[tip: perf/core] libbpf: Detect uprobe syscall with new error

[tip-bot2 for Jiri Olsa]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     c450c804b641003e0328e4b2ebf55c05f67e3d08
Gitweb:        https://git.kernel.org/tip/c450c804b641003e0328e4b2ebf55c05f67e3d08
Author:        Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate:    Fri, 03 Jul 2026 13:49:11 +02:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 03 Jul 2026 16:30:36 +02:00

libbpf: Detect uprobe syscall with new error

In the previous optimized uprobe fix we changed the syscall
error used for its detection from ENXIO to EPROTO.

Changing related probe_uprobe_syscall detection check.

Fixes: 05738da0efa1 ("libbpf: Add uprobe syscall feature detection")
Fixes: af734a7ddb4e ("uprobes/x86: Move optimized uprobe from nop5 to nop10")
Fixes: 40b54d7e3dab ("uprobes/x86: Move optimized uprobe from nop5 to nop10")
Fixes: 5c3c59c7952a ("uprobes/x86: Move optimized uprobe from nop5 to nop10")
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://patch.msgid.link/20260703114917.238144-8-jolsa@xxxxxxxxxx
---
 tools/lib/bpf/features.c                                | 4 ++--
 tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/features.c b/tools/lib/bpf/features.c
index b7e388f..e5641fa 100644
--- a/tools/lib/bpf/features.c
+++ b/tools/lib/bpf/features.c
@@ -577,10 +577,10 @@ static int probe_ldimm64_full_range_off(int token_fd)
 static int probe_uprobe_syscall(int token_fd)
 {
 	/*
-	 * If kernel supports uprobe() syscall, it will return -ENXIO when called
+	 * If kernel supports uprobe() syscall, it will return -EPROTO when called
 	 * from the outside of a kernel-generated uprobe trampoline.
 	 */
-	return syscall(__NR_uprobe) < 0 && errno == ENXIO;
+	return syscall(__NR_uprobe) < 0 && errno == EPROTO;
 }
 #else
 static int probe_uprobe_syscall(int token_fd)
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index 955a377..c944136 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -762,7 +762,7 @@ static void test_uprobe_error(void)
 	long err = syscall(__NR_uprobe);
 
 	ASSERT_EQ(err, -1, "error");
-	ASSERT_EQ(errno, ENXIO, "errno");
+	ASSERT_EQ(errno, EPROTO, "errno");
 }
 
 static void __test_uprobe_syscall(void)