...
 
linux (4.19.37-6) UNRELEASED; urgency=medium
[ John Paul Adrian Glaubitz ]
* [sh4]: Check for kprobe trap number before trying to handle a kprobe trap
-- John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Sat, 22 Jun 2019 23:23:47 +0200
linux (4.19.37-5) unstable; urgency=medium
[ Romain Perier ]
......
From 6d7cc74d8aad33589c6cc6f38e33c4284abc07b8 Mon Sep 17 00:00:00 2001
From: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
Date: Wed, 12 Jun 2019 15:08:37 +0200
Subject: [PATCH 1/1] arch/sh: Check for kprobe trap number before trying to
handle a kprobe trap
The DIE_TRAP notifier chain is run both for kprobe traps and for BUG/WARN
traps. The kprobe code assumes to be only called for
BREAKPOINT_INSTRUCTION, and concludes to have hit a concurrently removed
kprobe if it finds anything else at the faulting locations. This includes
TRAPA_BUG_OPCODE used for BUG and WARN.
The consequence is that kprobe_handler returns 1. This makes
kprobe_exceptions_notify return NOTIFY_STOP, and prevents handling the BUG
statement. This also prevents moving $pc away from the trap instruction,
so the system locks up in an endless loop
Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
---
arch/sh/kernel/kprobes.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/sh/kernel/kprobes.c b/arch/sh/kernel/kprobes.c
index 1f8c0d30567f..318296f48f1a 100644
--- a/arch/sh/kernel/kprobes.c
+++ b/arch/sh/kernel/kprobes.c
@@ -485,7 +485,8 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
addr = (kprobe_opcode_t *) (args->regs->pc);
- if (val == DIE_TRAP) {
+ if (val == DIE_TRAP &&
+ args->trapnr == (BREAKPOINT_INSTRUCTION & 0xff)) {
if (!kprobe_running()) {
if (kprobe_handler(args->regs)) {
ret = NOTIFY_STOP;
--
2.11.0
......@@ -69,6 +69,7 @@ bugfix/x86/platform-x86-ideapad-laptop-add-ideapad-v510-15ikb-t.patch
bugfix/x86/platform-x86-ideapad-laptop-add-several-models-to-no.patch
bugfix/x86/perf-tools-fix-unwind-build-on-i386.patch
bugfix/sh/sh-boot-do-not-use-hyphen-in-exported-variable-name.patch
bugfix/sh/sh-check-for-kprobe-trap-number-before-trying-to-handle-a-kprobe-trap.patch
bugfix/powerpc/powerpc-lib-sstep-fix-building-for-powerpcspe.patch
bugfix/powerpc/powerpc-lib-makefile-don-t-pull-in-quad.o-for-32-bit.patch
bugfix/arm/arm-mm-export-__sync_icache_dcache-for-xen-privcmd.patch
......