From: Linus Torvalds Date: Thu, 29 Jan 2015 19:15:17 +0000 (-0800) Subject: vm: make stack guard page errors return VM_FAULT_SIGSEGV rather than SIGBUS X-Git-Tag: v3.2.67~19 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=a8467a7ab41236cad681a5c3e5f2373625755d42 vm: make stack guard page errors return VM_FAULT_SIGSEGV rather than SIGBUS commit 9c145c56d0c8a0b62e48c8d71e055ad0fb2012ba upstream. The stack guard page error case has long incorrectly caused a SIGBUS rather than a SIGSEGV, but nobody actually noticed until commit fee7e49d4514 ("mm: propagate error from stack expansion even for guard page") because that error case was never actually triggered in any normal situations. Now that we actually report the error, people noticed the wrong signal that resulted. So far, only the test suite of libsigsegv seems to have actually cared, but there are real applications that use libsigsegv, so let's not wait for any of those to break. Reported-and-tested-by: Takashi Iwai Tested-by: Jan Engelhardt Acked-by: Heiko Carstens # "s390 still compiles and boots" Cc: linux-arch@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- diff --git a/mm/memory.c b/mm/memory.c index 816002cc4513..0a7bb38f4c98 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3155,7 +3155,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, /* Check if we need to add a guard page to the stack */ if (check_stack_guard_page(vma, address) < 0) - return VM_FAULT_SIGBUS; + return VM_FAULT_SIGSEGV; /* Use the zero-page for reads */ if (!(flags & FAULT_FLAG_WRITE)) {