From 0daf07e527095e64ee8927ce297ab626643e9f51 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 17 Jun 2022 20:47:05 -0700 Subject: raw: convert raw sockets to RCU Using rwlock in networking code is extremely risky. writers can starve if enough readers are constantly grabing the rwlock. I thought rwlock were at fault and sent this patch: https://lkml.org/lkml/2022/6/17/272 But Peter and Linus essentially told me rwlock had to be unfair. We need to get rid of rwlock in networking code. Without this fix, following script triggers soft lockups: for i in {1..48} do ping -f -n -q 127.0.0.1 & sleep 0.1 done Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/raw.h | 11 ++++++++++- include/net/rawv6.h | 1 + 2 files changed, 11 insertions(+), 1 deletion(-) (limited to 'include/net') diff --git a/include/net/raw.h b/include/net/raw.h index 719d3556fc0a..d81eeeb8f1e6 100644 --- a/include/net/raw.h +++ b/include/net/raw.h @@ -33,9 +33,18 @@ int raw_rcv(struct sock *, struct sk_buff *); struct raw_hashinfo { rwlock_t lock; - struct hlist_head ht[RAW_HTABLE_SIZE]; + struct hlist_nulls_head ht[RAW_HTABLE_SIZE]; }; +static inline void raw_hashinfo_init(struct raw_hashinfo *hashinfo) +{ + int i; + + rwlock_init(&hashinfo->lock); + for (i = 0; i < RAW_HTABLE_SIZE; i++) + INIT_HLIST_NULLS_HEAD(&hashinfo->ht[i], i); +} + #ifdef CONFIG_PROC_FS int raw_proc_init(void); void raw_proc_exit(void); diff --git a/include/net/rawv6.h b/include/net/rawv6.h index c48c1298699a..bc70909625f6 100644 --- a/include/net/rawv6.h +++ b/include/net/rawv6.h @@ -3,6 +3,7 @@ #define _NET_RAWV6_H #include +#include extern struct raw_hashinfo raw_v6_hashinfo; bool raw_v6_match(struct net *net, struct sock *sk, unsigned short num, -- cgit v1.2.3-58-ga151