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Subject[PATCH 5.4 034/109] sched/core: Check cpus_mask, not cpus_ptr in __set_cpus_allowed_ptr(), to fix mask corruption
From: Scott Wood <>

[ Upstream commit fd844ba9ae59b51e34e77105d79f8eca780b3bd6 ]

This function is concerned with the long-term CPU mask, not the
transitory mask the task might have while migrate disabled. Before
this patch, if a task was migrate-disabled at the time
__set_cpus_allowed_ptr() was called, and the new mask happened to be
equal to the CPU that the task was running on, then the mask update
would be lost.

Signed-off-by: Scott Wood <>
Signed-off-by: Sebastian Andrzej Siewior <>
Signed-off-by: Peter Zijlstra (Intel) <>
Signed-off-by: Ingo Molnar <>
Signed-off-by: Sasha Levin <>
kernel/sched/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7238ef445dafb..8b3e99d095ae0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1649,7 +1649,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
goto out;

- if (cpumask_equal(p->cpus_ptr, new_mask))
+ if (cpumask_equal(&p->cpus_mask, new_mask))
goto out;

dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);

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