From: Peter Zijlstra <peterz@infradead.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>,
Suleiman Souhlal <suleiman@google.com>, bpf <bpf@vger.kernel.org>,
linux-kernel@vger.kernel.org, Borislav Petkov <bp@suse.de>,
Josh Poimboeuf <jpoimboe@kernel.org>,
x86@kernel.org
Subject: Re: [PATCH 1/2] x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK
Date: Wed, 7 Sep 2022 10:11:16 +0200 [thread overview]
Message-ID: <YxhSJBiNJ5QRLQX8@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YxhQIBKzi+L0KDhc@hirez.programming.kicks-ass.net>
On Wed, Sep 07, 2022 at 10:02:41AM +0200, Peter Zijlstra wrote:
> Maybe something like:
>
> struct queue {
> int head, tail;
> unsigned long val[16]; /* insufficient; probably should allocate something */
> };
>
> void push(struct queue *q, unsigned long val)
> {
> /* break loops, been here already */
> for (int i = 0; i < q->head; i++) {
> if (q->val[i] == val)
> return;
> }
>
> q->val[q->head++] = val;
>
> WARN_ON(q->head > ARRAY_SIZE(q->val)
> }
>
> unsigned long pop(struct queue *q)
> {
> if (q->tail == q->head)
> return 0;
>
> return q->val[q->tail++];
> }
>
> bool dead_end_insn(struct instruction *insn)
> {
> switch (insn->opcode.bytes[0]) {
> case INT3_INSN_OPCODE:
> case JMP8_INSN_OPCODE:
> case JMP32_INSN_OPCODE:
case RET_INSN_OPCODE:
> return true; /* no arch execution after these */
>
> case 0xff:
> /* jmp *%reg; jmpf */
> if (modrm_reg == 4 || modrm_reg == 5)
> return true;
> break;
>
> default:
> break;
> }
>
> return false;
> }
>
>
>
> 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;
> }
> }
>
>
>
> It's a bit of a pain, but I think it should cover things.
next prev parent reply other threads:[~2022-09-07 8:11 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-07 0:55 [PATCH 0/2] x86/kprobes: Fixes for CONFIG_RETHUNK Masami Hiramatsu (Google)
2022-09-07 0:55 ` [PATCH 1/2] x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK Masami Hiramatsu (Google)
2022-09-07 7:06 ` Peter Zijlstra
2022-09-07 9:01 ` [PATCH] objtool,x86: Teach decode about LOOP* instructions Peter Zijlstra
2022-09-07 9:06 ` David Laight
2022-09-07 9:40 ` Peter Zijlstra
2022-09-07 11:13 ` David Laight
2022-09-15 14:24 ` [tip: objtool/core] " tip-bot2 for Peter Zijlstra
2022-09-07 9:12 ` [PATCH 1/2] x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK Masami Hiramatsu
2022-09-07 9:38 ` Peter Zijlstra
2022-09-07 9:53 ` Masami Hiramatsu
2022-09-07 8:02 ` Peter Zijlstra
2022-09-07 8:11 ` Peter Zijlstra [this message]
2022-09-07 9:49 ` Masami Hiramatsu
2022-09-07 10:19 ` Peter Zijlstra
2022-09-07 11:44 ` Peter Zijlstra
2022-09-07 13:05 ` Peter Zijlstra
2022-09-07 14:14 ` Masami Hiramatsu
2022-09-07 14:27 ` Peter Zijlstra
2022-09-07 15:22 ` Masami Hiramatsu
2022-09-07 12:56 ` Peter Zijlstra
2022-09-07 13:49 ` Masami Hiramatsu
2022-09-07 14:28 ` Peter Zijlstra
2022-09-07 12:59 ` Peter Zijlstra
2022-09-07 13:53 ` Masami Hiramatsu
2022-09-07 0:55 ` [PATCH 2/2] x86/kprobes: Fix optprobe optimization " Masami Hiramatsu (Google)
2022-09-07 6:52 ` [PATCH 0/2] x86/kprobes: Fixes for CONFIG_RETHUNK Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YxhSJBiNJ5QRLQX8@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=bp@suse.de \
--cc=bpf@vger.kernel.org \
--cc=jpoimboe@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mhiramat@kernel.org \
--cc=mingo@kernel.org \
--cc=rostedt@goodmis.org \
--cc=suleiman@google.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).