Thread (3 messages) 3 messages, 2 authors, 2025-10-07

Re: [for-next PATCH v2] tracing: wprobe: Fix to use IS_ERR_PCPU() for per-cpu pointer

From: Menglong Dong <hidden>
Date: 2025-10-07 03:12:52
Also in: lkml

On 2025/10/7 09:03, Masami Hiramatsu (Google) wrote:
quoted hunk ↗ jump to hunk
From: Masami Hiramatsu (Google) <mhiramat@kernel.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@kernel.org>
Closes: https://lore.kernel.org/all/aN6fTmAjD7-SJsw2@sirena.org.uk/ (local)
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.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 <redacted>
 
 		tw->bp_event = NULL;
 		return ret;



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