{"schema":"threatline.record/2","record":{"id":"CVE-2026-98395","aliases":[],"summary":"powerpc/entry: Fix irq_soft_mask corruption on replayed interrupt exit","details":"In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/entry: Fix irq_soft_mask corruption on replayed interrupt exit\n\nWhen __replay_soft_interrupts() replays a pending interrupt (e.g.\nPACA_IRQ_DEC -> timer_interrupt), it calls the handler directly with a\nsynthetic pt_regs. The DEFINE_INTERRUPT_HANDLER_ASYNC wrapper around\neach handler calls arch_interrupt_async_exit_prepare() on the way out,\nwhich calls arch_interrupt_exit_prepare() -> local_irq_disable() ->\narch_local_irq_disable(), which does:\n\n    irq_soft_mask_set(IRQS_DISABLED)   /* 0x1 */\n\nThis unconditionally overwrites irq_soft_mask with IRQS_DISABLED (0x1),\nstripping the IRQS_PMI_DISABLED (0x2) bit. The result is that\nirq_soft_mask is 0x1 instead of IRQS_ALL_DISABLED (0x3) when the\nhandler returns to __replay_soft_interrupts().\n\nFor a normally-taken interrupt this is harmless: the next interrupt\nalways enters through arch_interrupt_enter_prepare() which\nunconditionally sets irq_soft_mask to IRQS_ALL_DISABLED. But during\nreplay, next_interrupt() is called directly between replayed handlers\nwithout going back through arch_interrupt_enter_prepare(), so the\nstripped bit is never restored. next_interrupt() then fires a WARNING:\n\n    WARNING: arch/powerpc/kernel/irq_64.c:75\n    WARN_ON(irq_soft_mask_return() != IRQS_ALL_DISABLED)\n\nThe warning was observed early in boot on a POWER10 pseries guest\nduring kmem_cache_init_late(), where a spinlock release triggers\ninterrupt replay that processes a pending timer interrupt.\n\nDebugger state confirming the bug:\n  Before timer_interrupt(&regs):\n    irq_soft_mask = 0x3 (IRQS_ALL_DISABLED)   correct\n    irq_happened  = 0x41 (HARD_DIS|REPLAYING)  correct\n  After timer_interrupt(&regs) returns:\n    irq_soft_mask = 0x1 (IRQS_DISABLED)        WRONG - PMI bit stripped\n    irq_happened  = 0x41                        unchanged\n\nThe fix is to replace local_irq_disable() with hard_irq_disable().\n\nhard_irq_disable() is the right primitive here for two reasons:\n\n1. On PPC64 (hw_irq.h:301) it calls irq_soft_mask_set_return(IRQS_ALL_DISABLED),\n   setting the soft mask to 0x3 (both IRQS_DISABLED and IRQS_PMI_DISABLED),\n   which preserves the PMI bit and fixes the WARNING. The additional\n   work it does (__hard_irq_disable(), PACA_IRQ_HARD_DIS |=) is\n   redundant but safe since both are already set at this point in the\n   exit path; the trace_hardirqs_off() inside is guarded by\n   if (!arch_irqs_disabled_flags(flags)) so it will not double-fire.\n\n2. On PPC32 (hw_irq.h:467) hard_irq_disable() maps to\n   arch_local_irq_disable() -> __hard_irq_disable(), which clears\n   MSR[EE] in hardware. This is exactly correct: PPC32 has no soft-mask\n   PACA mechanism, so the hardware disable is the right way to satisfy\n   irqentry_exit()'s requirement. This also fixes a build error on PPC32\n   where irq_soft_mask_set() is only defined under CONFIG_PPC64:\n\n       arch/powerpc/include/asm/entry-common.h:273: error: implicit\n       declaration of function 'irq_soft_mask_set'\n\n   Using hard_irq_disable() requires no #ifdef and is consistent with\n   how the rest of the entry code (e.g. entry-common.h:463) handles the\n   same PPC32/PPC64 split.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98395","source_modified_at":"2026-10-19T09:18:48.849Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"334f3f6d7a1660fd65597bad9960bfa33a716d35","lessThan":"95cd316a896f1c1aa4ee4a817ba3d4691103c81b","status":"affected","versionType":"git"},{"version":"334f3f6d7a1660fd65597bad9960bfa33a716d35","lessThan":"63a7531ca31f9f097d9cc1cc3fe86ae683cdabdd","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98395","source_modified_at":"2026-10-19T09:18:48.849Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"7.2","status":"affected"},{"version":"0","lessThan":"7.2","status":"unaffected","versionType":"semver"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98395","source_modified_at":"2026-10-19T09:18:48.849Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"95cd316a896f1c1aa4ee4a817ba3d4691103c81b","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98395","source_modified_at":"2026-10-19T09:18:48.849Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"63a7531ca31f9f097d9cc1cc3fe86ae683cdabdd","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00198,"percentile":0.0902,"score_date":"2026-10-23"},"published_at":"2026-10-14T13:25:57.887Z","modified_at":"2026-10-19T09:18:48.849Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98395","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:18:48.849Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98395","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/95cd316a896f1c1aa4ee4a817ba3d4691103c81b"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/63a7531ca31f9f097d9cc1cc3fe86ae683cdabdd"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:18:48.849Z","content_hash":"d0e20e2f77f8b2af4db5d070cb0d99f57b2ede6ce798efb1d9f01bd8d3291f34"}}