| From foo@baz Mon Apr 9 17:09:24 CEST 2018 |
| From: Marcin Nowakowski <marcin.nowakowski@imgtec.com> |
| Date: Thu, 8 Jun 2017 15:20:32 +0200 |
| Subject: MIPS: kprobes: flush_insn_slot should flush only if probe initialised |
| |
| From: Marcin Nowakowski <marcin.nowakowski@imgtec.com> |
| |
| |
| [ Upstream commit 698b851073ddf5a894910d63ca04605e0473414e ] |
| |
| When ftrace is used with kprobes, it is possible for a kprobe to contain |
| an invalid location (ie. only initialised to 0 and not to a specific |
| location in the code). Trying to perform a cache flush on such location |
| leads to a crash r4k_flush_icache_range(). |
| |
| Fixes: c1bf207d6ee1 ("MIPS: kprobe: Add support.") |
| Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com> |
| Cc: linux-mips@linux-mips.org |
| Patchwork: https://patchwork.linux-mips.org/patch/16296/ |
| Signed-off-by: Ralf Baechle <ralf@linux-mips.org> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/mips/include/asm/kprobes.h | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/arch/mips/include/asm/kprobes.h |
| +++ b/arch/mips/include/asm/kprobes.h |
| @@ -40,7 +40,8 @@ typedef union mips_instruction kprobe_op |
| |
| #define flush_insn_slot(p) \ |
| do { \ |
| - flush_icache_range((unsigned long)p->addr, \ |
| + if (p->addr) \ |
| + flush_icache_range((unsigned long)p->addr, \ |
| (unsigned long)p->addr + \ |
| (MAX_INSN_SIZE * sizeof(kprobe_opcode_t))); \ |
| } while (0) |
