powerpc: Fix MAX_STACK_TRACE_ENTRIES too low warning again
Saw this warning again, and this time from the ret_from_fork path.
It seems we could clear the back chain earlier in copy_thread(), which
could cover both path, and also fix potential lockdep usage in
schedule_tail(), or exception occurred before we clear the back chain.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index ceb4e7b..21981a8 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -971,6 +971,7 @@
* do some house keeping and then return from the fork or clone
* system call, using the stack frame created above.
*/
+ ((unsigned long *)sp)[0] = 0;
sp -= sizeof(struct pt_regs);
kregs = (struct pt_regs *) sp;
sp -= STACK_FRAME_OVERHEAD;