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From: Yisheng Xie <xieyisheng1@huawei.com>
To: akpm@linux-foundation.org, catalin.marinas@arm.com, mhocko@kernel.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH] kmemcheck: add scheduling point to kmemleak_scan
Date: Fri, 17 Nov 2017 15:03:56 +0800	[thread overview]
Message-ID: <1510902236-4444-1-git-send-email-xieyisheng1@huawei.com> (raw)

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 1024 pages.

Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
---
 mm/kmemleak.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index e4738d5..e9f2e86 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 % 1024))
+				cond_resched();
 		}
 	}
 	put_online_mems();
-- 
1.7.12.4

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             reply	other threads:[~2017-11-17  7:15 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-17  7:03 Yisheng Xie [this message]
2017-11-17 18:27 ` Catalin Marinas
2017-11-20  9:46   ` Yisheng Xie

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