800
Menglong Dong <menglong.dong@...ux.dev> wrote:
> On 2025/10/7 09:03, Masami Hiramatsu (Google) wrote:
> > From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
> >
> > Since wprobe uses IS_ERR() for per-cpu pointer, it failed to build.
> >
> > /tmp/next/build/kernel/trace/trace_wprobe.c: In function '__register_trace_wprobe':
> > /tmp/next/build/kernel/trace/trace_wprobe.c:176:20: error: cast to generic address space pointer from disjoint '__seg_gs' address space pointer [-Werror]
> > 176 | if (IS_ERR((void * __force)tw->bp_event)) {
> > | ^
> > /tmp/next/build/kernel/trace/trace_wprobe.c:177:35: error: cast to generic address space pointer from disjoint '__seg_gs' address space pointer [-Werror]
> > 177 | int ret = PTR_ERR((void * __force)tw->bp_event);
> > | ^
> >
> > Use IS_ERR_PCPU() instead.
> >
> > Reported-by: Mark Brown <broonie@...nel.org>
> > Closes: https://lore.kernel.org/all/aN6fTmAjD7-SJsw2@sirena.org.uk/
> > Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
> > ---
> > - Confirmed that `make allmodconfig && make` passed on x86_64 and arm64.
> > Changes in v2:
> > - Remove unneeded casting.
> > - Use PTR_ERR_PCPU() too.
> > ---
> > kernel/trace/trace_wprobe.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/trace/trace_wprobe.c b/kernel/trace/trace_wprobe.c
> > index 4b00a8e917c1..98605b207f43 100644
> > --- a/kernel/trace/trace_wprobe.c
> > +++ b/kernel/trace/trace_wprobe.c
> > @@ -173,8 +173,8 @@ static int __register_trace_wprobe(struct trace_wprobe *tw)
> > attr.bp_type = tw->type;
> >
> > tw->bp_event = register_wide_hw_breakpoint(&attr, wprobe_perf_handler, tw);
> > - if (IS_ERR((void * __force)tw->bp_event)) {
> > - int ret = PTR_ERR((void * __force)tw->bp_event);
> > + if (IS_ERR_PCPU(tw->bp_event)) {
> > + int ret = PTR_ERR_PCPU(tw->bp_event);
>
> This version LGTM.
>
> Reviewed-by: Menglong Dong <menglong8.dong@...il.com>
Thank you! Let me push it in probes/for-next.
>
> >
> > tw->bp_event = NULL;
> > return ret;
> >
> >
> >
>
>
>
>
--
Masami Hiramatsu (Google) <mhiramat@...nel.org>
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