CVE-2026-90043zram: fix slot lock bit position on big-endian 64-bit

Official description

In the Linux kernel, the following vulnerability has been resolved: zram: fix slot lock bit position on big-endian 64-bit The slot lock is a bit operation on the whole __lock word, which flags and ac_time alias as two u32s. On little-endian the lock bit lands in the position ZRAM_ENTRY_LOCK reserves in flags, so the aliasing works out. On 64-bit big-endian it lands in ac_time instead: with ZRAM_TRACK_ENTRY_ACTIME enabled, storing the access time from mark_slot_accessed() or slot_free() wipes out the held lock bit, letting another CPU take the same slot lock; an access time value with that bit set makes the slot look locked forever. Shift the lock bit into the flags half of the word on big-endian 64-bit.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/052b6b2d5fe97547bd2cdb73fa894f6cfea68b11
• https://git.kernel.org/stable/c/a8b5875741d416703e19ad8eeac6fce8a12bd6e4