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 00EAC38F626; Fri, 7 Aug 2026 14:43:04 +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=1786113804; cv=none; b=pHWg3QDA9F2bifjpbOg4tGUQ/FF0e83MSdxA2jSzIlxeeeh69ligcitVVxzEbe2wNvnM4JKP8LpIOkBy/lJrpXGDdild7BEhwOjjMAtnablJL0Wj9hBXLISUANhX+mz0sD5OsZ/sPYVuqgrk+ZGqjVHXPuyZ8GXSRweII7CQJqo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786113804; c=relaxed/simple; bh=1oFTqKUDaBnTjDYeLVWD0VxsgdObeq5QvdgxTfakQ8Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Fr9+RfBQFGqy/mt5XzJsq6bmqYm/TC0XvmXd78+L88ngqMWuugxIttKb10x8W35hJk8XFpGYl4ljkQNfe5e4Hw26GWwz6mYMtYUzJiTG4YQ7Y0qYZ/3b750VJqoGOqK5aFlNovdwiyUz6nRuEp8OabpVLgNu07l1kRGsE8QcnbE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zkpEN8ni; 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="zkpEN8ni" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A4741F00ACF; Fri, 7 Aug 2026 14:43:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786113782; bh=PwXVfWgDFrrZ7dgyDXGY+uY74TEn7tOaMNJuD5Ut0CI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=zkpEN8ni2c5ymBtRxlQGEN7a1iew9nj5P+bGBOHlYuSGHlx7PocQWK5L0FNfQ2xrg e+sxkbTtqYGKyNln40AcxNr0QdTBSk8/KT/wl/vAHdY76/ZEVsOitAGj6/5Iq48ULI 3kH8T3s5SfJqGN6n/uvMhgBQeuGHfbsIQwk6QzGk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tiwei Bie , Johannes Berg , Florian Fainelli , Sasha Levin Subject: [PATCH 6.12 010/337] um: Preserve errno within signal handler Date: Fri, 7 Aug 2026 16:33:33 +0200 Message-ID: <20260807143418.745439178@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143418.516897842@linuxfoundation.org> References: <20260807143418.516897842@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tiwei Bie commit f68b2d5a907b53eed99cf2efcaaae116df73c298 upstream. We rely on errno to determine whether a syscall has failed, so we need to ensure that accessing errno is async-signal-safe. Currently, we preserve the errno in sig_handler_common(), but it doesn't cover every possible case. Let's do it in hard_handler() instead, which is the signal handler we actually register. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20260106001228.1531146-2-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg [florian: hard_handler() in 6.12 retains the to_irq_stack/from_irq_stack loop from before the upstream SMP refactoring; errno save/restore is wrapped around that loop rather than replacing sig_handler_common's existing save/restore] Signed-off-by: Florian Fainelli Signed-off-by: Sasha Levin --- arch/um/os-Linux/signal.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c index b11ed66c8bb0..94abc9e3ec7e 100644 --- a/arch/um/os-Linux/signal.c +++ b/arch/um/os-Linux/signal.c @@ -190,6 +190,7 @@ static void hard_handler(int sig, siginfo_t *si, void *p) { ucontext_t *uc = p; mcontext_t *mc = &uc->uc_mcontext; + int save_errno = errno; unsigned long pending = 1UL << sig; do { @@ -227,6 +228,8 @@ static void hard_handler(int sig, siginfo_t *si, void *p) if (!nested) pending = from_irq_stack(nested); } while (pending); + + errno = save_errno; } void set_handler(int sig) -- 2.53.0