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Thu, 22 Oct 2026 12:46:37 -0700 (PDT) Received: from casta ([42.116.198.195]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3ada49366fdsm5505889a91.14.2026.10.22.12.46.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Oct 2026 12:46:37 -0700 (PDT) From: Nguyen Duy Nhat Anh To: mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Nguyen Duy Nhat Anh Subject: [PATCH 0/3] media: em28xx: fix multiple disconnect races and UAFs Date: Fri, 23 Oct 2026 02:46:17 +0700 Message-ID: <20261022194618.14170-1-neganhat@gmail.com> X-Mailer: git-send-email 2.55.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This patch series addresses three distinct lifecycle and race condition bugs in the em28xx driver triggered during concurrent USB disconnect and userspace file operations (open/close). Fixing the initial refcount underflow (addressed in Patch 3/3) allowed syzbot re-testing to progress further down the teardown pipeline, which subsequently unveiled two deeper Use-After-Free (UAF) bugs in sequence (Patches 1/3 and 2/3). Summary of changes in the patches: 1. media: em28xx: check dev->disconnected in em28xx_v4l2_open() Rejects open() attempts with -ENODEV when the device is disconnected, preventing hardware register I/O on freed dev->intf memory. 2. media: em28xx: clear v4l2_dev.mdev on media device unregister Zeros out v4l2_dev.mdev in em28xx_unregister_media_device() before freeing dev->media_dev, avoiding a dangling pointer read in v4l2_release() during file close. 3. media: em28xx: fix refcount underflow in em28xx_free_v4l2() Removes v4l2_device_unregister() from the v4l2_dev release callback em28xx_free_v4l2() and invokes it in em28xx_v4l2_fini() instead, eliminating an illegal double-decrement on a zero reference count. Nguyen Duy Nhat Anh (3): media: em28xx: check dev->disconnected in em28xx_v4l2_open() media: em28xx: clear v4l2_dev.mdev on media device unregister media: em28xx: fix refcount underflow in em28xx_free_v4l2() drivers/media/usb/em28xx/em28xx-cards.c | 2 ++ drivers/media/usb/em28xx/em28xx-video.c | 5 ++--- 2 files changed, 4 insertions(+), 3 deletions(-) -- 2.55.0