Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH 04/10] arm64: kprobes: Record frame pointer with kretprobe instance | Date | Fri, 15 Oct 2021 21:51:19 +0900 |
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Record the frame pointer instead of stack address with kretprobe instance as the identifier on the instance list. Since arm64 always enable CONFIG_FRAME_POINTER, we can use the actual frame pointer (x29).
This will allow the stacktrace code to find the original return address from the FP alone.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> --- Changes in v2: - Update changelog according to Mark's comment. --- arch/arm64/kernel/probes/kprobes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index e7ad6da980e8..d9dfa82c1f18 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -401,14 +401,14 @@ int __init arch_populate_kprobe_blacklist(void) void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs) { - return (void *)kretprobe_trampoline_handler(regs, (void *)kernel_stack_pointer(regs)); + return (void *)kretprobe_trampoline_handler(regs, (void *)regs->regs[29]); } void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { ri->ret_addr = (kprobe_opcode_t *)regs->regs[30]; - ri->fp = (void *)kernel_stack_pointer(regs); + ri->fp = (void *)regs->regs[29]; /* replace return addr (x30) with trampoline */ regs->regs[30] = (long)&__kretprobe_trampoline;
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