Calling a kmalloc_node on a possible node which is not yet onlined can lead to panic. Currently node_present_pages() doesn't verify the node is online before accessing the pgdat for the node. However pgdat struct may not be available resulting in a crash.
NIP [c0000000003d55f4] ___slab_alloc+0x1f4/0x760 LR [c0000000003d5b94] __slab_alloc+0x34/0x60 Call Trace: [c0000008b3783960] [c0000000003d5734] ___slab_alloc+0x334/0x760 (unreliable) [c0000008b3783a40] [c0000000003d5b94] __slab_alloc+0x34/0x60 [c0000008b3783a70] [c0000000003d6fa0] __kmalloc_node+0x110/0x490 [c0000008b3783af0] [c0000000003443d8] kvmalloc_node+0x58/0x110 [c0000008b3783b30] [c0000000003fee38] mem_cgroup_css_online+0x108/0x270 [c0000008b3783b90] [c000000000235aa8] online_css+0x48/0xd0 [c0000008b3783bc0] [c00000000023eaec] cgroup_apply_control_enable+0x2ec/0x4d0 [c0000008b3783ca0] [c000000000242318] cgroup_mkdir+0x228/0x5f0 [c0000008b3783d10] [c00000000051e170] kernfs_iop_mkdir+0x90/0xf0 [c0000008b3783d50] [c00000000043dc00] vfs_mkdir+0x110/0x230 [c0000008b3783da0] [c000000000441c90] do_mkdirat+0xb0/0x1a0 [c0000008b3783e20] [c00000000000b278] system_call+0x5c/0x68 Fix this by verifying the node is online before accessing the pgdat structure. Fix the same for node_spanned_pages() too. Cc: Andrew Morton <[email protected]> Cc: [email protected] Cc: Mel Gorman <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Sachin Sant <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Christopher Lameter <[email protected]> Cc: [email protected] Cc: Joonsoo Kim <[email protected]> Cc: Kirill Tkhai <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Srikar Dronamraju <[email protected]> Cc: Bharata B Rao <[email protected]> Cc: Nathan Lynch <[email protected]> Reported-by: Sachin Sant <[email protected]> Tested-by: Sachin Sant <[email protected]> Signed-off-by: Srikar Dronamraju <[email protected]> --- include/linux/mmzone.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index f3f264826423..88078a3b95e5 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -756,8 +756,10 @@ typedef struct pglist_data { atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS]; } pg_data_t; -#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) -#define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages) +#define node_present_pages(nid) \ + (node_online(nid) ? NODE_DATA(nid)->node_present_pages : 0) +#define node_spanned_pages(nid) \ + (node_online(nid) ? NODE_DATA(nid)->node_spanned_pages : 0) #ifdef CONFIG_FLAT_NODE_MEM_MAP #define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr)) #else -- 2.18.1
