mm: fix BUG splat with kvmalloc + GFP_ATOMIC

Martin Zaharinov reports BUG with 5.19.10 kernel:
 kernel BUG at mm/vmalloc.c:2437!
 invalid opcode: 0000 [#1] SMP
 CPU: 28 PID: 0 Comm: swapper/28 Tainted: G        W  O      5.19.9 #1
 [..]
 RIP: 0010:__get_vm_area_node+0x120/0x130
  __vmalloc_node_range+0x96/0x1e0
  kvmalloc_node+0x92/0xb0
  bucket_table_alloc.isra.0+0x47/0x140
  rhashtable_try_insert+0x3a4/0x440
  rhashtable_insert_slow+0x1b/0x30
 [..]

bucket_table_alloc uses kvzalloc(GPF_ATOMIC).  If kmalloc fails, this now
falls through to vmalloc and hits code paths that assume GFP_KERNEL.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: a421ef3 ("mm: allow !GFP_KERNEL allocations for kvmalloc")
Signed-off-by: Florian Westphal <[email protected]>
Suggested-by: Michal Hocko <[email protected]>
Link: https://lore.kernel.org/linux-mm/Yy3MS2uhSgjF47dy@pc636/T/#t
Acked-by: Michal Hocko <[email protected]>
Reported-by: Martin Zaharinov <[email protected]>
Cc: Uladzislau Rezki (Sony) <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Florian Westphal

mm/util.c

@@ -619,6 +619,10 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node)
 	if (ret || size <= PAGE_SIZE)
 		return ret;
 
+	/* non-sleeping allocations are not supported by vmalloc */
+	if (!gfpflags_allow_blocking(flags))
+		return NULL;
+
 	/* Don't even allow crazy sizes */
 	if (unlikely(size > INT_MAX)) {
 		WARN_ON_ONCE(!(flags & __GFP_NOWARN));