From: "tip-bot2 for Will Deacon" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Will Deacon <will@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Valentin Schneider <Valentin.Schneider@arm.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: sched/core] sched: Split the guts of sched_setaffinity() into a helper function
Date: Mon, 23 Aug 2021 09:26:21 -0000 [thread overview]
Message-ID: <162971078114.25758.18226375114589760498.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210730112443.23245-8-will@kernel.org>
The following commit has been merged into the sched/core branch of tip:
Commit-ID: db3b02ae896e88b6bb7a95c1373602e87e0de84c
Gitweb: https://git.kernel.org/tip/db3b02ae896e88b6bb7a95c1373602e87e0de84c
Author: Will Deacon <will@kernel.org>
AuthorDate: Fri, 30 Jul 2021 12:24:34 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 20 Aug 2021 12:33:00 +02:00
sched: Split the guts of sched_setaffinity() into a helper function
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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <Valentin.Schneider@arm.com>
Link: https://lore.kernel.org/r/20210730112443.23245-8-will@kernel.org
---
kernel/sched/core.c | 105 +++++++++++++++++++++++--------------------
1 file changed, 57 insertions(+), 48 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 360a3ec..672d0fc 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7594,53 +7594,22 @@ out_unlock:
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)
{
- cpumask_var_t cpus_allowed, new_mask;
- struct task_struct *p;
int retval;
+ cpumask_var_t cpus_allowed, new_mask;
- rcu_read_lock();
-
- p = find_process_by_pid(pid);
- if (!p) {
- rcu_read_unlock();
- return -ESRCH;
- }
-
- /* Prevent p going away */
- get_task_struct(p);
- rcu_read_unlock();
+ if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL))
+ return -ENOMEM;
- if (p->flags & PF_NO_SETAFFINITY) {
- retval = -EINVAL;
- goto out_put_task;
- }
- if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
- retval = -ENOMEM;
- goto out_put_task;
- }
if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
retval = -ENOMEM;
goto out_free_cpus_allowed;
}
- retval = -EPERM;
- if (!check_same_owner(p)) {
- rcu_read_lock();
- if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
- rcu_read_unlock();
- goto out_free_new_mask;
- }
- rcu_read_unlock();
- }
-
- retval = security_task_setscheduler(p);
- if (retval)
- goto out_free_new_mask;
-
cpuset_cpus_allowed(p, cpus_allowed);
- cpumask_and(new_mask, in_mask, cpus_allowed);
+ cpumask_and(new_mask, mask, cpus_allowed);
/*
* Since bandwidth control happens on root_domain basis,
@@ -7661,23 +7630,63 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
#endif
again:
retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK);
+ if (retval)
+ goto out_free_new_mask;
- if (!retval) {
- cpuset_cpus_allowed(p, cpus_allowed);
- if (!cpumask_subset(new_mask, cpus_allowed)) {
- /*
- * We must have raced with a concurrent cpuset
- * update. Just reset the cpus_allowed to the
- * cpuset's cpus_allowed
- */
- cpumask_copy(new_mask, cpus_allowed);
- goto again;
- }
+ cpuset_cpus_allowed(p, cpus_allowed);
+ if (!cpumask_subset(new_mask, cpus_allowed)) {
+ /*
+ * We must have raced with a concurrent cpuset update.
+ * Just reset the cpumask to the cpuset's cpus_allowed.
+ */
+ cpumask_copy(new_mask, cpus_allowed);
+ goto again;
}
+
out_free_new_mask:
free_cpumask_var(new_mask);
out_free_cpus_allowed:
free_cpumask_var(cpus_allowed);
+ return retval;
+}
+
+long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+{
+ struct task_struct *p;
+ int retval;
+
+ rcu_read_lock();
+
+ p = find_process_by_pid(pid);
+ if (!p) {
+ rcu_read_unlock();
+ return -ESRCH;
+ }
+
+ /* Prevent p going away */
+ get_task_struct(p);
+ rcu_read_unlock();
+
+ if (p->flags & PF_NO_SETAFFINITY) {
+ retval = -EINVAL;
+ goto out_put_task;
+ }
+
+ if (!check_same_owner(p)) {
+ rcu_read_lock();
+ if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+ rcu_read_unlock();
+ retval = -EPERM;
+ goto out_put_task;
+ }
+ rcu_read_unlock();
+ }
+
+ retval = security_task_setscheduler(p);
+ if (retval)
+ goto out_put_task;
+
+ retval = __sched_setaffinity(p, in_mask);
out_put_task:
put_task_struct(p);
return retval;
next prev parent reply other threads:[~2021-08-23 9:26 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 11:24 [PATCH v11 00/16] Add support for 32-bit tasks on asymmetric AArch32 systems Will Deacon
2021-07-30 11:24 ` [PATCH v11 01/16] sched: Introduce task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2021-08-23 9:26 ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 02/16] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2021-08-23 9:26 ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 03/16] cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() Will Deacon
2021-08-23 9:26 ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 04/16] cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq() Will Deacon
2021-08-23 9:26 ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 05/16] sched: Reject CPU affinity changes based on task_cpu_possible_mask() Will Deacon
2021-08-23 9:26 ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 06/16] sched: Introduce task_struct::user_cpus_ptr to track requested affinity Will Deacon
2021-08-23 9:26 ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 07/16] sched: Split the guts of sched_setaffinity() into a helper function Will Deacon
2021-08-17 15:40 ` Peter Zijlstra
2021-08-18 10:50 ` Will Deacon
2021-08-18 10:56 ` Peter Zijlstra
2021-08-18 11:11 ` Will Deacon
2021-08-23 9:26 ` tip-bot2 for Will Deacon [this message]
2021-07-30 11:24 ` [PATCH v11 08/16] sched: Allow task CPU affinity to be restricted on asymmetric systems Will Deacon
2021-08-17 15:10 ` Peter Zijlstra
2021-08-18 10:42 ` Will Deacon
2021-08-18 10:56 ` Peter Zijlstra
2021-08-18 11:53 ` Peter Zijlstra
2021-08-18 12:19 ` Will Deacon
2021-08-18 11:06 ` Peter Zijlstra
2021-08-17 15:41 ` Peter Zijlstra
2021-08-18 10:43 ` Will Deacon
2021-08-23 9:26 ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 09/16] sched: Introduce dl_task_check_affinity() to check proposed affinity Will Deacon
2021-08-23 9:26 ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 10/16] arm64: Implement task_cpu_possible_mask() Will Deacon
2021-07-30 11:24 ` [PATCH v11 11/16] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon
2021-07-30 11:24 ` [PATCH v11 12/16] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2021-07-30 11:24 ` [PATCH v11 13/16] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2021-07-30 11:24 ` [PATCH v11 14/16] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2021-07-30 11:24 ` [PATCH v11 15/16] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon
2021-07-30 11:24 ` [PATCH v11 16/16] Documentation: arm64: describe asymmetric 32-bit support Will Deacon
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