{"id":24678,"date":"2026-09-16T20:32:38","date_gmt":"2026-09-16T12:32:38","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-89991"},"modified":"2026-09-16T20:32:38","modified_gmt":"2026-09-16T12:32:38","slug":"cve-2026-89991","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-89991","title":{"rendered":"CVE-2026-89991 &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix infinite loo"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>bpf: Fix infinite loop in pcpu_freelist push with one possible CPU<\/p>\n<p>__pcpu_freelist_push() can loop forever when only one CPU is possible<br \/>\nand an NMI re-enters pcpu_freelist_push() while the interrupted context<br \/>\nholds that CPU&#8217;s freelist lock.<\/p>\n<p>After the current-CPU fast path fails, the fallback loop walks<br \/>\ncpu_possible_mask while skipping the current CPU. With CONFIG_SMP=n, or<br \/>\nwhen an SMP kernel is limited to one possible CPU with nr_cpus=1 or<br \/>\npossible_cpus=1, there are no other possible CPUs to examine. The loop<br \/>\ntherefore makes no lock acquisition attempt and can never make progress.<\/p>\n<p>The following stack was observed on a UP system:<\/p>\n<p>  NMI context:<br \/>\n    pcpu_freelist_push<br \/>\n    free_htab_elem<br \/>\n    htab_map_delete_elem<br \/>\n    [perf-event BPF program]<br \/>\n    __perf_event_overflow<br \/>\n    perf_event_nmi_handler<br \/>\n    exc_nmi<\/p>\n<p>  Interrupted context:<br \/>\n    __pcpu_freelist_push<br \/>\n    pcpu_freelist_push<br \/>\n    free_htab_elem<br \/>\n    htab_map_delete_elem<br \/>\n    [raw_tp\/sys_enter BPF program]<br \/>\n    __bpf_trace_sys_enter<br \/>\n    do_syscall_64<\/p>\n<p>raw_res_spin_lock() detects the same-CPU recursive acquisition and<br \/>\nreturns -EDEADLK, but the subsequent fallback loop has no candidate head<br \/>\non a system with one possible CPU.<\/p>\n<p>Restore the extra fallback head that existed before the rqspinlock<br \/>\nconversion. Keep the current-CPU fast path, then try the other possible<br \/>\nCPUs and finally the extra head. The additional head lets a push, which<br \/>\ncannot fail without losing a preallocated element, make progress when the<br \/>\nonly per-CPU head is held by the interrupted context.<\/p>\n<p>Also check the extra head from the pop path so that nodes placed there<br \/>\ncan be reused.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>bpf: Fix infinite loop in pcpu_freelist push with one possible CPU<\/p>\n<p>__pcpu_freelist_push() can loop forever when only one CPU is po<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-24678","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/24678","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=24678"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=24678"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=24678"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}