From: Ong Boon Leong <boon.leong.ong@intel.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org,
Ong Boon Leong <boon.leong.ong@intel.com>
Subject: [PATCH net 1/1] xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model
Date: Mon, 29 Mar 2021 16:00:39 +0800 [thread overview]
Message-ID: <20210329080039.32753-1-boon.leong.ong@intel.com> (raw)
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
So, this patch fixes the issue by adding "if (napi_direct)" condition
to skip calling xdp_return_frame_no_direct() if napi_direct = false.
Fixes: 2539650fadbf ("xdp: Helpers for disabling napi_direct of xdp_return_frame")
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
---
net/core/xdp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 05354976c1fc..4eaa28972af2 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)
+ napi_direct &= !xdp_return_frame_no_direct();
page_pool_put_full_page(xa->page_pool, page, napi_direct);
rcu_read_unlock();
break;
--
2.25.1
next reply other threads:[~2021-03-29 7:57 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-29 8:00 Ong Boon Leong [this message]
2021-03-29 15:02 ` [PATCH net 1/1] xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model Jesper Dangaard Brouer
2021-03-29 16:25 ` Toke Høiland-Jørgensen
2021-03-31 8:53 ` Jesper Dangaard Brouer
2021-03-31 12:59 ` Ong, Boon Leong
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