diff options
Diffstat (limited to 'arch/mips/kernel/mips-mt-fpaff.c')
| -rw-r--r-- | arch/mips/kernel/mips-mt-fpaff.c | 87 |
1 files changed, 61 insertions, 26 deletions
diff --git a/arch/mips/kernel/mips-mt-fpaff.c b/arch/mips/kernel/mips-mt-fpaff.c index f5981c49910..2340f11dc29 100644 --- a/arch/mips/kernel/mips-mt-fpaff.c +++ b/arch/mips/kernel/mips-mt-fpaff.c @@ -3,6 +3,7 @@ * Copyright (C) 2005 Mips Technologies, Inc */ #include <linux/cpu.h> +#include <linux/cpuset.h> #include <linux/cpumask.h> #include <linux/delay.h> #include <linux/kernel.h> @@ -39,6 +40,21 @@ static inline struct task_struct *find_process_by_pid(pid_t pid) return pid ? find_task_by_vpid(pid) : current; } +/* + * check the target process has a UID that matches the current process's + */ +static bool check_same_owner(struct task_struct *p) +{ + const struct cred *cred = current_cred(), *pcred; + bool match; + + rcu_read_lock(); + pcred = __task_cred(p); + match = (cred->euid == pcred->euid || + cred->euid == pcred->uid); + rcu_read_unlock(); + return match; +} /* * mipsmt_sys_sched_setaffinity - set the cpu affinity of a process @@ -46,12 +62,10 @@ static inline struct task_struct *find_process_by_pid(pid_t pid) asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len, unsigned long __user *user_mask_ptr) { - cpumask_t new_mask; - cpumask_t effective_mask; - int retval; - struct task_struct *p; + cpumask_var_t cpus_allowed, new_mask, effective_mask; struct thread_info *ti; - uid_t euid; + struct task_struct *p; + int retval; if (len < sizeof(new_mask)) return -EINVAL; @@ -60,53 +74,74 @@ asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len, return -EFAULT; get_online_cpus(); - read_lock(&tasklist_lock); + rcu_read_lock(); p = find_process_by_pid(pid); if (!p) { - read_unlock(&tasklist_lock); + rcu_read_unlock(); put_online_cpus(); return -ESRCH; } - /* - * It is not safe to call set_cpus_allowed with the - * tasklist_lock held. We will bump the task_struct's - * usage count and drop tasklist_lock before invoking - * set_cpus_allowed. - */ + /* Prevent p going away */ get_task_struct(p); + rcu_read_unlock(); - euid = current_euid(); + 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; + } + if (!alloc_cpumask_var(&effective_mask, GFP_KERNEL)) { + retval = -ENOMEM; + goto out_free_new_mask; + } retval = -EPERM; - if (euid != p->cred->euid && euid != p->cred->uid && - !capable(CAP_SYS_NICE)) { - read_unlock(&tasklist_lock); + if (!check_same_owner(p) && !capable(CAP_SYS_NICE)) goto out_unlock; - } retval = security_task_setscheduler(p, 0, NULL); if (retval) goto out_unlock; /* Record new user-specified CPU set for future reference */ - p->thread.user_cpus_allowed = new_mask; - - /* Unlock the task list */ - read_unlock(&tasklist_lock); + cpumask_copy(&p->thread.user_cpus_allowed, new_mask); + again: /* Compute new global allowed CPU set if necessary */ ti = task_thread_info(p); if (test_ti_thread_flag(ti, TIF_FPUBOUND) && - cpus_intersects(new_mask, mt_fpu_cpumask)) { - cpus_and(effective_mask, new_mask, mt_fpu_cpumask); - retval = set_cpus_allowed_ptr(p, &effective_mask); + cpus_intersects(*new_mask, mt_fpu_cpumask)) { + cpus_and(*effective_mask, *new_mask, mt_fpu_cpumask); + retval = set_cpus_allowed_ptr(p, effective_mask); } else { + cpumask_copy(effective_mask, new_mask); clear_ti_thread_flag(ti, TIF_FPUBOUND); - retval = set_cpus_allowed_ptr(p, &new_mask); + retval = set_cpus_allowed_ptr(p, new_mask); } + if (!retval) { + cpuset_cpus_allowed(p, cpus_allowed); + if (!cpumask_subset(effective_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; + } + } out_unlock: + free_cpumask_var(effective_mask); +out_free_new_mask: + free_cpumask_var(new_mask); +out_free_cpus_allowed: + free_cpumask_var(cpus_allowed); +out_put_task: put_task_struct(p); put_online_cpus(); return retval; |