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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