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/[email protected] Signed-off-by: Mathieu Desnoyers <[email protected]> Reported-by: Robert Berger <[email protected]> Tested-by: Robert Berger <[email protected]> CC: Robert Berger <[email protected]> CC: Masami Hiramatsu <[email protected]> CC: William Cohen <[email protected]> CC: Laura Abbott <[email protected]> CC: Kees Cook <[email protected]> CC: Russell King <[email protected]> CC: <[email protected]> # v4.14+ --- arch/arm/probes/kprobes/opt-arm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/probes/kprobes/opt-arm.c b/arch/arm/probes/kprobes/opt-arm.c index 2c118a6ab358..0dc23fc227ed 100644 --- 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 optimized_kprobe *op, struct kprobe *or } /* 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. */ -- 2.11.0
