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 12D42612D7; Tue, 20 Feb 2024 21:21:40 +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=1708464101; cv=none; b=FFjn6iuwyU2+3eJTsPRGXc1edtP6cKXICdlYCQrdT6mGAyCc/1Iw1hWW61MbmsSm/31M/QpH3Pj80iIu41nLaLg5K45IqmC6exNc2mW7nBbOnNZr3AdS9semk2rOPsE0LvriwlAtzMs7v/Ez2vPT03yTeel7hlApa90lXy8Ts40= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708464101; c=relaxed/simple; bh=VKMLUV20Xv+wZJG/8trb8+o0cQvga63jkY1X/6F4Pdk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TE/v+JqBcncJHtJAPIeNnKwc4RKRGtbFUKBNQny73gW/8Dyn6m6tMLUXtvqKGD4UM+KUnG9sPla4R9mrya33qvMMIPLY0aEYgMi8AdpzoTncynT7niP/FzJbr1J1r3zYdQ3ug09O/kyH/O3F536dgObuCrlcQan4wN9+8bk6qoA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IYgPeiXm; 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="IYgPeiXm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 26E01C433C7; Tue, 20 Feb 2024 21:21:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708464100; bh=VKMLUV20Xv+wZJG/8trb8+o0cQvga63jkY1X/6F4Pdk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IYgPeiXmNrU8Nua+1VbDgF4awa0rELpGkV/JGB1j2JzRmqLq+97xHmj/0efL9640r TYlnibfSc8h21iqiJAIO5bEVhmf+VHFW6tgSGzNoGFcsR75saTbZGJkywFBjMF47Cx a7US0cKxKX/vgvgQwUXuIjHZ4ZcIhOgef0SLkFZs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Mathieu Desnoyers , Catalin Marinas , Kalle Valo , "Steven Rostedt (Google)" Subject: [PATCH 6.6 252/331] tracing: Inform kmemleak of saved_cmdlines allocation Date: Tue, 20 Feb 2024 21:56:08 +0100 Message-ID: <20240220205645.758864010@linuxfoundation.org> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240220205637.572693592@linuxfoundation.org> References: <20240220205637.572693592@linuxfoundation.org> User-Agent: quilt/0.67 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: Steven Rostedt (Google) commit 2394ac4145ea91b92271e675a09af2a9ea6840b7 upstream. The allocation of the struct saved_cmdlines_buffer structure changed from: s = kmalloc(sizeof(*s), GFP_KERNEL); s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL); to: orig_size = sizeof(*s) + val * TASK_COMM_LEN; order = get_order(orig_size); size = 1 << (order + PAGE_SHIFT); page = alloc_pages(GFP_KERNEL, order); if (!page) return NULL; s = page_address(page); memset(s, 0, sizeof(*s)); s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL); Where that s->saved_cmdlines allocation looks to be a dangling allocation to kmemleak. That's because kmemleak only keeps track of kmalloc() allocations. For allocations that use page_alloc() directly, the kmemleak needs to be explicitly informed about it. Add kmemleak_alloc() and kmemleak_free() around the page allocation so that it doesn't give the following false positive: unreferenced object 0xffff8881010c8000 (size 32760): comm "swapper", pid 0, jiffies 4294667296 hex dump (first 32 bytes): ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ backtrace (crc ae6ec1b9): [] kmemleak_alloc+0x45/0x80 [] __kmalloc_large_node+0x10d/0x190 [] __kmalloc+0x3b1/0x4c0 [] allocate_cmdlines_buffer+0x113/0x230 [] tracer_alloc_buffers.isra.0+0x124/0x460 [] early_trace_init+0x14/0xa0 [] start_kernel+0x12e/0x3c0 [] x86_64_start_reservations+0x18/0x30 [] x86_64_start_kernel+0x7b/0x80 [] secondary_startup_64_no_verify+0x15e/0x16b Link: https://lore.kernel.org/linux-trace-kernel/87r0hfnr9r.fsf@kernel.org/ Link: https://lore.kernel.org/linux-trace-kernel/20240214112046.09a322d6@gandalf.local.home Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Catalin Marinas Fixes: 44dc5c41b5b1 ("tracing: Fix wasted memory in saved_cmdlines logic") Reported-by: Kalle Valo Tested-by: Kalle Valo Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -39,6 +39,7 @@ #include #include #include +#include #include #include #include @@ -2330,6 +2331,7 @@ static void free_saved_cmdlines_buffer(s int order = get_order(sizeof(*s) + s->cmdline_num * TASK_COMM_LEN); kfree(s->map_cmdline_to_pid); + kmemleak_free(s); free_pages((unsigned long)s, order); } @@ -2349,6 +2351,7 @@ static struct saved_cmdlines_buffer *all return NULL; s = page_address(page); + kmemleak_alloc(s, size, 1, GFP_KERNEL); memset(s, 0, sizeof(*s)); /* Round up to actual allocation */