From f6e1c74f566453964887e7845570689d1511cd2d Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Wed, 25 Sep 2019 16:47:33 -0700 Subject: kexec: bail out upon SIGKILL when allocating memory. commit 7c3a6aedcd6aae0a32a527e68669f7dd667492d1 upstream. syzbot found that a thread can stall for minutes inside kexec_load() after that thread was killed by SIGKILL [1]. It turned out that the reproducer was trying to allocate 2408MB of memory using kimage_alloc_page() from kimage_load_normal_segment(). Let's check for SIGKILL before doing memory allocation. [1] https://syzkaller.appspot.com/bug?id=a0e3436829698d5824231251fad9d8e998f94f5e Link: http://lkml.kernel.org/r/993c9185-d324-2640-d061-bed2dd18b1f7@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa Reported-by: syzbot Cc: Eric Biederman Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- kernel/kexec_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index d5870723b8ad..15d70a90b50d 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -300,6 +300,8 @@ static struct page *kimage_alloc_pages(gfp_t gfp_mask, unsigned int order) { struct page *pages; + if (fatal_signal_pending(current)) + return NULL; pages = alloc_pages(gfp_mask & ~__GFP_ZERO, order); if (pages) { unsigned int count, i; -- cgit v1.2.3