Patch "perf lock contention: Fix compiler builtin detection" has been added to the 6.3-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    perf lock contention: Fix compiler builtin detection

to the 6.3-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-lock-contention-fix-compiler-builtin-detection.patch
and it can be found in the queue-6.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 8071f32dd806328908a39a1b40f9afd0eabecb59
Author: Ian Rogers <irogers@xxxxxxxxxx>
Date:   Tue Mar 7 16:30:20 2023 -0800

    perf lock contention: Fix compiler builtin detection
    
    [ Upstream commit 17535a33a9c1e4fb52f3db1d72a7ddbe4cea1a2e ]
    
    __has_builtin was passed the macro rather than the actual builtin
    feature. The builtin test isn't sufficient and a clang version test
    also needs to be performed.
    
    Fixes: 1bece1351c653c3d ("perf lock contention: Support old rw_semaphore type")
    Reviewed-by: Namhyung Kim <namhyung@xxxxxxxxxx>
    Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
    Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
    Cc: Ingo Molnar <mingo@xxxxxxxxxx>
    Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
    Cc: Mark Rutland <mark.rutland@xxxxxxx>
    Cc: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
    Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
    Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
    Cc: bpf@xxxxxxxxxxxxxxx
    Link: https://lore.kernel.org/r/20230308003020.3653271-1-irogers@xxxxxxxxxx
    Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c
index e6007eaeda1a6..141b36d13b19a 100644
--- a/tools/perf/util/bpf_skel/lock_contention.bpf.c
+++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c
@@ -182,7 +182,13 @@ static inline struct task_struct *get_lock_owner(__u64 lock, __u32 flags)
 		struct mutex *mutex = (void *)lock;
 		owner = BPF_CORE_READ(mutex, owner.counter);
 	} else if (flags == LCB_F_READ || flags == LCB_F_WRITE) {
-#if __has_builtin(bpf_core_type_matches)
+	/*
+	 * Support for the BPF_TYPE_MATCHES argument to the
+	 * __builtin_preserve_type_info builtin was added at some point during
+	 * development of clang 15 and it's what is needed for
+	 * bpf_core_type_matches.
+	 */
+#if __has_builtin(__builtin_preserve_type_info) && __clang_major__ >= 15
 		if (bpf_core_type_matches(struct rw_semaphore___old)) {
 			struct rw_semaphore___old *rwsem = (void *)lock;
 			owner = (unsigned long)BPF_CORE_READ(rwsem, owner);