| Message ID | 20210927020922.87449-1-wangkefeng.wang@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | slub: Add back check for free nonslab objects | expand |
sorry，wrong patch, please ignore On 2021/9/27 10:09, Kefeng Wang wrote: > After commit ("f227f0faf63b slub: fix unreclaimable slab stat for bulk > free"), the check for free nonslab page is replaced by VM_BUG_ON_PAGE, > which only check with CONFIG_DEBUG_VM enabled, but this config may > impact performance, so it only for debug. > > Commit ("0937502af7c9 slub: Add check for kfree() of non slab objects.") > add the ability, which should be needed in any configs to catch the > invalid free, they even could be potential issue, eg, memory corruption, > use after free and double free, so replace VM_BUG_ON_PAGE to WARN_ON, and > add dump_page() to help use to debug the issue. > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > --- > mm/slub.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 3095b889fab4..1bfe09098485 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -3522,7 +3522,8 @@ static inline void free_nonslab_page(struct page *page, void *object) > { > unsigned int order = compound_order(page); > > - VM_BUG_ON_PAGE(!PageCompound(page), page); > + if (WARN_ON(!PageCompound(page))) > + dump_page(page); > kfree_hook(object); > mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << order)); > __free_pages(page, order);
diff --git a/mm/slub.c b/mm/slub.c index 3095b889fab4..1bfe09098485 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3522,7 +3522,8 @@ static inline void free_nonslab_page(struct page *page, void *object) { unsigned int order = compound_order(page); - VM_BUG_ON_PAGE(!PageCompound(page), page); + if (WARN_ON(!PageCompound(page))) + dump_page(page); kfree_hook(object); mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << order)); __free_pages(page, order);
After commit ("f227f0faf63b slub: fix unreclaimable slab stat for bulk free"), the check for free nonslab page is replaced by VM_BUG_ON_PAGE, which only check with CONFIG_DEBUG_VM enabled, but this config may impact performance, so it only for debug. Commit ("0937502af7c9 slub: Add check for kfree() of non slab objects.") add the ability, which should be needed in any configs to catch the invalid free, they even could be potential issue, eg, memory corruption, use after free and double free, so replace VM_BUG_ON_PAGE to WARN_ON, and add dump_page() to help use to debug the issue. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- mm/slub.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)