From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC225525A6C for ; Mon, 7 Sep 2026 19:26:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788809211; cv=none; b=ZQrvlfomwmsxP5Zp4BJng0Ntz5nemfVb0q5hccJ9bUVM83UqB8PFA7h8xzank0LuW14EfYXQAgenL2Ql7V1riKdnSZ8b+ziW4q+QLsINGxsg/I4vYFwrkvJqv65vMnkY0odbU/yura2uM4Pk4kk+NnLBqUhRcrT/L/NWU855yyE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788809211; c=relaxed/simple; bh=VV2UYtfj14QiFFoEBe2SgvinoxBkc3CLTdw0RZkYt4A=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=CwFe5QRQCbPVs4OHU3Hdnyc7nFDeXjBZDI18zXdN7qjFrMwZjkNC3QcGMe3X9ErN/nnl9ObLhR1vfy0n9VRfYglECrSof1FvQ5MvhJBW/xefK+DkfL0brbJW3TLI7c7hkfvzQDzf3rzGNfU8xPSJBYXkLBhRYVMTX9maVHNHL5w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=JUuUwpRn; arc=none smtp.client-ip=209.85.128.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="JUuUwpRn" Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-49cdc4080ddso22289125e9.1 for ; Mon, 07 Sep 2026 12:26:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1788809207; x=1789414007; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=cOfeCPGjKhu5LNIU7QtSslcaAEx2w8+cq9M/aU9GG/0=; b=JUuUwpRnyvtvnhsicXI2LmAs/KYxwYoLDWO7P+B4s1yNxP5yX6GWvTLorTJM7vbgwB uVVuWQUjiB1/EgREhCtKRv2k9VVH6HOwB2JsP1TNcxSoNLmQWaq+vvQLaPznDbaHL1R2 nMQqmwaiAiRCUsgPCPnQyVp7Apx/Eoxd4NEGWB/v1A+O9VYYXKHzIFjUmNFiuTaZQrVF ax9vRCAKfsR0IPg7bEqPdlRrbkC73uvsvni+D2M8j+sW1VqVEV7HECIYqwVhGdmgRGcW exRbV0VSGDc3NGC4pNNCci8+fY8CK3n4okcRgn/gDeVmdtjpPyVa4uY/m0moWeXEE5UJ YgXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788809207; x=1789414007; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=cOfeCPGjKhu5LNIU7QtSslcaAEx2w8+cq9M/aU9GG/0=; b=cSExDuLfX/fplXHMr60x4m8T1tStbQCT5fPjeRiSrKcONfnO04MRRxQiZSQIwUqVVB SeDIMhGxPVFvjExVye9RdJzLKkIJIU89+eXhZezAaK2ZF1laEILpRr3Z79DyPxk1qwnW AYPDz7fSvHx98S+mZlkFOC7Px1G+rNq0eepPYWZiSzfLjBYnvGcFAuw4rnCUd76VT753 NmOF0ji3xmin6YDmIc3gRp+1f3lGNBkgs5mkppGTH6KhcWrgin9ZdVbREWocKAbFK1DQ qUCOI0M+ohtItq1NeuDDALdS4A6H36JZcshWOG97yzqw67y50cEVC4j+pMQP/VwOGCkH Ktqw== X-Forwarded-Encrypted: i=1; AKwUvBwtSP9mPJPWUikTXOr9uhkutxzvMTTsV9qhLT1NqYvaW9Z7wTJKSvDRtvVXc72+8se1XLtRmmXxi1j3+m4pOdG1jXE=@vger.kernel.org X-Gm-Message-State: AFuF++mx8gQEttP+xqbk8ihz/GhCh5LCze0GMhn3ap74iie1gdfBlH09 Ww88diWs+eHw+nUsfp152R/fZP+akkZGSqgKSCQ+ltwB7TCMBt/XXUH6e9AB0pbSDiFJPf/Qyll 1ys+IfZZh9gyMikwBZIRpUw== X-Received: from wmcu4.prod.google.com ([2002:a7b:c044:0:b0:490:b475:af08]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4fd6:b0:49b:4eb6:6ffd with SMTP id 5b1f17b1804b1-49d1754ecbfmr30403525e9.5.1788809206748; Mon, 07 Sep 2026 12:26:46 -0700 (PDT) Date: Mon, 7 Sep 2026 20:26:42 +0100 In-Reply-To: <20260907192643.42513-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260907192643.42513-1-vdonnefort@google.com> X-Mailer: git-send-email 2.55.0.979.g7e5102b832-goog Message-ID: <20260907192643.42513-2-vdonnefort@google.com> Subject: [PATCH v1 1/2] tracing/remotes: Account for ring buffer page header in size calculation From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, linux-trace-kernel@vger.kernel.org Cc: mathieu.desnoyers@efficios.com, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" trace_buffer_desc_size() and trace_remote_alloc_buffer undercount the required pages because every ring buffer page contains a header (BUF_PAGE_HDR_SIZE). Account for that header to ensure allocated remote ring buffers aren't smaller than requested by the user. While at it, ensure those functions catch nr_pages overflow. Fixes: 2e67fabd8b77 ("ring-buffer: Introduce ring-buffer remotes") Signed-off-by: Vincent Donnefort diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index afc7daa6ee7d..7a1a92f87650 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -8,6 +8,8 @@ #include +#include + struct trace_buffer; struct ring_buffer_iter; @@ -281,9 +283,14 @@ static inline struct ring_buffer_desc *__first_ring_buffer_desc(struct trace_buf static inline size_t trace_buffer_desc_size(size_t buffer_size, unsigned int nr_cpus) { - unsigned int nr_pages = max(DIV_ROUND_UP(buffer_size, PAGE_SIZE), 2UL) + 1; + unsigned long nr_pages = + max(DIV_ROUND_UP(buffer_size, PAGE_SIZE - BUF_PAGE_HDR_SIZE), 2UL) + 1; struct ring_buffer_desc *rbdesc; + /* Capped by ring_buffer_desc::nr_page_va */ + if (nr_pages > UINT_MAX) + return SIZE_MAX; + return size_add(offsetof(struct trace_buffer_desc, __data), size_mul(nr_cpus, struct_size(rbdesc, page_va, nr_pages))); } diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index 75fa1ffc4c96..2e0fdbb730b7 100644 --- a/kernel/trace/trace_remote.c +++ b/kernel/trace/trace_remote.c @@ -980,9 +980,12 @@ int trace_remote_alloc_buffer(struct trace_buffer_desc *desc, size_t desc_size, const struct cpumask *cpumask) { size_t min_desc_size = trace_buffer_desc_size(buffer_size, cpumask_weight(cpumask)); - unsigned int nr_pages = max(DIV_ROUND_UP(buffer_size, PAGE_SIZE), 2UL) + 1; struct ring_buffer_desc *rb_desc; int cpu, ret = -ENOMEM; + unsigned int nr_pages; + + if (min_desc_size == SIZE_MAX) + return -E2BIG; if (desc_size < min_desc_size) return -EINVAL; @@ -991,6 +994,7 @@ int trace_remote_alloc_buffer(struct trace_buffer_desc *desc, size_t desc_size, desc->struct_len = min_desc_size; rb_desc = __first_ring_buffer_desc(desc); + nr_pages = max(DIV_ROUND_UP(buffer_size, PAGE_SIZE - BUF_PAGE_HDR_SIZE), 2UL) + 1; for_each_cpu(cpu, cpumask) { unsigned int id; -- 2.55.0.979.g7e5102b832-goog