From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D61F83590C6; Fri, 9 Jan 2026 11:54:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767959692; cv=none; b=eea1L0QTbbbwSCuYW/i3zhTtjoRnOTMwkG7si/h7uOUWhb4YBMNJzZEQ8Le54R4hYJ9USpIa4LaJgAcN52QKjFC4VaEBOgQ4AwiaHR7fR1j4gak5HsuHalTrP/w/6UO/K3WMQX5gcPj2xrWJLcYYDi0wiaPylr8BHw65x/QwIGY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767959692; c=relaxed/simple; bh=BG4A6O3F3h9GPzKALFWDo+rwL54nDKPmcf20D2AO8MQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hwd+XgDNfxzinMlYsduQa/qzpe7FyDlAjRUd13kD0jKXbknutrmE7VuefSOtbbPG9zI461d0iAKTlHKixJb5zugMHvm+g2zRDlT/qMVACJ2fqxaRCzTvBz0TcQTusl2yFE5eAv+TxCPLinGeFgKCqSkj52ek98DFeqmfhziCm1o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=N3dFTH/Y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="N3dFTH/Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25725C4CEF1; Fri, 9 Jan 2026 11:54:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767959692; bh=BG4A6O3F3h9GPzKALFWDo+rwL54nDKPmcf20D2AO8MQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N3dFTH/Y3XVY2QJ0zMhvfEJWMVSynVw+HnC2yAlCZI9UgrRom0wpBT1GkyL2cLEgi NgR1rY6kY6pJt4KPJLuJ9U3o3w5xO10Y44Ah6LaP2F7s/0BsKS1F7i5GC1uNlKucQS Jm72kmofx6b5B76uHXaIOXsckQpXOJrRgBSf/VY4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Rogers , Adrian Hunter , Alexander Shishkin , Andi Kleen , Athira Rajeev , Changbin Du , Colin Ian King , Dmitrii Dolgov <9erthalion6@gmail.com>, German Gomez , Guilherme Amadio , Huacai Chen , Ingo Molnar , James Clark , Jiri Olsa , K Prateek Nayak , Kajol Jain , Kan Liang , Leo Yan , Li Dong , Liam Howlett , Mark Rutland , Masami Hiramatsu , Miguel Ojeda , Ming Wang , Namhyung Kim , Nick Terrell , Paolo Bonzini , Peter Zijlstra , Ravi Bangoria , Sandipan Das , Sean Christopherson , "Steinar H. Gunderson" , Vincent Whitchurch , Wenyu Liu , Yang Jihong , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 6.6 109/737] perf maps: Add maps__load_first() Date: Fri, 9 Jan 2026 12:34:08 +0100 Message-ID: <20260109112138.104073876@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112133.973195406@linuxfoundation.org> References: <20260109112133.973195406@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ian Rogers [ Upstream commit e77b0236cd0cd1572c6a9b25097b207eab799e74 ] Avoid bpf_lock_contention_read touching the internal maps data structure by adding a helper function. As access is done directly on the map in maps, hold the read lock to stop it being removed. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Athira Rajeev Cc: Changbin Du Cc: Colin Ian King Cc: Dmitrii Dolgov <9erthalion6@gmail.com> Cc: German Gomez Cc: Guilherme Amadio Cc: Huacai Chen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: K Prateek Nayak Cc: Kajol Jain Cc: Kan Liang Cc: Leo Yan Cc: Li Dong Cc: Liam Howlett Cc: Mark Rutland Cc: Masami Hiramatsu Cc: Miguel Ojeda Cc: Ming Wang Cc: Namhyung Kim Cc: Nick Terrell Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Cc: Sean Christopherson Cc: Steinar H. Gunderson Cc: Vincent Whitchurch Cc: Wenyu Liu Cc: Yang Jihong Link: https://lore.kernel.org/r/20231207011722.1220634-20-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo Stable-dep-of: 553d18c98a89 ("perf lock contention: Load kernel map before lookup") Signed-off-by: Sasha Levin --- tools/perf/util/bpf_lock_contention.c | 2 +- tools/perf/util/maps.c | 13 +++++++++++++ tools/perf/util/maps.h | 2 ++ 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c index e7dddf0127bce..a73f39540a3d4 100644 --- a/tools/perf/util/bpf_lock_contention.c +++ b/tools/perf/util/bpf_lock_contention.c @@ -285,7 +285,7 @@ int lock_contention_read(struct lock_contention *con) } /* make sure it loads the kernel map */ - map__load(maps__first(machine->kmaps)->map); + maps__load_first(machine->kmaps); prev_key = NULL; while (!bpf_map_get_next_key(fd, prev_key, &key)) { diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c index 9a011aed4b754..9c7618b7d5e92 100644 --- a/tools/perf/util/maps.c +++ b/tools/perf/util/maps.c @@ -713,3 +713,16 @@ int maps__merge_in(struct maps *kmaps, struct map *new_map) } return err; } + +void maps__load_first(struct maps *maps) +{ + struct map_rb_node *first; + + down_read(maps__lock(maps)); + + first = maps__first(maps); + if (first) + map__load(first->map); + + up_read(maps__lock(maps)); +} diff --git a/tools/perf/util/maps.h b/tools/perf/util/maps.h index a689149be8c43..d9f65f9e6d092 100644 --- a/tools/perf/util/maps.h +++ b/tools/perf/util/maps.h @@ -145,4 +145,6 @@ void __maps__sort_by_name(struct maps *maps); void maps__fixup_end(struct maps *maps); +void maps__load_first(struct maps *maps); + #endif // __PERF_MAPS_H -- 2.51.0