Patch "ARM: 8834/1: Fix: kprobes: optimized kprobes illegal instruction" has been added to the 4.20-stable tree

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

    ARM: 8834/1: Fix: kprobes: optimized kprobes illegal instruction

to the 4.20-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:
     arm-8834-1-fix-kprobes-optimized-kprobes-illegal-instruction.patch
and it can be found in the queue-4.20 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let [off-list ref] know about it.


From 0ac569bf6a7983c0c5747d6df8db9dc05bc92b6c Mon Sep 17 00:00:00 2001
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 5 Feb 2019 16:37:40 +0100
Subject: ARM: 8834/1: Fix: kprobes: optimized kprobes illegal instruction

From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

commit 0ac569bf6a7983c0c5747d6df8db9dc05bc92b6c upstream.

commit e46daee53bb5 ("ARM: 8806/1: kprobes: Fix false positive with
FORTIFY_SOURCE") introduced a regression in optimized kprobes. It
triggers "invalid instruction" oopses when using kprobes instrumentation
through lttng and perf. This commit was introduced in kernel v4.20, and
has been backported to stable kernels 4.19 and 4.14.

This crash was also reported by Hongzhi Song on the redhat bugzilla
where the patch was originally introduced.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1639397
Link: https://bugs.lttng.org/issues/1174
Link: https://lore.kernel.org/lkml/342740659.2887.1549307721609.JavaMail.zimbra@efficios.com (local)

Fixes: e46daee53bb5 ("ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reported-by: Robert Berger <redacted>
Tested-by: Robert Berger <redacted>
Acked-by: Kees Cook <redacted>
Cc: Robert Berger <redacted>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: William Cohen <redacted>
Cc: Laura Abbott <redacted>
Cc: Kees Cook <redacted>
Cc: <redacted> # v4.14+
Cc: linux-arm-kernel@lists.infradead.org
Cc: patches@armlinux.org.uk
Signed-off-by: Russell King <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm/probes/kprobes/opt-arm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/probes/kprobes/opt-arm.c
+++ b/arch/arm/probes/kprobes/opt-arm.c

@@ -247,7 +247,7 @@ int arch_prepare_optimized_kprobe(struct
 	}
 
 	/* Copy arch-dep-instance from template. */
-	memcpy(code, (unsigned char *)optprobe_template_entry,
+	memcpy(code, (unsigned long *)&optprobe_template_entry,
 			TMPL_END_IDX * sizeof(kprobe_opcode_t));
 
 	/* Adjust buffer according to instruction. */

Patches currently in stable-queue which might be from mathieu.desnoyers@efficios.com are

queue-4.20/arm-8834-1-fix-kprobes-optimized-kprobes-illegal-instruction.patch

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