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Patch "parisc: Report SIGSEGV instead of SIGBUS when running out of stack" has been added to the 4.4-stable tree

PATCH [email protected] 1 participant 1 message Jul 18, 2017

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This is a note to let you know that I've just added the patch titled

parisc: Report SIGSEGV instead of SIGBUS when running out of stack

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
parisc-report-sigsegv-instead-of-sigbus-when-running-out-of-stack.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 247462316f85a9e0479445c1a4223950b68ffac1 Mon Sep 17 00:00:00 2001

From: Helge Deller <[email protected]>
Date: Sun, 2 Jul 2017 22:00:41 +0200
Subject: parisc: Report SIGSEGV instead of SIGBUS when running out of stack

From: Helge Deller <[email protected]>

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.

---
 arch/parisc/mm/fault.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/parisc/mm/fault.c +1 -1
@@ -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;

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/parisc-use-compat_sys_keyctl.patch queue-4.4/parisc-dma-api-return-error-instead-of-bug_on-for-dma-ops-on-non-dma-devs.patch queue-4.4/parisc-mm-ensure-irqs-are-off-in-switch_mm.patch queue-4.4/parisc-report-sigsegv-instead-of-sigbus-when-running-out-of-stack.patch