From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793212490; b=zSwpkAANavJg1/sszpA0UfaNfau7TGRf/mfZUUoW9q6C4pgoo/LAG8KqVjHGkxyIMP3M u2c8yARLFG/TFYuzZFwkesvIk5LN8S3sINqzRwJNpLRk7RK4K+5vYfio/znui49fMvEEp H7jPLcuRo0kYMD2ShN6fpeSnRuEAlAwJdtPKYXxI5/ZZaS2Mid9AwLFdWy5jERTjgqqqe BEYMT52ubcQNC0S3VhU3ctRoMlPJbEOnTk68tzFN9qx45OnPcTHkALwKOMrnQdCRRV4KW +2U2UFnMtD/Unkw5Wgzjeca8hd0u0/LelKFCl0T4hwTi2mG5iVju0FemcGguEeZL45g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793212490; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=irwU2FV+8hI3eCGdMp2bdbtHmS+wt9h9yjXHjwgNaDA=; b=e1peR34cfHngmh/mmmZ9RzQe1oFpJ/KFm5CdbM3B5IiwToOCcx1HGqgNMHSkH4cPBLtm KxGl9Q3O+sf6lQz5kgxQCiL6voMGkMRQ9Mkdxh/eSsXFgBhAbudKyJ1m+tYAYDjGxbbu/ VgYJvzbPbix8qcsrEmEM8jTpclTf1D9hqkOcAxQqqa0xDLmDoVh0Cbb4ys41dAjj/lM2s BAP2q4SeuCY0vxZRYRYMOhSvd1eb0JY9Pmr/r4NlU0xntbAIJODSj1umg5sFugI19kH6r CppJcLwQJQTyW65fdLnX7dqO2Kt17JEDuEhrg4MynNN8RgtU7gd6u0gAleqcOO/f4HQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=srXxCzC2; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 113AD606A323; Wed, 28 Oct 2026 18:34:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=srXxCzC2 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 62CFD1F01825; Wed, 28 Oct 2026 18:34:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793212489; bh=irwU2FV+8hI3eCGdMp2bdbtHmS+wt9h9yjXHjwgNaDA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=srXxCzC2VDDHIrK4UBWtUNernToNBjEF1QyfEprigv2vhJUgXIw0vo9t8RfrWtobI Odh+K4ug9lrBKQBO4rCbxV4egh+256iQc19dlSpZbvT74FjjxxJjmMCJuXS/E9zBy5 EhOCKU9hwvl6ZIk9YJxCd8shV6OpE3MYOsL8uI/w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Leon Hwang , "Masami Hiramatsu (Google)" Subject: [PATCH 6.1 0173/1887] kprobes: Skip disarmed probes when checking optkprobe overlap Date: Wed, 28 Oct 2026 17:37:49 +0100 Message-ID: <20261028170503.175511582@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170459.200466217@linuxfoundation.org> References: <20261028170459.200466217@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-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;