CVE-2026-64415mm/swap: add cond_resched() in swap_reclaim_full_clusters to prevent softlockup

Official description

In the Linux kernel, the following vulnerability has been resolved: mm/swap: add cond_resched() in swap_reclaim_full_clusters to prevent softlockup We hit a real softlockup in an internal stress test environment. The workload was LTP memory/swap stress on a large arm64 machine, with 320 CPUs, about 1TB memory and an 8.6GB swap device. The system was under heavy load and the swap device had a large number of full clusters. The softlockup was triggered during a stress test after about 3 days. So, add periodic cond_resched() calls during large full_clusters reclaim operations to prevent softlockup issues. Detailed call trace as follow: PID: 3817773 TASK: ffff0883bb28b780 CPU: 48 COMMAND: "kworker/48:7" #0 [ffff800080183d10] __crash_kexec at ffffa4c1361e5de4 #1 [ffff800080183d90] panic at ffffa4c1360d5e9c #2 [ffff800080183e20] watchdog_timer_fn at ffffa4c136231fa8 ... #16 [ffff8000c4ad3cb0] swap_cache_del_folio at ffffa4c1363e1614 #17 [ffff8000c4ad3ce0] __try_to_reclaim_swap at ffffa4c1363e4bfc #18 [ffff8000c4ad3d40] swap_reclaim_full_clusters at ffffa4c1363e5474 #19 [ffff8000c4ad3da0] swap_reclaim_work at ffffa4c1363e550c #20 [ffff8000c4ad3dc0] process_one_work at ffffa4c136102edc #21 [ffff8000c4ad3e10] worker_thread at ffffa4c136103398 #22 [ffff8000c4ad3e70] kthread at ffffa4c13610d95c

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/60cbe67d1342f34b66df1c2ee328e3cd333767d7
• https://git.kernel.org/stable/c/69c0e6246575b780ae0d3f411c749bcf13c221f3
• https://git.kernel.org/stable/c/2a55fdf9f746a1a6ced7fd62ea1080b8a917e0b0
• https://git.kernel.org/stable/c/66366d291f666ddeda5f8c84f253e308de3e6b55