From 9ed5df69b79a22b40b20bc2132ba2495708b19c4 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 24 Feb 2020 18:02:10 +0000 Subject: [PATCH] powerpc/kprobes: Use probe_address() to read instructions In order to avoid Oopses, use probe_address() to read the instruction at the address where the trap happened. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/7f24b5961a6839ff01df792816807f74ff236bf6.1582567319.git.christophe.leroy@c-s.fr --- arch/powerpc/kernel/kprobes.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 227510df8c55..6f96f65ebfe8 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -287,14 +287,18 @@ int kprobe_handler(struct pt_regs *regs) p = get_kprobe(addr); if (!p) { - if (*addr != BREAKPOINT_INSTRUCTION) { + unsigned int instr; + + if (probe_kernel_address(addr, instr)) + goto no_kprobe; + + if (instr != BREAKPOINT_INSTRUCTION) { /* * PowerPC has multiple variants of the "trap" * instruction. If the current instruction is a * trap variant, it could belong to someone else */ - kprobe_opcode_t cur_insn = *addr; - if (is_trap(cur_insn)) + if (is_trap(instr)) goto no_kprobe; /* * The breakpoint instruction was removed right