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authorOng Boon Leong <boon.leong.ong@intel.com>2021-03-31 21:25:03 +0800
committerDavid S. Miller <davem@davemloft.net>2021-03-31 15:15:23 -0700
commit622d13694b5f048c01caa7ba548498d9880d4cb0 (patch)
tree1c33751ca3d24ab7507578ddf0ef1713110dc85b /net/core
parentc609e6aae4efcf383fe86b195d1b060befcb3666 (diff)
xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model
xdp_return_frame() may be called outside of NAPI context to return xdpf back to page_pool. xdp_return_frame() calls __xdp_return() with napi_direct = false. For page_pool memory model, __xdp_return() calls xdp_return_frame_no_direct() unconditionally and below false negative kernel BUG throw happened under preempt-rt build: [ 430.450355] BUG: using smp_processor_id() in preemptible [00000000] code: modprobe/3884 [ 430.451678] caller is __xdp_return+0x1ff/0x2e0 [ 430.452111] CPU: 0 PID: 3884 Comm: modprobe Tainted: G U E 5.12.0-rc2+ #45 Changes in v2: - This patch fixes the issue by making xdp_return_frame_no_direct() is only called if napi_direct = true, as recommended for better by Jesper Dangaard Brouer. Thanks! Fixes: 2539650fadbf ("xdp: Helpers for disabling napi_direct of xdp_return_frame") Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/xdp.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 05354976c1fc..858276e72c68 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -350,7 +350,8 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
/* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
page = virt_to_head_page(data);
- napi_direct &= !xdp_return_frame_no_direct();
+ if (napi_direct && xdp_return_frame_no_direct())
+ napi_direct = false;
page_pool_put_full_page(xa->page_pool, page, napi_direct);
rcu_read_unlock();
break;