From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.smtp-ext.broadcom.com (relay.smtp-ext.broadcom.com [192.19.144.205]) (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 B48D73C1400; Fri, 24 Jul 2026 21:41:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.19.144.205 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784929291; cv=none; b=WwLcwKkWFDPM3pOw6j2Gfj9C1jzpM2OKIIKnaIWssaANzu0o/46bFWzVd2p4idzkaZIpOvm+s1FMKCMaVH0q5Je9PmvJd3nloFjpA7AGip7Io3rFASckgZNaEmtJSVDfi5oQcW7iuAmxldRBmoRiuryaw+Q5oYst/tkwyeZqjNM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784929291; c=relaxed/simple; bh=a0Cfg7X+g3S2j3WgmrnppIxwpz2k3rDILWehus98x28=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ujlQKVu6xvQ8BBGDtHBb8KWUmgfu5cTjk+IvyfQZYH+cQGhbhTtsdOfdbfRMgXE/rk3IGNAUt/B8ks2C2QpIJHEpeRy51KHCe3rEIJaCbK+3yZ7tZ7re+qgHdtxEpr95hYIy0Sq+wDvbu8ANJ/HvsAo3PBzNir/djvJDimPD6Uk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=broadcom.com; spf=fail smtp.mailfrom=broadcom.com; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b=RF0dO4fx; arc=none smtp.client-ip=192.19.144.205 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=broadcom.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=broadcom.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="RF0dO4fx" Received: from mail-lvn-it-01.broadcom.com (mail-lvn-it-01.lvn.broadcom.net [10.36.132.253]) by relay.smtp-ext.broadcom.com (Postfix) with ESMTP id 8403DC0000FC; Fri, 24 Jul 2026 14:41:23 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 relay.smtp-ext.broadcom.com 8403DC0000FC DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=broadcom.com; s=dkimrelay; t=1784929283; bh=a0Cfg7X+g3S2j3WgmrnppIxwpz2k3rDILWehus98x28=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RF0dO4fxr+fXUcerTBF4BDXI8aar+8stV5nFdcqIKg5cJqwA3wvps+YdMx+XQv74x Z1JTdJw2EXCfq7Sp20J8hQlWwLzttFUpiPsFcp+BfGhXnD007X+1FiCI4SazOx6an/ tcaFJRy70sO2JuWSkcM0aU1kPKWdSg7c2EiILzTs= Received: from stbirv-lnx-1.igp.broadcom.net (stbirv-lnx-1.igp.broadcom.net [10.67.48.32]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail-lvn-it-01.broadcom.com (Postfix) with ESMTPSA id 14C66ACE; Fri, 24 Jul 2026 14:41:23 -0700 (PDT) From: Florian Fainelli To: stable@vger.kernel.org Cc: Tiwei Bie , Johannes Berg , Florian Fainelli , Richard Weinberger , Anton Ivanov , Johannes Berg , Brendan Higgins , David Gow , Rae Moar , Kees Cook , Jens Axboe , Al Viro , linux-um@lists.infradead.org (open list:USER-MODE LINUX (UML)), linux-kernel@vger.kernel.org (open list), linux-kselftest@vger.kernel.org (open list:KERNEL UNIT TESTING FRAMEWORK (KUnit)), kunit-dev@googlegroups.com (open list:KERNEL UNIT TESTING FRAMEWORK (KUnit)), bcm-kernel-feedback-list@broadcom.com Subject: [PATCH stable 6.12 9/9] um: Preserve errno within signal handler Date: Fri, 24 Jul 2026 14:41:19 -0700 Message-Id: <20260724214119.1066665-10-florian.fainelli@broadcom.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260724214119.1066665-1-florian.fainelli@broadcom.com> References: <20260724214119.1066665-1-florian.fainelli@broadcom.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- 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) -- 2.34.1