From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthieu Baerts <matttbe@kernel.org>,
x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org,
Huacai Chen <chenhuacai@loongson.cn>,
Jinyang He <hejinyang@loongson.cn>,
Tiezhu Yang <yangtiezhu@loongson.cn>,
"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>
Subject: Re: [PATCH -tip v2] x86/kprobes: Drop removed INT3 handling code
Date: Sun, 21 Jan 2024 10:42:49 -0500 [thread overview]
Message-ID: <20240121104249.3997125b@rorschach.local.home> (raw)
In-Reply-To: <20240121180544.8c663977651d2a18291318d5@kernel.org>
On Sun, 21 Jan 2024 18:05:44 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> However, if the I-cache entry servives text_poke() and sync_core(), this
> problem may happen.
> The text_poke() flushes TLB but for the local (!global) PTE, and sync_core()
> just serialize (!= cache flushing?). Thus the other CPUs can still see the
Yes, the purpose of the IPIs are for cache flushing, including icache.
> INT3 after text_poke_sync()? If so, on such CPU, removed INT3 is still
> alive on the I-cache and hit it after text_poke_sync().
> This will be a ghost INT3...
An interrupt is a full memory barrier and it looks like qemu is not
honoring that. Thus the bug is in qemu and not the kernel.
-- Steve
prev parent reply other threads:[~2024-01-21 15:42 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-30 13:33 [PATCH -tip v2] x86/kprobes: Drop removed INT3 handling code Masami Hiramatsu (Google)
2023-01-07 11:36 ` [tip: perf/core] " tip-bot2 for Masami Hiramatsu (Google)
2024-01-20 17:44 ` [PATCH -tip v2] " Matthieu Baerts
2024-01-20 22:05 ` Steven Rostedt
2024-01-21 2:28 ` Masami Hiramatsu
2024-01-21 9:05 ` Masami Hiramatsu
2024-01-21 15:23 ` Matthieu Baerts
2024-01-21 15:31 ` Steven Rostedt
2024-01-21 15:33 ` Steven Rostedt
2024-01-21 16:20 ` Matthieu Baerts
2024-01-21 21:59 ` Matthieu Baerts
2024-01-22 1:17 ` Masami Hiramatsu
2024-01-21 15:42 ` Steven Rostedt [this message]
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