From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B1D5D3B2321; Sat, 28 Feb 2026 17:38:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300312; cv=none; b=dMdrGw5HagTlmHC5IKtXO/NKJmGYE4ue0gNZjJRRmP+kP3BBy4Zmt/pOrT6e41ZzXhWxX1I1ApmyANZkLgJ9mIfqFCEjGeQLFIt44ZEqJ9T3VKI120PBps8lORWB3DD4bZle7WzoppFJop+RJSmJ+sOlsgcD+v/1XfpsoKfdbsE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300312; c=relaxed/simple; bh=FTnfptXU6GfqP6kpcpXunaUsnAH5Vacm9bOsUQdIZpo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ec9pohaNLusE2m3y6xywny4QlB1Tx4EqJqpzlQhf7dcHYeEE7E6dQAZvv5tCAGZn5oaT6n0/AOFTsma5xMg5nI1UdQf5fbt+XF75rKn2p3e8nVbo3yUxTWcyXiu45WZJ9lI4zJaXiVErR8EmyGgBpPr58osXL9mxULRVolz+N1Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ECx+igH+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ECx+igH+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0CB35C19423; Sat, 28 Feb 2026 17:38:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772300312; bh=FTnfptXU6GfqP6kpcpXunaUsnAH5Vacm9bOsUQdIZpo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ECx+igH+/J9EmzjLOWkOtitWu8Z9LBmBN/dMX/tRZvqVDPnNFfHzVpaP0Zejq13C/ FH1x2NhTd4X6iNG5EBWGqQ4mZNLFEBohJ7ZkeiFSxJwZ+agjmy481VMwwyYBJS/zSe 07UxG4aZwysF4YgOPyejE9DmS/L03Uiws7LgZrRZVpgQJrIFKqVSBnKYx4Z50Flrwv vtwXbmXF2ZrY+5eOHzryVxxCy8jdThE1jufTn1XB8r9bAujFqu2zqh0/I9j5xQtF4k dx+4q6hWaBkUG1+ynTY3ek4u+7LHlkUn5/VU92u/fwYixPxCluX3MkAx6JH4PzUgfV Z7eJFY0qMEdig== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tiwei Bie , Johannes Berg , Sasha Levin Subject: [PATCH 6.19 343/844] um: Preserve errno within signal handler Date: Sat, 28 Feb 2026 12:24:16 -0500 Message-ID: <20260228173244.1509663-344-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228173244.1509663-1-sashal@kernel.org> References: <20260228173244.1509663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Tiwei Bie [ Upstream commit f68b2d5a907b53eed99cf2efcaaae116df73c298 ] 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 Signed-off-by: Sasha Levin --- arch/um/os-Linux/signal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c index 327fb3c52fc79..de372b936a804 100644 --- a/arch/um/os-Linux/signal.c +++ b/arch/um/os-Linux/signal.c @@ -36,7 +36,6 @@ void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *, void *mc) = static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc) { struct uml_pt_regs r; - int save_errno = errno; r.is_user = 0; if (sig == SIGSEGV) { @@ -50,8 +49,6 @@ static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc) unblock_signals_trace(); (*sig_info[sig])(sig, si, &r, mc); - - errno = save_errno; } /* @@ -207,8 +204,11 @@ 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; (*handlers[sig])(sig, (struct siginfo *)si, mc); + + errno = save_errno; } void set_handler(int sig) -- 2.51.0