Applies the counting-based method for monitoring lockless pgtable walks on read_user_stack_slow. Signed-off-by: Leonardo Bras <leonardo@xxxxxxxxxxxxx> --- arch/powerpc/perf/callchain.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c index c84bbd4298a0..9d76194a2a8f 100644 --- a/arch/powerpc/perf/callchain.c +++ b/arch/powerpc/perf/callchain.c @@ -113,16 +113,18 @@ static int read_user_stack_slow(void __user *ptr, void *buf, int nb) int ret = -EFAULT; pgd_t *pgdir; pte_t *ptep, pte; + struct mm_struct *mm = current->mm; unsigned shift; unsigned long addr = (unsigned long) ptr; unsigned long offset; unsigned long pfn, flags; void *kaddr; - pgdir = current->mm->pgd; + pgdir = mm->pgd; if (!pgdir) return -EFAULT; + start_lockless_pgtbl_walk(mm); local_irq_save(flags); ptep = find_current_mm_pte(pgdir, addr, NULL, &shift); if (!ptep) @@ -146,6 +148,7 @@ static int read_user_stack_slow(void __user *ptr, void *buf, int nb) ret = 0; err_out: local_irq_restore(flags); + end_lockless_pgtbl_walk(mm); return ret; } -- 2.20.1
