From b2ba0bd3469546e5bf6f32a0bb67d6ccf21d4584 Mon Sep 17 00:00:00 2001 From: Yisheng Xie Date: Wed, 29 Nov 2017 16:11:08 -0800 Subject: [PATCH] kmemleak: add scheduling point to kmemleak_scan() [ 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(+) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 7780cd8..a1ba553 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1532,6 +1532,8 @@ 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(); -- 2.7.4