From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227CYJFNtlZJNcPaFWiKE6WRA7YtkeopGPFwyAdre28RcNUwVOm6iVmMgMmm8e2iLXr0zmNl ARC-Seal: i=1; a=rsa-sha256; t=1517590887; cv=none; d=google.com; s=arc-20160816; b=IJXFPgmTSnPS8qQIQI15K9X13DtveOCkCN7593qKh8hoel1MHzOODHKxxMhSK2rCD2 ayg6kUUj84qs3hwmVdtG1viFLnaayMVavPTtdAL1J/TJxDxnZpOPE9nbLdYNZshJuMrc LUaZHhvsxCBZjp+IDGFOOgH0TbO1KK+HhT2pN0mN6BJBS9YI/pm0cAiiO1SBEgyyc/FN +JTuLUFMe847gpMJrsm47UIzfgry4V0hYxCWGBiQCRyIwQQZvK6dSIZ9c7PcAOqyP4p0 GY7GvsBxm/hTkFfOnnec+P1jMKWYj2v2eaYlPDrJkgw7D5P3vq0Hi7jCYK+TmrRH7s72 lHPg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=Ad5aY8JiyQZLr3H/PrHdHozNY9L1tOg34j/rcqN9ocA=; b=LCAlEFFGT+p+mRVvfbdjZFCPffNTMcNnEymhdSMIfn/VzP3L/QqFf06RSDBRzM/dzu Ag5o7APYSbj5e990Vxz0NVNYPQ14gabQYjY7C7NaUMz+bjVGqwmQF371BnmvsOJS++Ec 2/tAL6t/joaOzBdGyddRmBDuAyAG96GIrfm3opUnpoHstRDDzIQjDlmRrBhbrfCfgCMZ PNHbhTxigQQ++Mrl5fcv3NrrlWfX4te0T8qgus7RqqFuJuTNQ2JoCmlUiLD+F6lDEYIb n5h17pmoeajA6pKnak8Urkfsga3wrMop+2ElH0BVSswJzLrna2skTnMN1+7lYtwj2R85 QuSg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yisheng Xie , Catalin Marinas , Michal Hocko , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.4 47/67] kmemleak: add scheduling point to kmemleak_scan() Date: Fri, 2 Feb 2018 17:58:16 +0100 Message-Id: <20180202140820.602701736@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180202140815.091718203@linuxfoundation.org> References: <20180202140815.091718203@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1591309382786408029?= X-GMAIL-MSGID: =?utf-8?q?1591309382786408029?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yisheng Xie [ Upstream commit bde5f6bc68db51128f875a756e9082a6c6ff7b4c ] 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: watchdog: BUG: soft lockup - CPU#53 stuck for 22s! [bash:10287] [...] Call Trace: kmemleak_scan+0x21a/0x4c0 kmemleak_write+0x312/0x350 full_proxy_write+0x5a/0xa0 __vfs_write+0x33/0x150 vfs_write+0xad/0x1a0 SyS_write+0x52/0xc0 do_syscall_64+0x61/0x1a0 entry_SYSCALL64_slow_path+0x25/0x25 Fix this by adding cond_resched every MAX_SCAN_SIZE. Link: http://lkml.kernel.org/r/1511439788-20099-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie Suggested-by: Catalin Marinas Acked-by: Catalin Marinas Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- mm/kmemleak.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1394,6 +1394,8 @@ 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();