The patch titled
Subject: kmemleak: add scheduling point to kmemleak_scan()
has been added to the -mm tree. Its filename is
kmemleak-add-scheduling-point-to-kmemleak_scan.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kmemleak-add-scheduling-point-to-kmemleak_scan.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kmemleak-add-scheduling-point-to-kmemleak_scan.patch
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------------------------------------------------------
From: Yisheng Xie <xieyisheng1@xxxxxxxxxx>
Subject: kmemleak: add scheduling point to kmemleak_scan()
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.
Link: http://lkml.kernel.org/r/1511439788-20099-1-git-send-email-xieyisheng1@xxxxxxxxxx
Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx>
Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kmemleak.c | 2 ++
1 file changed, 2 insertions(+)
diff -puN mm/kmemleak.c~kmemleak-add-scheduling-point-to-kmemleak_scan mm/kmemleak.c
--- a/mm/kmemleak.c~kmemleak-add-scheduling-point-to-kmemleak_scan
+++ a/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();
_
Patches currently in -mm which might be from xieyisheng1@xxxxxxxxxx are
kmemleak-add-scheduling-point-to-kmemleak_scan.patch
mm-mempolicy-remove-redundant-check-in-get_nodes.patch
mm-mempolicy-fix-the-check-of-nodemask-from-user.patch
mm-mempolicy-add-nodes_empty-check-in-sysc_migrate_pages.patch
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