From 93175d935d76f4a7220fe9111ba452bb5c512fa4 Mon Sep 17 00:00:00 2001 From: Daniel Jordan Date: Tue, 21 Apr 2020 12:34:55 -0400 Subject: [PATCH] padata: add separate cpuhp node for CPUHP_PADATA_DEAD commit 3c2214b6027ff37945799de717c417212e1a8c54 upstream. Removing the pcrypt module triggers this: general protection fault, probably for non-canonical address 0xdead000000000122 CPU: 5 PID: 264 Comm: modprobe Not tainted 5.6.0+ #2 Hardware name: QEMU Standard PC RIP: 0010:__cpuhp_state_remove_instance+0xcc/0x120 Call Trace: padata_sysfs_release+0x74/0xce kobject_put+0x81/0xd0 padata_free+0x12/0x20 pcrypt_exit+0x43/0x8ee [pcrypt] padata instances wrongly use the same hlist node for the online and dead states, so __padata_free()'s second cpuhp remove call chokes on the node that the first poisoned. cpuhp multi-instance callbacks only walk forward in cpuhp_step->list and the same node is linked in both the online and dead lists, so the list corruption that results from padata_alloc() adding the node to a second list without removing it from the first doesn't cause problems as long as no instances are freed. Avoid the issue by giving each state its own node. Fixes: 894c9ef9780c ("padata: validate cpumask without removed CPU during offline") Signed-off-by: Daniel Jordan Cc: Herbert Xu Cc: Steffen Klassert Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Herbert Xu Signed-off-by: Yang Yingliang Signed-off-by: Greg Kroah-Hartman --- include/linux/padata.h | 6 ++++-- kernel/padata.c | 14 ++++++++------ 2 files changed, 12 insertions(+), 8 deletions(-) diff --git a/include/linux/padata.h b/include/linux/padata.h index d803397a28f7..8c9827cc6374 100644 --- a/include/linux/padata.h +++ b/include/linux/padata.h @@ -138,7 +138,8 @@ struct parallel_data { /** * struct padata_instance - The overall control structure. * - * @cpu_notifier: cpu hotplug notifier. + * @cpu_online_node: Linkage for CPU online callback. + * @cpu_dead_node: Linkage for CPU offline callback. * @wq: The workqueue in use. * @pd: The internal control structure. * @cpumask: User supplied cpumasks for parallel and serial works. @@ -150,7 +151,8 @@ struct parallel_data { * @flags: padata flags. */ struct padata_instance { - struct hlist_node node; + struct hlist_node cpu_online_node; + struct hlist_node cpu_dead_node; struct workqueue_struct *wq; struct parallel_data *pd; struct padata_cpumask cpumask; diff --git a/kernel/padata.c b/kernel/padata.c index 4401b4f13d0b..7f2b6d369fd4 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -748,7 +748,7 @@ static int padata_cpu_online(unsigned int cpu, struct hlist_node *node) struct padata_instance *pinst; int ret; - pinst = hlist_entry_safe(node, struct padata_instance, node); + pinst = hlist_entry_safe(node, struct padata_instance, cpu_online_node); if (!pinst_has_cpu(pinst, cpu)) return 0; @@ -763,7 +763,7 @@ static int padata_cpu_dead(unsigned int cpu, struct hlist_node *node) struct padata_instance *pinst; int ret; - pinst = hlist_entry_safe(node, struct padata_instance, node); + pinst = hlist_entry_safe(node, struct padata_instance, cpu_dead_node); if (!pinst_has_cpu(pinst, cpu)) return 0; @@ -779,8 +779,9 @@ static enum cpuhp_state hp_online; static void __padata_free(struct padata_instance *pinst) { #ifdef CONFIG_HOTPLUG_CPU - cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD, &pinst->node); - cpuhp_state_remove_instance_nocalls(hp_online, &pinst->node); + cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD, + &pinst->cpu_dead_node); + cpuhp_state_remove_instance_nocalls(hp_online, &pinst->cpu_online_node); #endif padata_stop(pinst); @@ -964,9 +965,10 @@ static struct padata_instance *padata_alloc(struct workqueue_struct *wq, mutex_init(&pinst->lock); #ifdef CONFIG_HOTPLUG_CPU - cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node); + cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, + &pinst->cpu_online_node); cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD, - &pinst->node); + &pinst->cpu_dead_node); #endif return pinst;