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From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Quentin Perret <qperret@google.com>, Tejun Heo <tj@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	kernel-team@android.com,
	Valentin Schneider <Valentin.Schneider@arm.com>
Subject: [PATCH v9 11/20] sched: Split the guts of sched_setaffinity() into a helper function
Date: Tue,  8 Jun 2021 19:03:04 +0100	[thread overview]
Message-ID: <20210608180313.11502-12-will@kernel.org> (raw)
In-Reply-To: <20210608180313.11502-1-will@kernel.org>

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.

Reviewed-by: Valentin Schneider <Valentin.Schneider@arm.com>
Signed-off-by: Will Deacon <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 f6ea3d7a07f2..d151446d5987 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6787,53 +6787,22 @@ 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)
 {
-	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,
@@ -6854,23 +6823,63 @@ 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;
-- 
2.32.0.rc1.229.g3e70b5a671-goog


WARNING: multiple messages have this Message-ID
From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Quentin Perret <qperret@google.com>, Tejun Heo <tj@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	kernel-team@android.com,
	Valentin Schneider <Valentin.Schneider@arm.com>
Subject: [PATCH v9 11/20] sched: Split the guts of sched_setaffinity() into a helper function
Date: Tue,  8 Jun 2021 19:03:04 +0100	[thread overview]
Message-ID: <20210608180313.11502-12-will@kernel.org> (raw)
In-Reply-To: <20210608180313.11502-1-will@kernel.org>

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.

Reviewed-by: Valentin Schneider <Valentin.Schneider@arm.com>
Signed-off-by: Will Deacon <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 f6ea3d7a07f2..d151446d5987 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6787,53 +6787,22 @@ 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)
 {
-	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,
@@ -6854,23 +6823,63 @@ 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;
-- 
2.32.0.rc1.229.g3e70b5a671-goog


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2021-06-08 18:04 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08 18:02 [PATCH v9 00/20] Add support for 32-bit tasks on asymmetric AArch32 systems Will Deacon
2021-06-08 18:02 ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 01/20] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 02/20] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 03/20] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 04/20] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 05/20] sched: Introduce task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-08 18:02 ` [PATCH v9 06/20] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2021-06-08 18:02   ` Will Deacon
2021-06-10 12:59   ` Valentin Schneider
2021-06-10 12:59     ` Valentin Schneider
2021-06-08 18:03 ` [PATCH v9 07/20] cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 08/20] cpuset: Cleanup cpuset_cpus_allowed_fallback() use in select_fallback_rq() Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-10 12:59   ` Valentin Schneider
2021-06-10 12:59     ` Valentin Schneider
2021-06-08 18:03 ` [PATCH v9 09/20] sched: Reject CPU affinity changes based on task_cpu_possible_mask() Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 10/20] sched: Introduce task_struct::user_cpus_ptr to track requested affinity Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` Will Deacon [this message]
2021-06-08 18:03   ` [PATCH v9 11/20] sched: Split the guts of sched_setaffinity() into a helper function Will Deacon
2021-06-08 18:03 ` [PATCH v9 12/20] sched: Allow task CPU affinity to be restricted on asymmetric systems Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-10 13:00   ` Valentin Schneider
2021-06-10 13:00     ` Valentin Schneider
2021-06-08 18:03 ` [PATCH v9 13/20] sched: Introduce dl_task_check_affinity() to check proposed affinity Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 14/20] arm64: Implement task_cpu_possible_mask() Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 15/20] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 16/20] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 17/20] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 18/20] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 19/20] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-08 18:03 ` [PATCH v9 20/20] Documentation: arm64: describe asymmetric 32-bit support Will Deacon
2021-06-08 18:03   ` Will Deacon
2021-06-11 16:15 ` [PATCH v9 00/20] Add support for 32-bit tasks on asymmetric AArch32 systems Will Deacon
2021-06-11 16:15   ` Will Deacon

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