On 06.04.20 05:55, qiwuchen55@xxxxxxxxx wrote:
> From: chenqiwu <chenqiwu@xxxxxxxxxx>
>
> This patch use VM_BUG_ON*() helpers instead of simple BUG_ON()
> in some of the main mm codes. If CONFIG_DEBUG_VM is set, we can
> get more debugging information when the bug is hit.
>
The "issue" in this context of VM_BUG_ON*() is that, without
CONFIG_DEBUG_VM, there won't really be any runtime checks anymore,
meaning a production system would not stop and BUG_ON() (which would be
disruptive, but there is a chance to debug this), instead it would
happily continue to run, eventually messing up something else.
This is a clear change introduced in this series.
My gut feeling is that we want to convert this on a per-case basis instead.
> Signed-off-by: chenqiwu <chenqiwu@xxxxxxxxxx>
> ---
> mm/memory.c | 25 +++++++++++++------------
> mm/mmap.c | 8 ++++----
> mm/rmap.c | 10 +++++-----
> mm/swapfile.c | 16 ++++++++--------
> mm/vmscan.c | 6 +++---
> 5 files changed, 33 insertions(+), 32 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 586271f..082472f 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -912,7 +912,7 @@ static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src
> if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) {
> int err;
>
> - VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, vma);
> + VM_BUG_ON_VMA(next - addr != HPAGE_PUD_SIZE, vma);
unrelated change.
--
Thanks,
David / dhildenb
