From nobody Mon Feb 9 13:00:54 2026 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 97C531531D8 for ; Mon, 4 Nov 2024 13:56:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730728617; cv=none; b=jxwSgbYOZBAxLQeRyYF+KNmw8v+npISlAGv0tHw4vKGwb52rQjAnNHAgSigGPV84mrKFmvqbNLWw3JJNsMxmYFMpbIZUPg9ZbHOPCmOLAR1tkbmjEgUYd6jlSzP/MUpjoDPMEnnD2WWKYiPAdOK7G8dIoSb5MgkWVRw0DYFRNj8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730728617; c=relaxed/simple; bh=FxeF8AnDf47O0S17Db3sOKWjCrmWnBgyQGNDgQvXEtg=; h=Message-Id:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=Hq9dOVy4aN+PhvuDlZ7uz/2vRz5VMonMbofWezIeTasUhMBiopB18LsCCYq3JAwuRjQiS5M6YtwPKCezusl8ZUX6osMr6nOzHS6uF0C0lCWCW1o10pdFPdVbya3THSR+JNJLnTgsa3jBBOPsWETIt2Xf4h+dTD0TCoLlr38jF1A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=DloN/mFQ; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="DloN/mFQ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=LHo/B2svVtNa82f3aNsJzufuQOwpLjpbG5fuvyX6S2c=; b=DloN/mFQ4/nPZqTFyn62jnqRCZ w5DuVFZdrOOGmAD61nL3Wf1kpS/sAP6GrVgu5YYyQX0YMOboFcxOkGkCr5U9fqpTmt4UIj2JVk1Ov f+2QsvOYLLqgk4RHCn5kA6U9fHOrTt9SN+7DNrL51sAwF7CceoMNDw3EzH+BS0qPH9Xc8Kw5uzlz6 RzO8JmiG8r4HfIl6t4W4nK2kCDt4WvLHPN9lYt2fXBAcXWXBSX+JPV1lbjJUDOybrexkPRzKG2/Vt hP6Mi+ri67iUDX3xUVkkPyJ0VolGNnH+AU6PNFzXtGfMTm1hsBiXeRlyO98jOOgsv6lNZckAtqaVd sV9hC+8g==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1t7xZY-00000001EE3-04w2; Mon, 04 Nov 2024 13:56:48 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 0) id 9FBDF308D9F; Mon, 4 Nov 2024 14:56:46 +0100 (CET) Message-Id: <20241104135519.582252957@infradead.org> User-Agent: quilt/0.65 Date: Mon, 04 Nov 2024 14:39:27 +0100 From: Peter Zijlstra To: mingo@kernel.org, lucas.demarchi@intel.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, willy@infradead.org, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com Subject: [PATCH 18/19] perf: Lift event->mmap_mutex in perf_mmap() References: <20241104133909.669111662@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This puts 'all' of perf_mmap() under single event->mmap_mutex. Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6626,7 +6626,7 @@ static int perf_mmap(struct file *file, unsigned long vma_size; unsigned long nr_pages; long user_extra =3D 0, extra =3D 0; - int ret =3D 0, flags =3D 0; + int ret, flags =3D 0; =20 /* * Don't allow mmap() of inherited per-task counters. This would @@ -6654,6 +6654,9 @@ static int perf_mmap(struct file *file, =20 user_extra =3D nr_pages; =20 + mutex_lock(&event->mmap_mutex); + ret =3D -EINVAL; + if (vma->vm_pgoff =3D=3D 0) { nr_pages -=3D 1; =20 @@ -6662,16 +6665,13 @@ static int perf_mmap(struct file *file, * can do bitmasks instead of modulo. */ if (nr_pages !=3D 0 && !is_power_of_2(nr_pages)) - return -EINVAL; + goto unlock; =20 WARN_ON_ONCE(event->ctx->parent_ctx); - mutex_lock(&event->mmap_mutex); =20 if (event->rb) { - if (data_page_nr(event->rb) !=3D nr_pages) { - ret =3D -EINVAL; + if (data_page_nr(event->rb) !=3D nr_pages) goto unlock; - } =20 if (atomic_inc_not_zero(&event->rb->mmap_count)) { /* @@ -6698,12 +6698,6 @@ static int perf_mmap(struct file *file, */ u64 aux_offset, aux_size; =20 - if (!event->rb) - return -EINVAL; - - mutex_lock(&event->mmap_mutex); - ret =3D -EINVAL; - rb =3D event->rb; if (!rb) goto aux_unlock; @@ -6813,6 +6807,8 @@ static int perf_mmap(struct file *file, rb->aux_mmap_locked =3D extra; } =20 + ret =3D 0; + unlock: if (!ret) { atomic_long_add(user_extra, &user->locked_vm);