hugepd_free() used __get_cpu_var() once. Nothing ensured that the code accessing the variable did not migrate from one CPU to another and soon this was noticed by Tiejun Chen in 94b09d755462 ("powerpc/hugetlb: Replace __get_cpu_var with get_cpu_var"). So we had it fixed.
Christoph Lameter was doing his __get_cpu_var() replaces and forgot PowerPC. Then he noticed this and sent his fixed up batch again which got applied as 69111bac42f5 ("powerpc: Replace __get_cpu_var uses"). The careful reader will noticed one little detail: get_cpu_var() got replaced with this_cpu_ptr(). So now we have a put_cpu_var() which does a preempt_enable() and nothing that does preempt_disable() so we underflow the preempt counter. Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> Cc: Christoph Lameter <c...@linux.com> Cc: Michael Ellerman <m...@ellerman.id.au> Cc: Tiejun Chen <tiejun.c...@windriver.com> Cc: <sta...@vger.kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de> --- arch/powerpc/mm/hugetlbpage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 744e24bcb85c..9e8919b39640 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -414,7 +414,7 @@ static void hugepd_free(struct mmu_gather *tlb, void *hugepte) { struct hugepd_freelist **batchp; - batchp = this_cpu_ptr(&hugepd_freelist_cur); + batchp = get_cpu_ptr(&hugepd_freelist_cur); if (atomic_read(&tlb->mm->mm_users) < 2 || cpumask_equal(mm_cpumask(tlb->mm), -- 2.7.0 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev