From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 4.19 44/83] acpi/nfit: Fix race accessing memdev in nfit_get_smbios_id() Date: Tue, 12 Feb 2019 21:36:22 -0500 Message-ID: <20190213023701.20286-44-sashal@kernel.org> References: <20190213023701.20286-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190213023701.20286-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Tony Luck , Dan Williams , Sasha Levin , linux-nvdimm@lists.01.org, linux-acpi@vger.kernel.org List-Id: linux-acpi@vger.kernel.org From: Tony Luck [ Upstream commit 0919871ac37fdcf46c7657da0f1742efe096b399 ] Possible race accessing memdev structures after dropping the mutex. Dan Williams says this could race against another thread that is doing: # echo "ACPI0012:00" > /sys/bus/acpi/drivers/nfit/unbind Reported-by: Jane Chu Fixes: 23222f8f8dce ("acpi, nfit: Add function to look up nvdimm...") Signed-off-by: Tony Luck Signed-off-by: Dan Williams Signed-off-by: Sasha Levin --- drivers/acpi/nfit/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index ea59c01ce8db..f530d3541242 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -719,6 +719,7 @@ int nfit_get_smbios_id(u32 device_handle, u16 *flags) struct acpi_nfit_memory_map *memdev; struct acpi_nfit_desc *acpi_desc; struct nfit_mem *nfit_mem; + u16 physical_id; mutex_lock(&acpi_desc_lock); list_for_each_entry(acpi_desc, &acpi_descs, list) { @@ -726,10 +727,11 @@ int nfit_get_smbios_id(u32 device_handle, u16 *flags) list_for_each_entry(nfit_mem, &acpi_desc->dimms, list) { memdev = __to_nfit_memdev(nfit_mem); if (memdev->device_handle == device_handle) { + *flags = memdev->flags; + physical_id = memdev->physical_id; mutex_unlock(&acpi_desc->init_mutex); mutex_unlock(&acpi_desc_lock); - *flags = memdev->flags; - return memdev->physical_id; + return physical_id; } } mutex_unlock(&acpi_desc->init_mutex); -- 2.19.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id EF6D9202E53A7 for ; Tue, 12 Feb 2019 18:38:16 -0800 (PST) From: Sasha Levin Subject: [PATCH AUTOSEL 4.19 44/83] acpi/nfit: Fix race accessing memdev in nfit_get_smbios_id() Date: Tue, 12 Feb 2019 21:36:22 -0500 Message-Id: <20190213023701.20286-44-sashal@kernel.org> In-Reply-To: <20190213023701.20286-1-sashal@kernel.org> References: <20190213023701.20286-1-sashal@kernel.org> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sasha Levin , linux-acpi@vger.kernel.org, Tony Luck , linux-nvdimm@lists.01.org List-ID: From: Tony Luck [ Upstream commit 0919871ac37fdcf46c7657da0f1742efe096b399 ] Possible race accessing memdev structures after dropping the mutex. Dan Williams says this could race against another thread that is doing: # echo "ACPI0012:00" > /sys/bus/acpi/drivers/nfit/unbind Reported-by: Jane Chu Fixes: 23222f8f8dce ("acpi, nfit: Add function to look up nvdimm...") Signed-off-by: Tony Luck Signed-off-by: Dan Williams Signed-off-by: Sasha Levin --- drivers/acpi/nfit/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index ea59c01ce8db..f530d3541242 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -719,6 +719,7 @@ int nfit_get_smbios_id(u32 device_handle, u16 *flags) struct acpi_nfit_memory_map *memdev; struct acpi_nfit_desc *acpi_desc; struct nfit_mem *nfit_mem; + u16 physical_id; mutex_lock(&acpi_desc_lock); list_for_each_entry(acpi_desc, &acpi_descs, list) { @@ -726,10 +727,11 @@ int nfit_get_smbios_id(u32 device_handle, u16 *flags) list_for_each_entry(nfit_mem, &acpi_desc->dimms, list) { memdev = __to_nfit_memdev(nfit_mem); if (memdev->device_handle == device_handle) { + *flags = memdev->flags; + physical_id = memdev->physical_id; mutex_unlock(&acpi_desc->init_mutex); mutex_unlock(&acpi_desc_lock); - *flags = memdev->flags; - return memdev->physical_id; + return physical_id; } } mutex_unlock(&acpi_desc->init_mutex); -- 2.19.1 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm