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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>,
	Quentin Perret <qperret@google.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: sched/core] sched: Reject CPU affinity changes based on task_cpu_possible_mask()
Date: Mon, 23 Aug 2021 09:26:22 -0000	[thread overview]
Message-ID: <162971078270.25758.8552853367056272946.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210730112443.23245-6-will@kernel.org>

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     234a503e670be01f72841be9fcf68dfb89a1fa8b
Gitweb:        https://git.kernel.org/tip/234a503e670be01f72841be9fcf68dfb89a1fa8b
Author:        Will Deacon <will@kernel.org>
AuthorDate:    Fri, 30 Jul 2021 12:24:32 +01:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 20 Aug 2021 12:32:59 +02:00

sched: Reject CPU affinity changes based on task_cpu_possible_mask()

Reject explicit requests to change the affinity mask of a task via
set_cpus_allowed_ptr() if the requested mask is not a subset of the
mask returned by task_cpu_possible_mask(). This ensures that the
'cpus_mask' for a given task cannot contain CPUs which are incapable of
executing it, except in cases where the affinity is forced.

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>
Reviewed-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20210730112443.23245-6-will@kernel.org
---
 kernel/sched/core.c |  9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b9d4bae..8cec0d2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2709,7 +2709,9 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
 				  const struct cpumask *new_mask,
 				  u32 flags)
 {
+	const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p);
 	const struct cpumask *cpu_valid_mask = cpu_active_mask;
+	bool kthread = p->flags & PF_KTHREAD;
 	unsigned int dest_cpu;
 	struct rq_flags rf;
 	struct rq *rq;
@@ -2718,7 +2720,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
 	rq = task_rq_lock(p, &rf);
 	update_rq_clock(rq);
 
-	if (p->flags & PF_KTHREAD || is_migration_disabled(p)) {
+	if (kthread || is_migration_disabled(p)) {
 		/*
 		 * Kernel threads are allowed on online && !active CPUs,
 		 * however, during cpu-hot-unplug, even these might get pushed
@@ -2732,6 +2734,11 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
 		cpu_valid_mask = cpu_online_mask;
 	}
 
+	if (!kthread && !cpumask_subset(new_mask, cpu_allowed_mask)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	/*
 	 * Must re-check here, to close a race against __kthread_bind(),
 	 * sched_setaffinity() is not guaranteed to observe the flag.

  reply	other threads:[~2021-08-23  9:26 UTC|newest]

Thread overview: 67+ 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 ` Will Deacon
2021-07-30 11:24 ` [PATCH v11 01/16] sched: Introduce task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2021-07-30 11:24   ` 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
2021-07-30 11:24   ` 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
2021-07-30 11:24   ` 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
2021-07-30 11:24   ` 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
2021-07-30 11:24   ` Will Deacon
2021-08-23  9:26   ` tip-bot2 for Will Deacon [this message]
2021-07-30 11:24 ` [PATCH v11 06/16] sched: Introduce task_struct::user_cpus_ptr to track requested affinity Will Deacon
2021-07-30 11:24   ` 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
2021-07-30 11:24   ` Will Deacon
2021-08-17 15:40   ` Peter Zijlstra
2021-08-17 15:40     ` Peter Zijlstra
2021-08-18 10:50     ` Will Deacon
2021-08-18 10:50       ` Will Deacon
2021-08-18 10:56       ` Peter Zijlstra
2021-08-18 10:56         ` Peter Zijlstra
2021-08-18 11:11         ` Will Deacon
2021-08-18 11:11           ` Will Deacon
2021-08-23  9:26   ` [tip: sched/core] " tip-bot2 for Will Deacon
2021-07-30 11:24 ` [PATCH v11 08/16] sched: Allow task CPU affinity to be restricted on asymmetric systems Will Deacon
2021-07-30 11:24   ` Will Deacon
2021-08-17 15:10   ` Peter Zijlstra
2021-08-17 15:10     ` Peter Zijlstra
2021-08-18 10:42     ` Will Deacon
2021-08-18 10:42       ` Will Deacon
2021-08-18 10:56       ` Peter Zijlstra
2021-08-18 10:56         ` Peter Zijlstra
2021-08-18 11:53         ` Peter Zijlstra
2021-08-18 11:53           ` Peter Zijlstra
2021-08-18 12:19           ` Will Deacon
2021-08-18 12:19             ` Will Deacon
2021-08-18 11:06       ` Peter Zijlstra
2021-08-18 11:06         ` Peter Zijlstra
2021-08-17 15:41   ` Peter Zijlstra
2021-08-17 15:41     ` Peter Zijlstra
2021-08-18 10:43     ` Will Deacon
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
2021-07-30 11:24   ` 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   ` 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   ` 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   ` 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   ` 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   ` 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   ` Will Deacon
2021-07-30 11:24 ` [PATCH v11 16/16] Documentation: arm64: describe asymmetric 32-bit support Will Deacon
2021-07-30 11:24   ` Will Deacon

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