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-Url: https://git.stricted.de/?a=commitdiff_plain;h=9c145c56d0c8a0b62e48c8d71e055ad0fb2012ba;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git vm: make stack guard page errors return VM_FAULT_SIGSEGV rather than SIGBUS 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 Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds --- diff --git a/mm/memory.c b/mm/memory.c index 54f3a9b00956..2c3536cc6c63 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2632,7 +2632,7 @@ 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) && !mm_forbids_zeropage(mm)) {