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Commit 5a6cec3a authored by Ingo Molnar's avatar Ingo Molnar
Browse files

perf_counter, x86: Fix call-chain walking 



Fix the ptregs variant when we hit user-mode tasks.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 3efa1cc9

arch/x86/kernel/cpu/perf_counter.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -1644,7 +1644,9 @@ perf_callchain_user(struct pt_regs *regs, struct perf_callchain_entry *entry) 
	const void __user *fp;

	const void __user *fp;

	int nr = entry->nr;

	int nr = entry->nr;





	regs = (struct pt_regs *)current->thread.sp0 - 1;

	if (!user_mode(regs))

		regs = task_pt_regs(current);



	fp   = (void __user *)regs->bp;

	fp   = (void __user *)regs->bp;





	callchain_store(entry, regs->ip);

	callchain_store(entry, regs->ip);
@@ -1656,7 +1658,7 @@ perf_callchain_user(struct pt_regs *regs, struct perf_callchain_entry *entry) 
		if (!copy_stack_frame(fp, &frame))

		if (!copy_stack_frame(fp, &frame))

			break;

			break;





		if ((unsigned long)fp < user_stack_pointer(regs))

		if ((unsigned long)fp < regs->sp)

			break;

			break;





		callchain_store(entry, frame.return_address);

		callchain_store(entry, frame.return_address);