From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FB304CF49B; Sat, 17 Oct 2026 16:59:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792256353; cv=none; b=kz9HfCzE8aHBctjcDeTeYevfA+4tg1a73+NNc6O6j3LzFJDCEZnXp0XqI11p6ARqvrgqixGQAUXAc9o0uNCEYsU8+bbzBd4c4HMxsunbVEKKEVqjgsjZWXVL4sMneWBG2hBWvt2ma82IovNbi1H0e+XSIlTLNgvh4A92zI0o9/8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792256353; c=relaxed/simple; bh=BQsDfNtSHVeYY6gl6ENLa8NsYk5miO+7A5s4NFT3xV4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ESLavJA65J8ToVpi4ju9Y2sBbZSVXwz+wcKPm5VkeFIaRv+ziof+2y5FLT3OBy09ilvzgDaHn48xCsko9OClaTeZhDbNmsSVZ26fEXBlU/L0mX4JatPbu4ARA7jKBzXb5ZOf5WfyhqptmJPBC2QWxNdEUbkBa7FNZT2slHhAzW8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Cqtqw3sa; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Cqtqw3sa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9F921F000C4; Sat, 17 Oct 2026 16:59:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792256352; bh=9aA+SsF1BqJZTGUKlbnIh7yCp+NEIo9DCRu1iFvbryg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Cqtqw3sa2/OZd7cn16FYmvURsEM4oJ6+sohLOQFa4oVQNK3E8TyfbEjOcjCmXiYB2 BoNlmicuo9GO6f+3O9NcyZ+gjLm++YXUZ8tbglc9hVxf1a/f4te1bnFcJtFkHQngok wvI9vW7Zxl3kXVNoLHJi6CkBGARz6X+xcgnU9XxE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Leon Hwang , "Masami Hiramatsu (Google)" Subject: [PATCH 6.6 0166/1674] kprobes: Skip disarmed probes when checking optkprobe overlap Date: Sat, 17 Oct 2026 17:40:38 +0200 Message-ID: <20261017160435.422596430@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Leon Hwang commit 7a39c732a22ec4a369af9e19fbe3d666ec83eec4 upstream. On x86, an optkprobe at A replaces five bytes with a jump. If a disabled probe B is at A+2, get_optimized_kprobe() stops at B when arming a new probe C at A+4. It leaves A optimized: A A+1 A+2 A+3 A+4 A's jump | e9 | d0 | d1 | d2 | d3 | after C | e9 | d0 | d1 | d2 | cc | The INT3 for C overwrites the last byte of A's jump displacement, so execution can jump to the wrong address. B can have prepared optinsns while disarmed, but has no jump to unoptimize. Continue past disarmed and unprepared probes to find the active optimized probe before arming a probe in its jump. Link: https://lore.kernel.org/all/20260930053618.104498-1-leon.hwang@linux.dev/ Fixes: afd66255b9a4 ("kprobes: Introduce kprobes jump optimization") Cc: stable@vger.kernel.org Signed-off-by: Leon Hwang Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/kprobes.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -491,14 +491,16 @@ static bool kprobe_queued(struct kprobe static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr) { int i; - struct kprobe *p = NULL; + struct kprobe *p; struct optimized_kprobe *op; /* Don't check i == 0, since that is a breakpoint case. */ - for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++) + for (i = 1; i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++) { p = get_kprobe(addr - i); + /* A disabled probe can have prepared, but inactive, optinsns. */ + if (!p || !kprobe_optready(p) || kprobe_disarmed(p)) + continue; - if (p && kprobe_optready(p)) { op = container_of(p, struct optimized_kprobe, kp); if (arch_within_optimized_kprobe(op, addr)) return p;