This is a note to let you know that I've just added the patch titled

kmemleak: add scheduling point to kmemleak_scan()

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: kmemleak-add-scheduling-point-to-kmemleak_scan.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Feb 1 13:45:42 CET 2018

From: Yisheng Xie xieyisheng1@huawei.com Date: Wed, 29 Nov 2017 16:11:08 -0800 Subject: kmemleak: add scheduling point to kmemleak_scan()

From: Yisheng Xie xieyisheng1@huawei.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@huawe... Signed-off-by: Yisheng Xie xieyisheng1@huawei.com Suggested-by: Catalin Marinas catalin.marinas@arm.com Acked-by: Catalin Marinas catalin.marinas@arm.com Cc: Michal Hocko mhocko@kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/kmemleak.c | 2 ++ 1 file changed, 2 insertions(+)

--- 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();

Patches currently in stable-queue which might be from xieyisheng1@huawei.com are

queue-4.14/kmemleak-add-scheduling-point-to-kmemleak_scan.patch