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authorDaniel Jordan <daniel.m.jordan@oracle.com>2020-04-21 12:34:55 -0400
committerHerbert Xu <herbert@gondor.apana.org.au>2020-04-30 15:19:33 +1000
commit3c2214b6027ff37945799de717c417212e1a8c54 (patch)
treea4fa09b5b3414a84465ab70f7fd525ce914a3bf9 /kernel/padata.c
parentb2d7e8bcaab7d1d931369984e2bae952247a1412 (diff)
padata: add separate cpuhp node for CPUHP_PADATA_DEAD
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 <daniel.m.jordan@oracle.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'kernel/padata.c')
-rw-r--r--kernel/padata.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/kernel/padata.c b/kernel/padata.c
index a6afa12fb75e..aae789896616 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -703,7 +703,7 @@ 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;
@@ -718,7 +718,7 @@ 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;
@@ -734,8 +734,9 @@ 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
WARN_ON(!list_empty(&pinst->pslist));
@@ -939,9 +940,10 @@ static struct padata_instance *padata_alloc(const char *name,
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
put_online_cpus();