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net/iucv: Avoid explicit cpumask var allocation on stack 

[ Upstream commit be4e1304419c99a164b4c0e101c7c2a756b635b9 ]

For CONFIG_CPUMASK_OFFSTACK=y kernel, explicit allocation of cpumask
variable on stack is not recommended since it can cause potential stack
overflow.

Instead, kernel code should always use *cpumask_var API(s) to allocate
cpumask var in config-neutral way, leaving allocation strategy to
CONFIG_CPUMASK_OFFSTACK.

Use *cpumask_var API(s) to address it.

Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Link: https://lore.kernel.org/r/20240331053441.1276826-2-dawei.li@shingroup.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Dawei Li 2024-03-31 13:34:40 +08:00 committed by Greg Kroah-Hartman
parent 8ac281d423
commit 724e7965af
1 changed files with 18 additions and 8 deletions
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26
net/iucv/iucv.c
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@ -519,7 +519,7 @@ static void iucv_setmask_mp(void)
*/
static void iucv_setmask_up(void)
{
cpumask_t cpumask;
static cpumask_t cpumask;
int cpu;
/* Disable all cpu but the first in cpu_irq_cpumask. */
@ -627,23 +627,33 @@ static int iucv_cpu_online(unsigned int cpu)
static int iucv_cpu_down_prep(unsigned int cpu)
{
cpumask_t cpumask;
cpumask_var_t cpumask;
int ret = 0;
if (!iucv_path_table)
return 0;
cpumask_copy(&cpumask, &iucv_buffer_cpumask);
cpumask_clear_cpu(cpu, &cpumask);
if (cpumask_empty(&cpumask))
if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
return -ENOMEM;
cpumask_copy(cpumask, &iucv_buffer_cpumask);
cpumask_clear_cpu(cpu, cpumask);
if (cpumask_empty(cpumask)) {
/* Can't offline last IUCV enabled cpu. */
return -EINVAL;
ret = -EINVAL;
goto __free_cpumask;
}
iucv_retrieve_cpu(NULL);
if (!cpumask_empty(&iucv_irq_cpumask))
return 0;
goto __free_cpumask;
smp_call_function_single(cpumask_first(&iucv_buffer_cpumask),
iucv_allow_cpu, NULL, 1);
return 0;
__free_cpumask:
free_cpumask_var(cpumask);
return ret;
}
/**