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 4383E24A1C; Tue, 16 Jan 2024 00:15:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Q+oG9YC/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55370C433F1; Tue, 16 Jan 2024 00:15:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1705364107; bh=D59vzrAcr4nIu1QBsM1dhuamAXH77x0gI+kpEJaIURY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q+oG9YC/ITvVv9TpeuBSBHWC8aDB3QW71sepaY46sRONgpzDAqQP00oCQwBGfkcQB qPuChYOI8XbJ76gTGYPNKtIXmE3pc5CYjiGXHeGOzDuOt8itOOlBUZ6hxuSPMd8GMh 0sapsaIEaQlztaJUtvraQtPnbTzFNkdkRAdabvO3raXoeI8l9ZD/y9nEXL/gFpLNhJ b3JPcQgxbSRiBc9zB99zdI7aXgKlqJJ/8o6sDEnIkD9Y14qiftmuHDkOxTjgaS3h4Q YCm4iy+WE6ZDzZhg8nkifkFaE8e4xaeP/Y0/LalXIBrsxcOYEa0fMk2tQvmTlaZ4Kp 50iXkTCSJKxtw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Prarit Bhargava , "Rafael J . Wysocki" , Sasha Levin , rafael@kernel.org, linux-acpi@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 6/8] ACPI: extlog: fix NULL pointer dereference check Date: Mon, 15 Jan 2024 19:14:52 -0500 Message-ID: <20240116001457.214018-6-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240116001457.214018-1-sashal@kernel.org> References: <20240116001457.214018-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.208 Content-Transfer-Encoding: 8bit From: Prarit Bhargava [ Upstream commit 72d9b9747e78979510e9aafdd32eb99c7aa30dd1 ] The gcc plugin -fanalyzer [1] tries to detect various patterns of incorrect behaviour. The tool reports: drivers/acpi/acpi_extlog.c: In function ‘extlog_exit’: drivers/acpi/acpi_extlog.c:307:12: warning: check of ‘extlog_l1_addr’ for NULL after already dereferencing it [-Wanalyzer-deref-before-check] | | 306 | ((struct extlog_l1_head *)extlog_l1_addr)->flags &= ~FLAG_OS_OPTIN; | | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~ | | | | | (1) pointer ‘extlog_l1_addr’ is dereferenced here | 307 | if (extlog_l1_addr) | | ~ | | | | | (2) pointer ‘extlog_l1_addr’ is checked for NULL here but it was already dereferenced at (1) | Fix the NULL pointer dereference check in extlog_exit(). Link: https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Static-Analyzer-Options.html # [1] Signed-off-by: Prarit Bhargava Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/acpi/acpi_extlog.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c index e648158368a7..ac89bc85a9c9 100644 --- a/drivers/acpi/acpi_extlog.c +++ b/drivers/acpi/acpi_extlog.c @@ -303,9 +303,10 @@ static int __init extlog_init(void) static void __exit extlog_exit(void) { mce_unregister_decode_chain(&extlog_mce_dec); - ((struct extlog_l1_head *)extlog_l1_addr)->flags &= ~FLAG_OS_OPTIN; - if (extlog_l1_addr) + if (extlog_l1_addr) { + ((struct extlog_l1_head *)extlog_l1_addr)->flags &= ~FLAG_OS_OPTIN; acpi_os_unmap_iomem(extlog_l1_addr, l1_size); + } if (elog_addr) acpi_os_unmap_iomem(elog_addr, elog_size); release_mem_region(elog_base, elog_size); -- 2.43.0