CVE-2026-64251

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

pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next()

pwrseq_debugfs_seq_next() declares 'next' with __free(put_device),

which causes put_device() to be called on the returned pointer when

the variable goes out of scope. This results in a use-after-free

since the seq_file framework receives a pointer whose reference has

already been dropped.

Simply removing __free(put_device) would fix the UAF but would leak

the reference acquired by bus_find_next_device(), as stop() only

calls up_read(&pwrseq_sem) and never releases the device reference.

Fix this by making the reference counting consistent across all

seq_file callbacks, matching the standard pattern used by PCI and

SCSI:

- start(): use get_device() so it returns a referenced pointer.

- next(): explicitly put_device(curr) to release the previous

device's reference (no NULL check needed - the seq_file framework

only calls next() while the previous return was non-NULL).

- stop(): put_device(data) to release the last iterated device's

reference, with a NULL guard since stop() may be called with NULL

when start() returned NULL or next() reached end-of-sequence.