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Date: Fri, 2 Feb 2018 17:58:13 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Yisheng Xie <xieyisheng1@...wei.com>,
Catalin Marinas <catalin.marinas@....com>,
Michal Hocko <mhocko@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.9 53/86] kmemleak: add scheduling point to kmemleak_scan()
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yisheng Xie <xieyisheng1@...wei.com>
[ 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 <xieyisheng1@...wei.com>
Suggested-by: Catalin Marinas <catalin.marinas@....com>
Acked-by: Catalin Marinas <catalin.marinas@....com>
Cc: Michal Hocko <mhocko@...nel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
mm/kmemleak.c | 2 ++
1 file changed, 2 insertions(+)
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1442,6 +1442,8 @@ 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();
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