Commit 7fc17e90 authored Feb 14, 2018 by Jason Wang Committed by Daniel Borkmann Feb 14, 2018

bpf: cpumap: use GFP_KERNEL instead of GFP_ATOMIC in __cpu_map_entry_alloc()



There're several implications after commit 0bf7800f ("ptr_ring:
try vmalloc() when kmalloc() fails") with the using of vmalloc() since
can't allow GFP_ATOMIC but mandate GFP_KERNEL. This will lead a WARN
since cpumap try to call with GFP_ATOMIC. Fortunately, entry
allocation of cpumap can only be done through syscall path which means
GFP_ATOMIC is not necessary, so fixing this by replacing GFP_ATOMIC
with GFP_KERNEL.

Reported-by:  <syzbot+1a240cdb1f4cc88819df@syzkaller.appspotmail.com>
Fixes: 0bf7800f ("ptr_ring: try vmalloc() when kmalloc() fails")
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: akpm@linux-foundation.org
Cc: dhowells@redhat.com
Cc: hannes@cmpxchg.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 952fad8e

kernel/bpf/cpumap.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -334,7 +334,7 @@ static int cpu_map_kthread_run(void *data)
		static struct bpf_cpu_map_entry *__cpu_map_entry_alloc(u32 qsize, u32 cpu,
		int map_id)
		{
		gfp_t gfp = GFP_ATOMIC\|__GFP_NOWARN;
		gfp_t gfp = GFP_KERNEL \| __GFP_NOWARN;
		struct bpf_cpu_map_entry *rcpu;
		int numa, err;

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