Messages in this thread | | | Date | Wed, 7 Sep 2022 23:14:50 +0900 | From | Masami Hiramatsu (Google) <> | Subject | Re: [PATCH 1/2] x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK |
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On Wed, 7 Sep 2022 15:05:13 +0200 Peter Zijlstra <peterz@infradead.org> wrote:
> On Wed, Sep 07, 2022 at 10:02:41AM +0200, Peter Zijlstra wrote: > > > struct queue q; > > > > start = paddr - offset; > > end = start + size; > > push(&q, paddr - offset); > > > > while (start = pop(&q)) { > > for_each_insn(&insn, start, end, buf) { > > if (insn.kaddr == paddr) > > return 1; > > > > target = insn_get_branch_addr(&insn); > > if (target) > > push(&q, target); > > > > if (dead_end_insn(&insn)) > > break; > > } > > } > > There is the very rare case of intra-function-calls; but I *think* > they're all in noinstr/nokprobe code anyway. > > For instance we have RSB stuffing code like: > > .rept 16 > call 1f; > int3 > 1: > .endr > add $(BITS_PER_LONG/8) * 16, %_ASM_SP > > And the proposed will be horribly confused by that. But like said; it > should also never try and untangle it.
Yeah, but I guess if we break the decoding (internal) loop when we hit an INT3, it maybe possible to be handled?
Thank you,
-- Masami Hiramatsu (Google) <mhiramat@kernel.org>
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