4.17-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Abeni pabeni@redhat.com
[ Upstream commit 6c206b20092a3623184cff9470dba75d21507874 ]
After commit 6b229cf77d68 ("udp: add batching to udp_rmem_release()") the sk_rmem_alloc field does not measure exactly anymore the receive queue length, because we batch the rmem release. The issue is really apparent only after commit 0d4a6608f68c ("udp: do rmem bulk free even if the rx sk queue is empty"): the user space can easily check for an empty socket with not-0 queue length reported by the 'ss' tool or the procfs interface.
We need to use a custom UDP helper to report the correct queue length, taking into account the forward allocation deficit.
Reported-by: trevor.francis@46labs.com Fixes: 6b229cf77d68 ("UDP: add batching to udp_rmem_release()") Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/transp_v6.h | 11 +++++++++-- include/net/udp.h | 5 +++++ net/ipv4/udp.c | 2 +- net/ipv4/udp_diag.c | 2 +- net/ipv6/datagram.c | 6 +++--- net/ipv6/udp.c | 3 ++- 6 files changed, 21 insertions(+), 8 deletions(-)
--- a/include/net/transp_v6.h +++ b/include/net/transp_v6.h @@ -45,8 +45,15 @@ int ip6_datagram_send_ctl(struct net *ne struct flowi6 *fl6, struct ipcm6_cookie *ipc6, struct sockcm_cookie *sockc);
-void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp, - __u16 srcp, __u16 destp, int bucket); +void __ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp, + __u16 srcp, __u16 destp, int rqueue, int bucket); +static inline void +ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp, __u16 srcp, + __u16 destp, int bucket) +{ + __ip6_dgram_sock_seq_show(seq, sp, srcp, destp, sk_rmem_alloc_get(sp), + bucket); +}
#define LOOPBACK4_IPV6 cpu_to_be32(0x7f000006)
--- a/include/net/udp.h +++ b/include/net/udp.h @@ -244,6 +244,11 @@ static inline __be16 udp_flow_src_port(s return htons((((u64) hash * (max - min)) >> 32) + min); }
+static inline int udp_rqueue_get(struct sock *sk) +{ + return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit); +} + /* net/ipv4/udp.c */ void udp_destruct_sock(struct sock *sk); void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len); --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2718,7 +2718,7 @@ static void udp4_format_sock(struct sock " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d", bucket, src, srcp, dest, destp, sp->sk_state, sk_wmem_alloc_get(sp), - sk_rmem_alloc_get(sp), + udp_rqueue_get(sp), 0, 0L, 0, from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)), 0, sock_i_ino(sp), --- a/net/ipv4/udp_diag.c +++ b/net/ipv4/udp_diag.c @@ -163,7 +163,7 @@ static int udp_diag_dump_one(struct sk_b static void udp_diag_get_info(struct sock *sk, struct inet_diag_msg *r, void *info) { - r->idiag_rqueue = sk_rmem_alloc_get(sk); + r->idiag_rqueue = udp_rqueue_get(sk); r->idiag_wqueue = sk_wmem_alloc_get(sk); }
--- a/net/ipv6/datagram.c +++ b/net/ipv6/datagram.c @@ -1019,8 +1019,8 @@ exit_f: } EXPORT_SYMBOL_GPL(ip6_datagram_send_ctl);
-void ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp, - __u16 srcp, __u16 destp, int bucket) +void __ip6_dgram_sock_seq_show(struct seq_file *seq, struct sock *sp, + __u16 srcp, __u16 destp, int rqueue, int bucket) { const struct in6_addr *dest, *src;
@@ -1036,7 +1036,7 @@ void ip6_dgram_sock_seq_show(struct seq_ dest->s6_addr32[2], dest->s6_addr32[3], destp, sp->sk_state, sk_wmem_alloc_get(sp), - sk_rmem_alloc_get(sp), + rqueue, 0, 0L, 0, from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)), 0, --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1475,7 +1475,8 @@ int udp6_seq_show(struct seq_file *seq, struct inet_sock *inet = inet_sk(v); __u16 srcp = ntohs(inet->inet_sport); __u16 destp = ntohs(inet->inet_dport); - ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket); + __ip6_dgram_sock_seq_show(seq, v, srcp, destp, + udp_rqueue_get(v), bucket); } return 0; }