In the Linux kernel, the following vulnerability has been resolved: btrfs: don't stash io_uring...

In the Linux kernel, the following vulnerability has been resolved:

btrfs: don't stash io_uring encoded data across -EAGAIN

Returning -EAGAIN while leaving btrfs_uring_encoded_data in the cmd PDU leaks if the request is cancelled or the ring exits before reissue. io_uring does not free driver PDU allocations on cleanup.

Write: io_queue_sqe() always issues with IO_URING_F_NONBLOCK first, so return -EAGAIN before allocating and free data on every exit.

Read: free on nowait -EAGAIN too; only -EIOCBQUEUED keeps the allocation for btrfs_uring_read_finished().