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padata: validate cpumask without removed CPU during offline

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Configuring an instance's parallel mask without any online CPUs...

  echo 2 > /sys/kernel/pcrypt/pencrypt/parallel_cpumask
  echo 0 > /sys/devices/system/cpu/cpu1/online

...makes tcrypt mode=215 crash like this:

  divide error: 0000 [#1] SMP PTI
  CPU: 4 PID: 283 Comm: modprobe Not tainted 5.4.0-rc8-padata-doc-v2+ #2
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20191013_105130-anatol 04/01/2014
  RIP: 0010:padata_do_parallel+0x114/0x300
  Call Trace:
   pcrypt_aead_encrypt+0xc0/0xd0 [pcrypt]
   crypto_aead_encrypt+0x1f/0x30
   do_mult_aead_op+0x4e/0xdf [tcrypt]
   test_mb_aead_speed.constprop.0.cold+0x226/0x564 [tcrypt]
   do_test+0x28c2/0x4d49 [tcrypt]
   tcrypt_mod_init+0x55/0x1000 [tcrypt]
   ...

cpumask_weight() in padata_cpu_hash() returns 0 because the mask has no
CPUs.  The problem is __padata_remove_cpu() checks for valid masks too
early and so doesn't mark the instance PADATA_INVALID as expected, which
would have made padata_do_parallel() return error before doing the
division.

Fix by introducing a second padata CPU hotplug state before
CPUHP_BRINGUP_CPU so that __padata_remove_cpu() sees the online mask
without @cpu.  No need for the second argument to padata_replace() since
@cpu is now already missing from the online mask.

Fixes: 33e5445068 ("padata: Handle empty padata cpumasks")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Daniel Jordan 2019-12-03 14:31:10 -05:00 committed by Herbert Xu
parent e8cfed5e4e
commit 894c9ef978
2 changed files with 19 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/linux/cpuhotplug.h
View File

@ -59,6 +59,7 @@ enum cpuhp_state {
CPUHP_IOMMU_INTEL_DEAD,
CPUHP_LUSTRE_CFS_DEAD,
CPUHP_AP_ARM_CACHE_B15_RAC_DEAD,
CPUHP_PADATA_DEAD,
CPUHP_WORKQUEUE_PREP,
CPUHP_POWER_NUMA_PREPARE,
CPUHP_HRTIMERS_PREPARE,

30
kernel/padata.c
View File

@ -512,7 +512,7 @@ static int padata_replace_one(struct padata_shell *ps)
return 0;
}
static int padata_replace(struct padata_instance *pinst, int cpu)
static int padata_replace(struct padata_instance *pinst)
{
int notification_mask = 0;
struct padata_shell *ps;
@ -523,16 +523,12 @@ static int padata_replace(struct padata_instance *pinst, int cpu)
cpumask_copy(pinst->omask, pinst->rcpumask.pcpu);
cpumask_and(pinst->rcpumask.pcpu, pinst->cpumask.pcpu,
cpu_online_mask);
if (cpu >= 0)
cpumask_clear_cpu(cpu, pinst->rcpumask.pcpu);
if (!cpumask_equal(pinst->omask, pinst->rcpumask.pcpu))
notification_mask |= PADATA_CPU_PARALLEL;
cpumask_copy(pinst->omask, pinst->rcpumask.cbcpu);
cpumask_and(pinst->rcpumask.cbcpu, pinst->cpumask.cbcpu,
cpu_online_mask);
if (cpu >= 0)
cpumask_clear_cpu(cpu, pinst->rcpumask.cbcpu);
if (!cpumask_equal(pinst->omask, pinst->rcpumask.cbcpu))
notification_mask |= PADATA_CPU_SERIAL;
@ -624,7 +620,7 @@ static int __padata_set_cpumasks(struct padata_instance *pinst,
cpumask_copy(pinst->cpumask.pcpu, pcpumask);
cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst, -1);
err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst);
if (valid)
__padata_start(pinst);
@ -715,7 +711,7 @@ static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
int err = 0;
if (cpumask_test_cpu(cpu, cpu_online_mask)) {
err = padata_replace(pinst, -1);
err = padata_replace(pinst);
if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
@ -729,12 +725,12 @@ static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
{
int err = 0;
if (cpumask_test_cpu(cpu, cpu_online_mask)) {
if (!cpumask_test_cpu(cpu, cpu_online_mask)) {
if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
!padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
__padata_stop(pinst);
err = padata_replace(pinst, cpu);
err = padata_replace(pinst);
}
return err;
@ -761,7 +757,7 @@ static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
return ret;
}
static int padata_cpu_prep_down(unsigned int cpu, struct hlist_node *node)
static int padata_cpu_dead(unsigned int cpu, struct hlist_node *node)
{
struct padata_instance *pinst;
int ret;
@ -782,6 +778,7 @@ 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);
#endif
@ -989,6 +986,8 @@ static struct padata_instance *padata_alloc(const char *name,
#ifdef CONFIG_HOTPLUG_CPU
cpuhp_state_add_instance_nocalls_cpuslocked(hp_online, &pinst->node);
cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD,
&pinst->node);
#endif
put_online_cpus();
@ -1101,17 +1100,24 @@ static __init int padata_driver_init(void)
int ret;
ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
padata_cpu_online,
padata_cpu_prep_down);
padata_cpu_online, NULL);
if (ret < 0)
return ret;
hp_online = ret;
ret = cpuhp_setup_state_multi(CPUHP_PADATA_DEAD, "padata:dead",
NULL, padata_cpu_dead);
if (ret < 0) {
cpuhp_remove_multi_state(hp_online);
return ret;
}
return 0;
}
module_init(padata_driver_init);
static __exit void padata_driver_exit(void)
{
cpuhp_remove_multi_state(CPUHP_PADATA_DEAD);
cpuhp_remove_multi_state(hp_online);
}
module_exit(padata_driver_exit);