Message ID | 20230403200138.937569-8-john.fastabend@gmail.com (mailing list archive) |
---|---|
State | Superseded |
Delegated to: | BPF |
Headers | show |
Series | bpf sockmap fixes | expand |
Hi John, kernel test robot noticed the following build errors: [auto build test ERROR on bpf/master] url: https://github.com/intel-lab-lkp/linux/commits/John-Fastabend/bpf-sockmap-pass-skb-ownership-through-read_skb/20230404-040431 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master patch link: https://lore.kernel.org/r/20230403200138.937569-8-john.fastabend%40gmail.com patch subject: [PATCH bpf v3 07/12] bpf: sockmap incorrectly handling copied_seq config: sparc64-randconfig-r025-20230403 (https://download.01.org/0day-ci/archive/20230404/202304041013.HATc3V5L-lkp@intel.com/config) compiler: sparc64-linux-gcc (GCC) 12.1.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/fbafbc850ec4ef5aa7e5c39d8133f291ec4c0bb8 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review John-Fastabend/bpf-sockmap-pass-skb-ownership-through-read_skb/20230404-040431 git checkout fbafbc850ec4ef5aa7e5c39d8133f291ec4c0bb8 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sparc64 olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=sparc64 SHELL=/bin/bash net/core/ net/ipv4/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@intel.com> | Link: https://lore.kernel.org/oe-kbuild-all/202304041013.HATc3V5L-lkp@intel.com/ All error/warnings (new ones prefixed by >>): net/core/skmsg.c: In function 'sk_psock_verdict_apply': >> net/core/skmsg.c:1056:17: error: implicit declaration of function 'tcp_eat_skb'; did you mean 'tcp_read_skb'? [-Werror=implicit-function-declaration] 1056 | tcp_eat_skb(psock->sk, skb); | ^~~~~~~~~~~ | tcp_read_skb cc1: some warnings being treated as errors -- >> net/ipv4/tcp_bpf.c:14:6: warning: no previous prototype for 'tcp_eat_skb' [-Wmissing-prototypes] 14 | void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) | ^~~~~~~~~~~ vim +1056 net/core/skmsg.c 986 987 static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb, 988 int verdict) 989 { 990 struct sk_psock_work_state *state; 991 struct sock *sk_other; 992 int err = 0; 993 u32 len, off; 994 995 switch (verdict) { 996 case __SK_PASS: 997 err = -EIO; 998 sk_other = psock->sk; 999 if (sock_flag(sk_other, SOCK_DEAD) || 1000 !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) { 1001 skb_bpf_redirect_clear(skb); 1002 goto out_free; 1003 } 1004 1005 skb_bpf_set_ingress(skb); 1006 1007 /* We need to grab mutex here because in-flight skb is in one of 1008 * the following states: either on ingress_skb, in psock->state 1009 * or being processed by backlog and neither in state->skb and 1010 * ingress_skb may be also empty. The troublesome case is when 1011 * the skb has been dequeued from ingress_skb list or taken from 1012 * state->skb because we can not easily test this case. Maybe we 1013 * could be clever with flags and resolve this but being clever 1014 * got us here in the first place and we note this is done under 1015 * sock lock and backlog conditions mean we are already running 1016 * into ENOMEM or other performance hindering cases so lets do 1017 * the obvious thing and grab the mutex. 1018 */ 1019 mutex_lock(&psock->work_mutex); 1020 state = &psock->work_state; 1021 1022 /* If the queue is empty then we can submit directly 1023 * into the msg queue. If its not empty we have to 1024 * queue work otherwise we may get OOO data. Otherwise, 1025 * if sk_psock_skb_ingress errors will be handled by 1026 * retrying later from workqueue. 1027 */ 1028 if (skb_queue_empty(&psock->ingress_skb) && likely(!state->skb)) { 1029 len = skb->len; 1030 off = 0; 1031 if (skb_bpf_strparser(skb)) { 1032 struct strp_msg *stm = strp_msg(skb); 1033 1034 off = stm->offset; 1035 len = stm->full_len; 1036 } 1037 err = sk_psock_skb_ingress_self(psock, skb, off, len); 1038 } 1039 if (err < 0) { 1040 spin_lock_bh(&psock->ingress_lock); 1041 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) { 1042 skb_queue_tail(&psock->ingress_skb, skb); 1043 schedule_delayed_work(&psock->work, 0); 1044 err = 0; 1045 } 1046 spin_unlock_bh(&psock->ingress_lock); 1047 if (err < 0) { 1048 skb_bpf_redirect_clear(skb); 1049 mutex_unlock(&psock->work_mutex); 1050 goto out_free; 1051 } 1052 } 1053 mutex_unlock(&psock->work_mutex); 1054 break; 1055 case __SK_REDIRECT: > 1056 tcp_eat_skb(psock->sk, skb); 1057 err = sk_psock_skb_redirect(psock, skb); 1058 break; 1059 case __SK_DROP: 1060 default: 1061 out_free: 1062 tcp_eat_skb(psock->sk, skb); 1063 skb_bpf_redirect_clear(skb); 1064 sock_drop(psock->sk, skb); 1065 } 1066 1067 return err; 1068 } 1069
Hi John, kernel test robot noticed the following build errors: [auto build test ERROR on bpf/master] url: https://github.com/intel-lab-lkp/linux/commits/John-Fastabend/bpf-sockmap-pass-skb-ownership-through-read_skb/20230404-040431 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master patch link: https://lore.kernel.org/r/20230403200138.937569-8-john.fastabend%40gmail.com patch subject: [PATCH bpf v3 07/12] bpf: sockmap incorrectly handling copied_seq config: hexagon-randconfig-r041-20230403 (https://download.01.org/0day-ci/archive/20230404/202304041028.XAQryEFM-lkp@intel.com/config) compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/fbafbc850ec4ef5aa7e5c39d8133f291ec4c0bb8 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review John-Fastabend/bpf-sockmap-pass-skb-ownership-through-read_skb/20230404-040431 git checkout fbafbc850ec4ef5aa7e5c39d8133f291ec4c0bb8 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash net/core/ net/ipv4/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot <lkp@intel.com> | Link: https://lore.kernel.org/oe-kbuild-all/202304041028.XAQryEFM-lkp@intel.com/ All error/warnings (new ones prefixed by >>): In file included from net/core/skmsg.c:4: In file included from include/linux/skmsg.h:7: In file included from include/linux/bpf.h:31: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from net/core/skmsg.c:4: In file included from include/linux/skmsg.h:7: In file included from include/linux/bpf.h:31: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from net/core/skmsg.c:4: In file included from include/linux/skmsg.h:7: In file included from include/linux/bpf.h:31: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ >> net/core/skmsg.c:1056:3: error: call to undeclared function 'tcp_eat_skb'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] tcp_eat_skb(psock->sk, skb); ^ net/core/skmsg.c:1056:3: note: did you mean 'tcp_read_skb'? include/net/tcp.h:682:5: note: 'tcp_read_skb' declared here int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor); ^ net/core/skmsg.c:1216:3: error: call to undeclared function 'tcp_eat_skb'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] tcp_eat_skb(sk, skb); ^ 6 warnings and 2 errors generated. -- In file included from net/ipv4/tcp_bpf.c:4: In file included from include/linux/skmsg.h:7: In file included from include/linux/bpf.h:31: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from net/ipv4/tcp_bpf.c:4: In file included from include/linux/skmsg.h:7: In file included from include/linux/bpf.h:31: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from net/ipv4/tcp_bpf.c:4: In file included from include/linux/skmsg.h:7: In file included from include/linux/bpf.h:31: In file included from include/linux/memcontrol.h:13: In file included from include/linux/cgroup.h:26: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ >> net/ipv4/tcp_bpf.c:14:6: warning: no previous prototype for function 'tcp_eat_skb' [-Wmissing-prototypes] void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) ^ net/ipv4/tcp_bpf.c:14:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) ^ static 7 warnings generated. vim +/tcp_eat_skb +1056 net/core/skmsg.c 986 987 static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb, 988 int verdict) 989 { 990 struct sk_psock_work_state *state; 991 struct sock *sk_other; 992 int err = 0; 993 u32 len, off; 994 995 switch (verdict) { 996 case __SK_PASS: 997 err = -EIO; 998 sk_other = psock->sk; 999 if (sock_flag(sk_other, SOCK_DEAD) || 1000 !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) { 1001 skb_bpf_redirect_clear(skb); 1002 goto out_free; 1003 } 1004 1005 skb_bpf_set_ingress(skb); 1006 1007 /* We need to grab mutex here because in-flight skb is in one of 1008 * the following states: either on ingress_skb, in psock->state 1009 * or being processed by backlog and neither in state->skb and 1010 * ingress_skb may be also empty. The troublesome case is when 1011 * the skb has been dequeued from ingress_skb list or taken from 1012 * state->skb because we can not easily test this case. Maybe we 1013 * could be clever with flags and resolve this but being clever 1014 * got us here in the first place and we note this is done under 1015 * sock lock and backlog conditions mean we are already running 1016 * into ENOMEM or other performance hindering cases so lets do 1017 * the obvious thing and grab the mutex. 1018 */ 1019 mutex_lock(&psock->work_mutex); 1020 state = &psock->work_state; 1021 1022 /* If the queue is empty then we can submit directly 1023 * into the msg queue. If its not empty we have to 1024 * queue work otherwise we may get OOO data. Otherwise, 1025 * if sk_psock_skb_ingress errors will be handled by 1026 * retrying later from workqueue. 1027 */ 1028 if (skb_queue_empty(&psock->ingress_skb) && likely(!state->skb)) { 1029 len = skb->len; 1030 off = 0; 1031 if (skb_bpf_strparser(skb)) { 1032 struct strp_msg *stm = strp_msg(skb); 1033 1034 off = stm->offset; 1035 len = stm->full_len; 1036 } 1037 err = sk_psock_skb_ingress_self(psock, skb, off, len); 1038 } 1039 if (err < 0) { 1040 spin_lock_bh(&psock->ingress_lock); 1041 if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) { 1042 skb_queue_tail(&psock->ingress_skb, skb); 1043 schedule_delayed_work(&psock->work, 0); 1044 err = 0; 1045 } 1046 spin_unlock_bh(&psock->ingress_lock); 1047 if (err < 0) { 1048 skb_bpf_redirect_clear(skb); 1049 mutex_unlock(&psock->work_mutex); 1050 goto out_free; 1051 } 1052 } 1053 mutex_unlock(&psock->work_mutex); 1054 break; 1055 case __SK_REDIRECT: > 1056 tcp_eat_skb(psock->sk, skb); 1057 err = sk_psock_skb_redirect(psock, skb); 1058 break; 1059 case __SK_DROP: 1060 default: 1061 out_free: 1062 tcp_eat_skb(psock->sk, skb); 1063 skb_bpf_redirect_clear(skb); 1064 sock_drop(psock->sk, skb); 1065 } 1066 1067 return err; 1068 } 1069
diff --git a/include/net/tcp.h b/include/net/tcp.h index db9f828e9d1e..674044b8bdaf 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1467,6 +1467,8 @@ static inline void tcp_adjust_rcv_ssthresh(struct sock *sk) } void tcp_cleanup_rbuf(struct sock *sk, int copied); +void __tcp_cleanup_rbuf(struct sock *sk, int copied); + /* We provision sk_rcvbuf around 200% of sk_rcvlowat. * If 87.5 % (7/8) of the space has been consumed, we want to override @@ -2321,6 +2323,7 @@ struct sk_psock; struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock); int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore); void tcp_bpf_clone(const struct sock *sk, struct sock *newsk); +void tcp_eat_skb(struct sock *sk, struct sk_buff *skb); #endif /* CONFIG_BPF_SYSCALL */ int tcp_bpf_sendmsg_redir(struct sock *sk, bool ingress, diff --git a/net/core/skmsg.c b/net/core/skmsg.c index a2e83d2aacf8..69983f40fbec 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -1053,11 +1053,14 @@ static int sk_psock_verdict_apply(struct sk_psock *psock, struct sk_buff *skb, mutex_unlock(&psock->work_mutex); break; case __SK_REDIRECT: + tcp_eat_skb(psock->sk, skb); err = sk_psock_skb_redirect(psock, skb); break; case __SK_DROP: default: out_free: + tcp_eat_skb(psock->sk, skb); + skb_bpf_redirect_clear(skb); sock_drop(psock->sk, skb); } @@ -1102,8 +1105,7 @@ static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb) skb_dst_drop(skb); skb_bpf_redirect_clear(skb); ret = bpf_prog_run_pin_on_cpu(prog, skb); - if (ret == SK_PASS) - skb_bpf_set_strparser(skb); + skb_bpf_set_strparser(skb); ret = sk_psock_map_verd(ret, skb_bpf_redirect_fetch(skb)); skb->sk = NULL; } @@ -1211,6 +1213,7 @@ static int sk_psock_verdict_recv(struct sock *sk, struct sk_buff *skb) psock = sk_psock(sk); if (unlikely(!psock)) { len = 0; + tcp_eat_skb(sk, skb); sock_drop(sk, skb); goto out; } diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 1be305e3d3c7..5610f8341b38 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1568,7 +1568,7 @@ static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len) * calculation of whether or not we must ACK for the sake of * a window update. */ -static void __tcp_cleanup_rbuf(struct sock *sk, int copied) +void __tcp_cleanup_rbuf(struct sock *sk, int copied) { struct tcp_sock *tp = tcp_sk(sk); bool time_to_ack = false; @@ -1783,14 +1783,6 @@ int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor) break; } } - WRITE_ONCE(tp->copied_seq, seq); - - tcp_rcv_space_adjust(sk); - - /* Clean up data we have read: This will do ACK frames. */ - if (copied > 0) - __tcp_cleanup_rbuf(sk, copied); - return copied; } EXPORT_SYMBOL(tcp_read_skb); diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index ae6c7130551c..9e94864ce130 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -11,6 +11,24 @@ #include <net/inet_common.h> #include <net/tls.h> +void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) +{ + struct tcp_sock *tcp; + int copied; + + if (!skb || !skb->len || !sk_is_tcp(sk)) + return; + + if (skb_bpf_strparser(skb)) + return; + + tcp = tcp_sk(sk); + copied = tcp->copied_seq + skb->len; + WRITE_ONCE(tcp->copied_seq, copied); + tcp_rcv_space_adjust(sk); + __tcp_cleanup_rbuf(sk, skb->len); +} + static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock, struct sk_msg *msg, u32 apply_bytes, int flags) { @@ -198,8 +216,10 @@ static int tcp_bpf_recvmsg_parser(struct sock *sk, int flags, int *addr_len) { + struct tcp_sock *tcp = tcp_sk(sk); + u32 seq = tcp->copied_seq; struct sk_psock *psock; - int copied; + int copied = 0; if (unlikely(flags & MSG_ERRQUEUE)) return inet_recv_error(sk, msg, len, addr_len); @@ -244,9 +264,11 @@ static int tcp_bpf_recvmsg_parser(struct sock *sk, if (is_fin) { copied = 0; + seq++; goto out; } } + seq += copied; if (!copied) { long timeo; int data; @@ -284,6 +306,10 @@ static int tcp_bpf_recvmsg_parser(struct sock *sk, copied = -EAGAIN; } out: + WRITE_ONCE(tcp->copied_seq, seq); + tcp_rcv_space_adjust(sk); + if (copied > 0) + __tcp_cleanup_rbuf(sk, copied); release_sock(sk); sk_psock_put(sk, psock); return copied;
The read_skb() logic is incrementing the tcp->copied_seq which is used for among other things calculating how many outstanding bytes can be read by the application. This results in application errors, if the application does an ioctl(FIONREAD) we return zero because this is calculated from the copied_seq value. To fix this we move tcp->copied_seq accounting into the recv handler so that we update these when the recvmsg() hook is called and data is in fact copied into user buffers. This gives an accurate FIONREAD value as expected and improves ACK handling. Before we were calling the tcp_rcv_space_adjust() which would update 'number of bytes copied to user in last RTT' which is wrong for programs returning SK_PASS. The bytes are only copied to the user when recvmsg is handled. Doing the fix for recvmsg is straightforward, but fixing redirect and SK_DROP pkts is a bit tricker. Build a tcp_psock_eat() helper and then call this from skmsg handlers. This fixes another issue where a broken socket with a BPF program doing a resubmit could hang the receiver. This happened because although read_skb() consumed the skb through sock_drop() it did not update the copied_seq. Now if a single reccv socket is redirecting to many sockets (for example for lb) the receiver sk will be hung even though we might expect it to continue. The hang comes from not updating the copied_seq numbers and memory pressure resulting from that. We have a slight layer problem of calling tcp_eat_skb even if its not a TCP socket. To fix we could refactor and create per type receiver handlers. I decided this is more work than we want in the fix and we already have some small tweaks depending on caller that use the helper skb_bpf_strparser(). So we extend that a bit and always set the strparser bit when it is in use and then we can gate the seq_copied updates on this. Fixes: 04919bed948dc ("tcp: Introduce tcp_read_skb()") Signed-off-by: John Fastabend <john.fastabend@gmail.com> --- include/net/tcp.h | 3 +++ net/core/skmsg.c | 7 +++++-- net/ipv4/tcp.c | 10 +--------- net/ipv4/tcp_bpf.c | 28 +++++++++++++++++++++++++++- 4 files changed, 36 insertions(+), 12 deletions(-)