{"id":"CVE-2026-43326","summary":"sched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback\n\nSCX_KICK_WAIT busy-waits in kick_cpus_irq_workfn() using\nsmp_cond_load_acquire() until the target CPU's kick_sync advances. Because\nthe irq_work runs in hardirq context, the waiting CPU cannot reschedule and\nits own kick_sync never advances. If multiple CPUs form a wait cycle, all\nCPUs deadlock.\n\nReplace the busy-wait in kick_cpus_irq_workfn() with resched_curr() to\nforce the CPU through do_pick_task_scx(), which queues a balance callback\nto perform the wait. The balance callback drops the rq lock and enables\nIRQs following the sched_core_balance() pattern, so the CPU can process\nIPIs while waiting. The local CPU's kick_sync is advanced on entry to\ndo_pick_task_scx() and continuously during the wait, ensuring any CPU that\nstarts waiting for us sees the advancement and cannot form cyclic\ndependencies.","modified":"2026-07-08T08:13:28.154890876Z","published":"2026-05-08T13:31:10.184Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43326.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/415cb193bb9736f0e830286c72a6fa8eb2a9cc5c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c3a7903f65cf4c7fb0477eb0f8b94f326a47fe54"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43326.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43326"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"90e55164dad42c6546b698c031697b224a320834"},{"fixed":"c3a7903f65cf4c7fb0477eb0f8b94f326a47fe54"},{"fixed":"415cb193bb9736f0e830286c72a6fa8eb2a9cc5c"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43326.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.19.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43326.json"}}],"schema_version":"1.7.5"}