Kprobes/arm skips single-stepping (moreover handling the event)
if the conditional instruction must not be executed. This
also applies that rule when we hit a recursing kprobe, so
that the nmissed count isn't incremented in that case.
Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
Acked-by: Jon Medhurst <t...@linaro.org>
---
arch/arm/probes/kprobes/core.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index 264fedb..84989ae 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -265,7 +265,15 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
#endif
if (p) {
- if (cur) {
+ if (!p->ainsn.insn_check_cc(regs->ARM_cpsr)) {
+ /*
+ * Probe hit but conditional execution check failed,
+ * so just skip the instruction and continue as if
+ * nothing had happened.
+ * In this case, we can skip recursing check too.
+ */
+ singlestep_skip(p, regs);
+ } else if (cur) {
/* Kprobe is pending, so we're recursing. */
switch (kcb->kprobe_status) {
case KPROBE_HIT_ACTIVE:
@@ -288,7 +296,7 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
/* impossible cases */
BUG();
}
- } else if (p->ainsn.insn_check_cc(regs->ARM_cpsr)) {
+ } else {
/* Probe hit and conditional execution check ok. */
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
@@ -309,13 +317,6 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
}
reset_current_kprobe();
}
- } else {
- /*
- * Probe hit but conditional execution check failed,
- * so just skip the instruction and continue as if
- * nothing had happened.
- */
- singlestep_skip(p, regs);
}
} else if (cur) {
/* We probably hit a jprobe. Call its break handler. */
