From patchwork Mon Dec 20 14:34:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 526537 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AFC30C433F5 for ; Mon, 20 Dec 2021 14:41:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234205AbhLTOlM (ORCPT ); Mon, 20 Dec 2021 09:41:12 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:53944 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230331AbhLTOj4 (ORCPT ); Mon, 20 Dec 2021 09:39:56 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 0074CCE110C; Mon, 20 Dec 2021 14:39:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3B64C36B03; Mon, 20 Dec 2021 14:39:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640011193; bh=nXozThGBMgnmYCx2Uwly7tb+lU5/ML1dXMm5km/IDY0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Qk2XJ5l9HOQo3FNtfqyXYr97kICcQalHxDwWGAC0Sf9DBHRy4v/bLRdPOttkXQn5i TWkfztdtJHeNkwqR6/IbVABN80G0RQf39lFe8T/fmlxYoyMGLmKbO1h74SbMB3bYEJ DUjd33MmcFuC7BEKJFGr9syJYptNzfcCdWj1nlpY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chen Jun , "Steven Rostedt (VMware)" , Sasha Levin Subject: [PATCH 4.14 07/45] tracing: Fix a kmemleak false positive in tracing_map Date: Mon, 20 Dec 2021 15:34:02 +0100 Message-Id: <20211220143022.514634932@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211220143022.266532675@linuxfoundation.org> References: <20211220143022.266532675@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Chen Jun [ Upstream commit f25667e5980a4333729cac3101e5de1bb851f71a ] Doing the command: echo 'hist:key=common_pid.execname,common_timestamp' > /sys/kernel/debug/tracing/events/xxx/trigger Triggers many kmemleak reports: unreferenced object 0xffff0000c7ea4980 (size 128): comm "bash", pid 338, jiffies 4294912626 (age 9339.324s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0 [<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178 [<00000000633bd154>] tracing_map_init+0x1f8/0x268 [<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0 [<00000000bf8520ed>] trigger_process_regex+0xd4/0x128 [<00000000f549355a>] event_trigger_write+0x7c/0x120 [<00000000b80f898d>] vfs_write+0xc4/0x380 [<00000000823e1055>] ksys_write+0x74/0xf8 [<000000008a9374aa>] __arm64_sys_write+0x24/0x30 [<0000000087124017>] do_el0_svc+0x88/0x1c0 [<00000000efd0dcd1>] el0_svc+0x1c/0x28 [<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0 [<00000000e7399680>] el0_sync+0x148/0x180 unreferenced object 0xffff0000c7ea4980 (size 128): comm "bash", pid 338, jiffies 4294912626 (age 9339.324s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0 [<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178 [<00000000633bd154>] tracing_map_init+0x1f8/0x268 [<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0 [<00000000bf8520ed>] trigger_process_regex+0xd4/0x128 [<00000000f549355a>] event_trigger_write+0x7c/0x120 [<00000000b80f898d>] vfs_write+0xc4/0x380 [<00000000823e1055>] ksys_write+0x74/0xf8 [<000000008a9374aa>] __arm64_sys_write+0x24/0x30 [<0000000087124017>] do_el0_svc+0x88/0x1c0 [<00000000efd0dcd1>] el0_svc+0x1c/0x28 [<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0 [<00000000e7399680>] el0_sync+0x148/0x180 The reason is elts->pages[i] is alloced by get_zeroed_page. and kmemleak will not scan the area alloced by get_zeroed_page. The address stored in elts->pages will be regarded as leaked. That is, the elts->pages[i] will have pointers loaded onto it as well, and without telling kmemleak about it, those pointers will look like memory without a reference. To fix this, call kmemleak_alloc to tell kmemleak to scan elts->pages[i] Link: https://lkml.kernel.org/r/20211124140801.87121-1-chenjun102@huawei.com Signed-off-by: Chen Jun Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Sasha Levin --- kernel/trace/tracing_map.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -24,6 +24,7 @@ #include #include #include +#include #include "tracing_map.h" #include "trace.h" @@ -227,6 +228,7 @@ void tracing_map_array_free(struct traci for (i = 0; i < a->n_pages; i++) { if (!a->pages[i]) break; + kmemleak_free(a->pages[i]); free_page((unsigned long)a->pages[i]); } @@ -262,6 +264,7 @@ struct tracing_map_array *tracing_map_ar a->pages[i] = (void *)get_zeroed_page(GFP_KERNEL); if (!a->pages[i]) goto free; + kmemleak_alloc(a->pages[i], PAGE_SIZE, 1, GFP_KERNEL); } out: return a;