Commit 462e00cc authored Jul 15, 2007 by Ethan Solomita Committed by Linus Torvalds Jul 16, 2007

oom: stop allocating user memory if TIF_MEMDIE is set



get_user_pages() can try to allocate a nearly unlimited amount of memory on
behalf of a user process, even if that process has been OOM killed.  The
OOM kill occurs upon return to user space via a SIGKILL, but
get_user_pages() will try allocate all its memory before returning.  Change
get_user_pages() to check for TIF_MEMDIE, and if set then return
immediately.

Signed-off-by: Ethan Solomita <solo@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b71636e2

mm/memory.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -1055,6 +1055,14 @@ int get_user_pages(struct task_struct tsk, struct mm_struct mm,
		do {
		struct page *page;

		/*
		* If tsk is ooming, cut off its access to large memory
		* allocations. It has a pending SIGKILL, but it can't
		* be processed until returning to user space.
		*/
		if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
		return -ENOMEM;

		if (write)
		foll_flags \|= FOLL_WRITE;