| From 9c145c56d0c8a0b62e48c8d71e055ad0fb2012ba Mon Sep 17 00:00:00 2001 |
| From: Linus Torvalds <torvalds@linux-foundation.org> |
| Date: Thu, 29 Jan 2015 11:15:17 -0800 |
| Subject: vm: make stack guard page errors return VM_FAULT_SIGSEGV rather than SIGBUS |
| |
| From: Linus Torvalds <torvalds@linux-foundation.org> |
| |
| 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 <tiwai@suse.de> |
| Tested-by: Jan Engelhardt <jengelh@inai.de> |
| Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots" |
| Cc: linux-arch@vger.kernel.org |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/memory.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/mm/memory.c |
| +++ b/mm/memory.c |
| @@ -2645,7 +2645,7 @@ static int do_anonymous_page(struct mm_s |
| |
| /* 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)) { |
