Commit f409adf5 authored by Thomas Gleixner's avatar Thomas Gleixner

futex: Protect pid lookup in compat code with RCU

find_task_by_vpid() in compat_sys_get_robust_list() does not require
tasklist_lock. It can be protected with rcu_read_lock as done in
sys_get_robust_list() already.
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Darren Hart <dvhltc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
parent 2b876f95
...@@ -146,7 +146,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr, ...@@ -146,7 +146,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
struct task_struct *p; struct task_struct *p;
ret = -ESRCH; ret = -ESRCH;
read_lock(&tasklist_lock); rcu_read_lock();
p = find_task_by_vpid(pid); p = find_task_by_vpid(pid);
if (!p) if (!p)
goto err_unlock; goto err_unlock;
...@@ -157,7 +157,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr, ...@@ -157,7 +157,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
!capable(CAP_SYS_PTRACE)) !capable(CAP_SYS_PTRACE))
goto err_unlock; goto err_unlock;
head = p->compat_robust_list; head = p->compat_robust_list;
read_unlock(&tasklist_lock); rcu_read_unlock();
} }
if (put_user(sizeof(*head), len_ptr)) if (put_user(sizeof(*head), len_ptr))
...@@ -165,7 +165,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr, ...@@ -165,7 +165,7 @@ compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
return put_user(ptr_to_compat(head), head_ptr); return put_user(ptr_to_compat(head), head_ptr);
err_unlock: err_unlock:
read_unlock(&tasklist_lock); rcu_read_unlock();
return ret; return ret;
} }
......
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