From: Paolo Abeni <pabeni@redhat.com>
Date: Fri, 30 Jul 2021 18:30:53 +0200
Subject: sk_buff: avoid potentially clearing 'slow_gro' field
Patch-mainline: v5.15-rc1
Git-commit: a432934a30679c0e3c47b87f13e4901bc1a3fc03
References: jsc#PED-1565
If skb_dst_set_noref() is invoked with a NULL dst, the 'slow_gro'
field is cleared, too. That could lead to wrong behavior if
the skb later enters the GRO stage.
Fix the potential issue replacing preserving a non-zero value of
the 'slow_gro' field.
Additionally, fix a comment typo.
Reported-by: Sabrina Dubroca <sd@queasysnail.net>
Reported-by: Jakub Kicinski <kuba@kernel.org>
Fixes: 8a886b142bd0 ("sk_buff: track dst status in slow_gro")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/aa42529252dc8bb02bd42e8629427040d1058537.1627662501.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
include/linux/skbuff.h | 2 +-
net/core/dev.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1009,7 +1009,7 @@ static inline void skb_dst_set(struct sk
static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst)
{
WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
- skb->slow_gro = !!dst;
+ skb->slow_gro |= !!dst;
skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
}
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6020,7 +6020,7 @@ static void gro_list_prepare(const struc
skb_mac_header(skb),
maclen);
- /* in most common scenarions _state is 0
+ /* in most common scenarions 'slow_gro' is 0
* otherwise we are already on some slower paths
* either skip all the infrequent tests altogether or
* avoid trying too hard to skip each of them individually