Eric Lee / smarc-ti-linux-kernel

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Commit 86fc80f16e8a2449d5827bf1a9838b7fd9f70097

Authored by Thomas Gleixner
Committed by James Morris
1 parent 67fa4880c5
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

capabilities: Use RCU to protect task lookup in sys_capget 

cap_get_target_pid() protects the task lookup with tasklist_lock.
security_capget() is called under tasklist_lock as well but
tasklist_lock does not protect anything there. The capabilities are
protected by RCU already.

So tasklist_lock only protects the lookup and prevents the task going
away, which can be done with rcu_read_lock() as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: James Morris <jmorris@namei.org>

Showing 1 changed file with 2 additions and 2 deletions Side-by-side Diff

... ... @@ -135,7 +135,7 @@
135 135 if (pid && (pid != task_pid_vnr(current))) {
136 136 struct task_struct *target;
137 137  
138   - read_lock(&tasklist_lock);
  138 + rcu_read_lock();
139 139  
140 140 target = find_task_by_vpid(pid);
141 141 if (!target)
... ... @@ -143,7 +143,7 @@
143 143 else
144 144 ret = security_capget(target, pEp, pIp, pPp);
145 145  
146   - read_unlock(&tasklist_lock);
  146 + rcu_read_unlock();
147 147 } else
148 148 ret = security_capget(current, pEp, pIp, pPp);
149 149