[RFC 1/2] mm, slub: prevent kmalloc_node crashes and memory leaks
Bharata B Rao
bharata at linux.ibm.com
Fri Mar 20 19:44:47 AEDT 2020
On Fri, Mar 20, 2020 at 09:37:18AM +0100, Vlastimil Babka wrote:
> On 3/20/20 4:42 AM, Bharata B Rao wrote:
> > On Thu, Mar 19, 2020 at 02:47:58PM +0100, Vlastimil Babka wrote:
> >> diff --git a/mm/slub.c b/mm/slub.c
> >> index 17dc00e33115..7113b1f9cd77 100644
> >> --- a/mm/slub.c
> >> +++ b/mm/slub.c
> >> @@ -1973,8 +1973,6 @@ static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
> >>
> >> if (node == NUMA_NO_NODE)
> >> searchnode = numa_mem_id();
> >> - else if (!node_present_pages(node))
> >> - searchnode = node_to_mem_node(node);
> >>
> >> object = get_partial_node(s, get_node(s, searchnode), c, flags);
> >> if (object || node != NUMA_NO_NODE)
> >> @@ -2563,17 +2561,27 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
> >> struct page *page;
> >>
> >> page = c->page;
> >> - if (!page)
> >> + if (!page) {
> >> + /*
> >> + * if the node is not online or has no normal memory, just
> >> + * ignore the node constraint
> >> + */
> >> + if (unlikely(node != NUMA_NO_NODE &&
> >> + !node_state(node, N_NORMAL_MEMORY)))
> >> + node = NUMA_NO_NODE;
> >> goto new_slab;
> >> + }
> >> redo:
> >>
> >> if (unlikely(!node_match(page, node))) {
> >> - int searchnode = node;
> >> -
> >> - if (node != NUMA_NO_NODE && !node_present_pages(node))
> >> - searchnode = node_to_mem_node(node);
> >> -
> >> - if (unlikely(!node_match(page, searchnode))) {
> >> + /*
> >> + * same as above but node_match() being false already
> >> + * implies node != NUMA_NO_NODE
> >> + */
> >> + if (!node_state(node, N_NORMAL_MEMORY)) {
> >> + node = NUMA_NO_NODE;
> >> + goto redo;
> >> + } else {
> >> stat(s, ALLOC_NODE_MISMATCH);
> >> deactivate_slab(s, page, c->freelist, c);
> >> goto new_slab;
> >
> > This fixes the problem I reported at
> > https://lore.kernel.org/linux-mm/20200317092624.GB22538@in.ibm.com/
>
> Thanks, I hope it means I can make it Reported-and-tested-by: you
It was reeported first by PUVICHAKRAVARTHY RAMACHANDRAN <puvichakravarthy at in.ibm.com>
You can add my tested-by.
Regards,
Bharata.
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