>From 1454d5ca6209926a52c2fdea9ba41a41a33e4046 Mon Sep 17 00:00:00 2001 From: Heiko Carstens <[email protected]> Date: Tue, 8 Oct 2013 09:46:00 +0200 Subject: [PATCH] powerpc: fix __get_user_pages_fast() irq handling
__get_user_pages_fast() may be called with interrupts disabled (see e.g. get_futex_key() in kernel/futex.c) and therefore should use local_irq_save() and local_irq_restore() instead of local_irq_disable()/enable(). Signed-off-by: Heiko Carstens <[email protected]> --- Please note that this patch is completely untested; not even compile tested. I just realized that there seems to be a bug when looking at the powerpc code ;) arch/powerpc/mm/gup.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c index 6936547..c5f734e 100644 --- a/arch/powerpc/mm/gup.c +++ b/arch/powerpc/mm/gup.c @@ -123,6 +123,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, struct mm_struct *mm = current->mm; unsigned long addr, len, end; unsigned long next; + unsigned long flags; pgd_t *pgdp; int nr = 0; @@ -156,7 +157,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, * So long as we atomically load page table pointers versus teardown, * we can follow the address down to the the page and take a ref on it. */ - local_irq_disable(); + local_irq_save(flags); pgdp = pgd_offset(mm, addr); do { @@ -179,7 +180,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, break; } while (pgdp++, addr = next, addr != end); - local_irq_enable(); + local_irq_restore(flags); return nr; } -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
