[PATCH 3.16 081/192] parisc: Report SIGSEGV instead of SIGBUS when running out of stack

Ben Hutchings
2017-10-09T12:51:31Z

From: Helge Deller <deller@gmx.de>

commit 247462316f85a9e0479445c1a4223950b68ffac1 upstream.

When a process runs out of stack the parisc kernel wrongly faults with SIGBUS
instead of the expected SIGSEGV signal.

This example shows how the kernel faults:
do_page_fault() command='a.out' type=15 address=0xfaac2000 in libc-2.24.so[f8308000+16c000]
trap #15: Data TLB miss fault, vm_start = 0xfa2c2000, vm_end = 0xfaac2000

The vma->vm_end value is the first address which does not belong to the vma, so
adjust the check to include vma->vm_end to the range for which to send the
SIGSEGV signal.

This patch unbreaks building the debian libsigsegv package.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/parisc/mm/fault.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -303,7 +303,7 @@ bad_area:
case 15: /* Data TLB miss fault/Data page fault */
/* send SIGSEGV when outside of vma */
if (!vma ||
- address < vma->vm_start || address > vma->vm_end) {
+ address < vma->vm_start || address >= vma->vm_end) {
si.si_signo = SIGSEGV;
si.si_code = SEGV_MAPERR;
break;