powerpc: Do not assign thread.tidr if already assigned

vaibhav92 · mpe · commit 7e4d4233260b · 2017-11-29T19:56:18.000+11:00
If set_thread_tidr() is called twice for same task_struct then it will allocate a new tidr value to it leaving the previous value still dangling in the vas_thread_ida table. To fix this the patch changes set_thread_tidr() to check if a tidr value is already assigned to the task_struct and if yes then returns zero. Fixes: ec233ed("powerpc: Add support for setting SPRN_TIDR") Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> [mpe: Modify to return 0 in the success case, not the TID value] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
@@ -1577,6 +1577,9 @@ int set_thread_tidr(struct task_struct *t)
 	if (t != current)
 		return -EINVAL;
 
+	if (t->thread.tidr)
+		return 0;
+
 	rc = assign_thread_tidr();
 	if (rc < 0)
 		return rc;
