From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Subject: kexec: bail out upon SIGKILL when allocating memory. 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@xxxxxxxxxxxxxxxxxxx Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Reported-by: syzbot <syzbot+8ab2d0f39fb79fe6ca40@xxxxxxxxxxxxxxxxxxxxxxxxx> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/kexec_core.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/kexec_core.c~kexec-bail-out-upon-sigkill-when-allocating-memory +++ a/kernel/kexec_core.c @@ -300,6 +300,8 @@ static struct page *kimage_alloc_pages(g { struct page *pages; + if (fatal_signal_pending(current)) + return NULL; pages = alloc_pages(gfp_mask & ~__GFP_ZERO, order); if (pages) { unsigned int count, i; _
