6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gou Hao [ Upstream commit 411a3c016e7a95f5fa105a0587e07d0647a77727 ] When xive_init_ipis() fails (e.g. irq_domain_alloc_irqs() fails), the error path frees the global xive_ipis array. However, xive_smp_probe() previously ignored this failure and proceeded to call xive_setup_cpu_ipi(), which dereferences the already-freed xive_ipis pointer -- a use-after-free. Now that xive_smp_probe() returns int (previous patch), propagate the error from xive_init_ipis() and xive_setup_cpu_ipi() through xive_smp_probe(). Check the return value in both pnv_smp_probe() and pSeries_smp_probe() so that IPI setup is aborted cleanly on failure, avoiding the use-after-free. Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE interrupt controller") Fixes: cbc06f051c52 ("powerpc/xive: Do not skip CPU-less nodes when creating the IPIs") Signed-off-by: Gou Hao Reviewed-by: Wentao Guan Reviewed-by: jiazhenyuan Reviewed-by: Cédric Le Goater Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20260727104215.184786-4-gouhao@uniontech.com Signed-off-by: Sasha Levin --- arch/powerpc/platforms/powernv/smp.c | 8 +++++--- arch/powerpc/platforms/pseries/smp.c | 8 +++++--- arch/powerpc/sysdev/xive/common.c | 10 ++++++---- 3 files changed, 16 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c index 8f41ef364fc6f..b1201dbafcaf6 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -332,10 +332,12 @@ static void pnv_cause_ipi(int cpu) static void __init pnv_smp_probe(void) { - if (xive_enabled()) - xive_smp_probe(); - else + if (xive_enabled()) { + if (xive_smp_probe() < 0) + return; + } else { xics_smp_probe(); + } if (cpu_has_feature(CPU_FTR_DBELL)) { ic_cause_ipi = smp_ops->cause_ipi; diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c index db99725e752bd..14cd0634eeca8 100644 --- a/arch/powerpc/platforms/pseries/smp.c +++ b/arch/powerpc/platforms/pseries/smp.c @@ -194,10 +194,12 @@ static int pseries_cause_nmi_ipi(int cpu) static __init void pSeries_smp_probe(void) { - if (xive_enabled()) - xive_smp_probe(); - else + if (xive_enabled()) { + if (xive_smp_probe() < 0) + return; + } else { xics_smp_probe(); + } /* No doorbell facility, must use the interrupt controller for IPIs */ if (!cpu_has_feature(CPU_FTR_DBELL)) diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c index 92597aae4debc..b74cee368c044 100644 --- a/arch/powerpc/sysdev/xive/common.c +++ b/arch/powerpc/sysdev/xive/common.c @@ -1276,15 +1276,17 @@ noinstr static void xive_cleanup_cpu_ipi(unsigned int cpu, struct xive_cpu *xc) int __init xive_smp_probe(void) { + int ret; + smp_ops->cause_ipi = xive_cause_ipi; /* Register the IPI */ - xive_init_ipis(); + ret = xive_init_ipis(); + if (ret < 0) + return ret; /* Allocate and setup IPI for the boot CPU */ - xive_setup_cpu_ipi(smp_processor_id()); - - return 0; + return xive_setup_cpu_ipi(smp_processor_id()); } #endif /* CONFIG_SMP */ -- 2.53.0