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Commit af945cf4 authored by Li Zhong's avatar Li Zhong Committed by Benjamin Herrenschmidt
Browse files

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: default avatarLi Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent b80ec3dc

arch/powerpc/kernel/entry_32.S

+0 −2
Original line number Diff line number Diff line
@@ -439,8 +439,6 @@ ret_from_fork: 
ret_from_kernel_thread:

	REST_NVGPRS(r1)

	bl	schedule_tail

	li	r3,0

	stw	r3,0(r1)

	mtlr	r14

	mr	r3,r15

	PPC440EP_ERR42

arch/powerpc/kernel/entry_64.S

+0 −2
Original line number Diff line number Diff line
@@ -376,8 +376,6 @@ _GLOBAL(ret_from_fork) 
_GLOBAL(ret_from_kernel_thread)

	bl	.schedule_tail

	REST_NVGPRS(r1)

	li	r3,0

	std	r3,0(r1)

	ld	r14, 0(r14)

	mtlr	r14

	mr	r3,r15

arch/powerpc/kernel/process.c

+1 −0
Original line number Diff line number Diff line
@@ -971,6 +971,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp, 
	 * 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;