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SubjectRe: [PATCH v2 3/3] mm/vmalloc: move VM_UNINITIALIZED just before show_numa_info
On 09/03/2013 11:00 AM, Wanpeng Li wrote:
> The VM_UNINITIALIZED/VM_UNLIST flag introduced by commit f5252e00(mm: avoid
> null pointer access in vm_struct via /proc/vmallocinfo) is used to avoid
> accessing the pages field with unallocated page when show_numa_info() is
> called. This patch move the check just before show_numa_info in order that
> some messages still can be dumped via /proc/vmallocinfo.
>
> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>

Hmmm, sorry again. Please revert commit
d157a55815ffff48caec311dfb543ce8a79e283e. That said, we could still
do the check in show_numa_info like before.

> ---
> mm/vmalloc.c | 10 +++++-----
> 1 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index e3ec8b4..c4720cd 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2590,11 +2590,6 @@ static int s_show(struct seq_file *m, void *p)
>
> v = va->vm;
>
> - /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
> - smp_rmb();
> - if (v->flags & VM_UNINITIALIZED)
> - return 0;
> -
> seq_printf(m, "0x%pK-0x%pK %7ld",
> v->addr, v->addr + v->size, v->size);
>
> @@ -2622,6 +2617,11 @@ static int s_show(struct seq_file *m, void *p)
> if (v->flags & VM_VPAGES)
> seq_printf(m, " vpages");
>
> + /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */
> + smp_rmb();
> + if (v->flags & VM_UNINITIALIZED)
> + return 0;
> +
> show_numa_info(m, v);
> seq_putc(m, '\n');
> return 0;
>


--
Thanks.
Zhang Yanfei


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