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Subject[PATCH 4.15 004/146] bpf: cpumap: use GFP_KERNEL instead of GFP_ATOMIC in __cpu_map_entry_alloc()
Date
4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jason Wang <jasowang@redhat.com>

commit 7fc17e909edfb9bf421ee04e981d3d474175c7c7 upstream.

There're several implications after commit 0bf7800f1799 ("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: 0bf7800f1799 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/bpf/cpumap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -339,7 +339,7 @@ static int cpu_map_kthread_run(void *dat

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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