From mboxrd@z Thu Jan 1 00:00:00 1970 From: jeremy.linton@arm.com (Jeremy Linton) Date: Wed, 1 Aug 2018 15:04:17 -0500 Subject: [RFC 1/2] slub: Avoid trying to allocate memory on offline nodes In-Reply-To: <20180801200418.1325826-1-jeremy.linton@arm.com> References: <20180801200418.1325826-1-jeremy.linton@arm.com> Message-ID: <20180801200418.1325826-2-jeremy.linton@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org If a user calls the *alloc_node() functions with an invalid node its possible to crash in alloc_pages_nodemask because NODE_DATA() returns a bad node, which propogates into the node zonelist in prepare_alloc_pages. This avoids that by not trying to allocate new slabs against offline nodes. (example backtrace) __alloc_pages_nodemask+0x128/0xf48 allocate_slab+0x94/0x528 new_slab+0x68/0xc8 ___slab_alloc+0x44c/0x520 __slab_alloc+0x50/0x68 kmem_cache_alloc_node_trace+0xe0/0x230 Signed-off-by: Jeremy Linton --- mm/slub.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index 51258eff4178..e03719bac1e2 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2519,6 +2519,8 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, if (unlikely(!node_match(page, searchnode))) { stat(s, ALLOC_NODE_MISMATCH); deactivate_slab(s, page, c->freelist, c); + if (!node_online(searchnode)) + node = NUMA_NO_NODE; goto new_slab; } } -- 2.14.3