lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:   Fri, 10 Aug 2018 11:28:02 +0200
From:   Björn Töpel <>
Cc:     Björn Töpel <>,,,
Subject: [PATCH bpf] Revert "xdp: add NULL pointer check in __xdp_return()"

From: Björn Töpel <>

This reverts commit 36e0f12bbfd3016f495904b35e41c5711707509f.

The reverted commit adds a WARN to check against NULL entries in the
mem_id_ht rhashtable. Any kernel path implementing the XDP (generic or
driver) fast path is required to make a paired
xdp_rxq_info_reg/xdp_rxq_info_unreg call for proper function. In
addition, a driver using a different allocation scheme than the
default MEM_TYPE_PAGE_SHARED is required to additionally call

For MEM_TYPE_ZERO_COPY, an xdp_rxq_info_reg_mem_model call ensures
that the mem_id_ht rhashtable has a properly inserted allocator id. If
not, this would be a driver bug. A NULL pointer kernel OOPS is
preferred to the WARN.

Suggested-by: Jesper Dangaard Brouer <>
Signed-off-by: Björn Töpel <>
 net/core/xdp.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 6771f1855b96..9d1f22072d5d 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -345,8 +345,7 @@ 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);
-		if (!WARN_ON_ONCE(!xa))
-			xa->zc_alloc->free(xa->zc_alloc, handle);
+		xa->zc_alloc->free(xa->zc_alloc, handle);
 		/* Not possible, checked in xdp_rxq_info_reg_mem_model() */

Powered by blists - more mailing lists