CVE-2026-64251

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

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

pwrseqdebugfsseq_next() declares 'next' with _free(putdevice), which causes putdevice() to be called on the returned pointer when the variable goes out of scope. This results in a use-after-free since the seqfile framework receives a pointer whose reference has already been dropped.

Simply removing __free(putdevice) would fix the UAF but would leak the reference acquired by busfindnextdevice(), as stop() only calls upread(&pwrseqsem) 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 putdevice(curr) to release the previous device's reference (no NULL check needed - the seqfile 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.