Merge branch 'sh4-sid' into 'sid'

[sh4]: Check for kprobe trap number before trying to handle a kprobe trap

See merge request kernel-team/linux!152

debian/changelog

@@ -1,5 +1,8 @@
 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
+
   [ Salvatore Bonaccorso ]
   * tcp: refine memory limit test in tcp_fragment() (Closes: #930904)
 

debian/patches/bugfix/sh/sh-check-for-kprobe-trap-number-before-trying-to-handle-a-kprobe-trap.patch

@@ -0,0 +1,40 @@
+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
+Origin: https://marc.info/?l=linux-sh&m=156034655921917&w=2
+
+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
+

debian/patches/series

@@ -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