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Fan WuandGreg Kroah-Hartman
0498b27a15
commit34c519feefupstream. The mtk_jpeg_release() function frees the context structure (ctx) without first cancelling any pending or running work in ctx->jpeg_work. This creates a race window where the workqueue callback may still be accessing the context memory after it has been freed. Race condition: CPU 0 (release) CPU 1 (workqueue) ---------------- ------------------ close() mtk_jpeg_release() mtk_jpegenc_worker() ctx = work->data // accessing ctx kfree(ctx) // freed! access ctx // UAF! The work is queued via queue_work() during JPEG encode/decode operations (via mtk_jpeg_device_run). If the device is closed while work is pending or running, the work handler will access freed memory. Fix this by calling cancel_work_sync() BEFORE acquiring the mutex. This ordering is critical: if cancel_work_sync() is called after mutex_lock(), and the work handler also tries to acquire the same mutex, it would cause a deadlock. Note: The open error path does NOT need cancel_work_sync() because INIT_WORK() only initializes the work structure - it does not schedule it. Work is only scheduled later during ioctl operations. Fixes:5fb1c2361e("mtk-jpegenc: add jpeg encode worker interface") Cc: stable@vger.kernel.org Signed-off-by: Fan Wu <fanwu01@zju.edu.cn> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>