From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 2B9FF6B0033 for ; Thu, 23 Nov 2017 07:32:58 -0500 (EST) Received: by mail-pf0-f199.google.com with SMTP id c83so16937715pfj.11 for ; Thu, 23 Nov 2017 04:32:58 -0800 (PST) Received: from huawei.com ([45.249.212.32]) by mx.google.com with ESMTPS id a3si10630336pld.306.2017.11.23.04.32.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 23 Nov 2017 04:32:57 -0800 (PST) From: Yisheng Xie Subject: [PATCH v2] kmemleak: add scheduling point to kmemleak_scan Date: Thu, 23 Nov 2017 20:23:08 +0800 Message-ID: <1511439788-20099-1-git-send-email-xieyisheng1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, catalin.marinas@arm.com, mhocko@kernel.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, xieyisheng1@huawei.com kmemleak_scan will scan struct page for each node and it can be really large and resulting in a soft lockup. We have seen a soft lockup when do scan while compile kernel: [ 220.561051] watchdog: BUG: soft lockup - CPU#53 stuck for 22s! [bash:10287] [...] [ 220.753837] Call Trace: [ 220.756296] kmemleak_scan+0x21a/0x4c0 [ 220.760034] kmemleak_write+0x312/0x350 [ 220.763866] ? do_wp_page+0x147/0x4c0 [ 220.767521] full_proxy_write+0x5a/0xa0 [ 220.771351] __vfs_write+0x33/0x150 [ 220.774833] ? __inode_security_revalidate+0x4c/0x60 [ 220.779782] ? selinux_file_permission+0xda/0x130 [ 220.784479] ? _cond_resched+0x15/0x30 [ 220.788221] vfs_write+0xad/0x1a0 [ 220.791529] SyS_write+0x52/0xc0 [ 220.794758] do_syscall_64+0x61/0x1a0 [ 220.798411] entry_SYSCALL64_slow_path+0x25/0x25 Fix this by adding cond_resched every MAX_SCAN_SIZE. Suggested-by: Catalin Marinas Signed-off-by: Yisheng Xie --- v2: * call cond_resched() every MAX_SCAN_SIZE for consistency with the other places * fix the subject of the patch. - Both per Catalin mm/kmemleak.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index e4738d5..3d47817 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1523,6 +1523,8 @@ static void kmemleak_scan(void) if (page_count(page) == 0) continue; scan_block(page, page + 1, NULL); + if (!(pfn % (MAX_SCAN_SIZE / sizeof(*page)))) + cond_resched(); } } put_online_mems(); -- 1.7.12.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org