Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
fuse-uring: remove request-less entries from ent_w_req_queue to fix NULL deref
If a copy into the userspace ring buffer fails, a request will be terminated and fuse_uring_req_end() will set ent->fuse_req to NULL but it will leave the entry on ent_w_req_queue in FRRS_FUSE_REQ state. This can lead to a NULL deref if the request expiration logic scans ent_w_req_queue in the window before the entry is moved off it.
Fix this by taking the entry off ent_w_req_queue and changing its state from FRRS_FUSE_REQ to FRRS_INVALID before terminating the request.