Re: [PATCH v6 11/21] sched: Split the guts of sched_setaffinity() into a helper function

On Fri, May 21, 2021 at 05:41:01PM +0100, Qais Yousef wrote:

On 05/18/21 10:47, Will Deacon wrote:

quoted

In preparation for replaying user affinity requests using a saved mask,
split sched_setaffinity() up so that the initial task lookup and
security checks are only performed when the request is coming directly
from userspace.

Signed-off-by: Will Deacon <will@kernel.org>
---
 kernel/sched/core.c | 110 +++++++++++++++++++++++---------------------
 1 file changed, 58 insertions(+), 52 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9512623d5a60..808bbe669a6d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c

@@ -6788,9 +6788,61 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
 	return retval;
 }
 
-long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+static int
+__sched_setaffinity(struct task_struct *p, const struct cpumask *mask)
 {
+	int retval;
 	cpumask_var_t cpus_allowed, new_mask;
+
+	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL))
+		return -ENOMEM;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+		return -ENOMEM;

Shouldn't we free cpus_allowed first?

Oops, yes. Now fixed.

Thanks,

Will

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