From patchwork Mon Dec 4 18:00:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Prarit Bhargava X-Patchwork-Id: 13478859 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FmdhiJ7r" Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8AD5FF for ; Mon, 4 Dec 2023 10:00:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701712847; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=S9ftojeH8GGZxU2oVCZDZDYHm92xZtIBjJ5gEF2G+Rc=; b=FmdhiJ7ri7erXiO1XfkXBbu0hn+47ghmQZFy2s29Oft//4hc+u3ruvUQp0NF9r0SzjgPr5 DFEtBxctxzAPDNtgE2yaeklyQEAM8VSYE2nEbJY5bWC71GOZ1SLNYam5fTDl0iIQ/Tgnel zqvIBt01eK3f/laQcqg9AaV1mu/L7yI= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-97-NcIh8DP8O3qx75jVIOIb1g-1; Mon, 04 Dec 2023 13:00:44 -0500 X-MC-Unique: NcIh8DP8O3qx75jVIOIb1g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6D0A138116E1; Mon, 4 Dec 2023 18:00:43 +0000 (UTC) Received: from prarit.bos.redhat.com (prarit2023-praritguest.khw1.lab.eng.bos.redhat.com [10.16.200.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3B2C1C1596F; Mon, 4 Dec 2023 18:00:43 +0000 (UTC) From: Prarit Bhargava To: linux-kernel@vger.kernel.org Cc: Prarit Bhargava , "Rafael J. Wysocki" , Len Brown , linux-acpi@vger.kernel.org Subject: [PATCH] ACPI: extlog fix null dereference check Date: Mon, 4 Dec 2023 13:00:37 -0500 Message-ID: <20231204180037.383583-1-prarit@redhat.com> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 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 dereference check in extlog_exit(). [1] https://gcc.gnu.org/onlinedocs/gcc-10.1.0/gcc/Static-Analyzer-Options.html CC: "Rafael J. Wysocki" CC: Len Brown CC: linux-acpi@vger.kernel.org Signed-off-by: Prarit Bhargava --- 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 e120a96e1eae..193147769146 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);