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([101.76.249.46]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-38e174442f6sm2621595a91.10.2026.07.15.00.09.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2026 00:09:07 -0700 (PDT) From: Guangshuo Li To: Alexander Shishkin , Johan Hovold , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Cc: Guangshuo Li , stable@vger.kernel.org Subject: [PATCH v3] intel_th: fix MSC output device reference leak Date: Wed, 15 Jul 2026 15:08:51 +0800 Message-ID: <20260715070851.2077965-1-lgs201920130244@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit intel_th_output_open() looks up the output device with bus_find_device_by_devt(), which returns the device with a reference that must be dropped after use. commit 95fc36a234da ("intel_th: fix device leak on output open()") attempted to drop the reference from intel_th_output_release(). However, a successful open replaces file->f_op with the output driver file operations before returning, so close runs the output driver release callback instead. For MSC outputs, close runs intel_th_msc_release(), which only removes the per-file iterator and does not drop the device reference taken by intel_th_output_open(). Consequently, every successful MSC output open leaks one device reference. Drop the device reference from intel_th_msc_release(), which is the release path actually used for MSC output files. Remove the now-unused intel_th_output_release() callback from intel_th_output_fops. Fixes: 95fc36a234da ("intel_th: fix device leak on output open()") Cc: stable@vger.kernel.org Signed-off-by: Guangshuo Li --- v3: - Remove the unused intel_th_output_release() callback as suggested by Johan Hovold. v2: - Add Cc stable. - No code changes. drivers/hwtracing/intel_th/core.c | 10 ---------- drivers/hwtracing/intel_th/msu.c | 2 ++ 2 files changed, 2 insertions(+), 10 deletions(-) diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c index 3924e63e2eee..56acf31546da 100644 --- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -843,18 +843,8 @@ static int intel_th_output_open(struct inode *inode, struct file *file) return err; } -static int intel_th_output_release(struct inode *inode, struct file *file) -{ - struct intel_th_device *thdev = file->private_data; - - put_device(&thdev->dev); - - return 0; -} - static const struct file_operations intel_th_output_fops = { .open = intel_th_output_open, - .release = intel_th_output_release, .llseek = noop_llseek, }; diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c index a82cf74f39ad..84d99d7b1d20 100644 --- a/drivers/hwtracing/intel_th/msu.c +++ b/drivers/hwtracing/intel_th/msu.c @@ -1490,8 +1490,10 @@ static int intel_th_msc_release(struct inode *inode, struct file *file) { struct msc_iter *iter = file->private_data; struct msc *msc = iter->msc; + struct intel_th_device *thdev = msc->thdev; msc_iter_remove(iter, msc); + put_device(&thdev->dev); return 0; } -- 2.43.0