Hi Jesper, I love your patch! Perhaps something to improve:
[auto build test WARNING on bpf-next/master] url: https://github.com/0day-ci/linux/commits/Jesper-Dangaard-Brouer/bpf-New-approach-for-BPF-MTU-handling-and-enforcement/20201007-000903 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: mips-randconfig-r024-20201005 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 1127662c6dc2a276839c75a42238b11a3ad00f32) 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 # install mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu # https://github.com/0day-ci/linux/commit/2065cee7d6b74c8f1dabae4e4e15999a841e3349 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Jesper-Dangaard-Brouer/bpf-New-approach-for-BPF-MTU-handling-and-enforcement/20201007-000903 git checkout 2065cee7d6b74c8f1dabae4e4e15999a841e3349 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <l...@intel.com> All warnings (new ones prefixed by >>): net/core/dev.c:4176:1: warning: unused label 'drop' drop: ^~~~~ >> net/core/dev.c:4068:7: warning: unused variable 'mtu_check' bool mtu_check = false; ^ net/core/dev.c:4949:1: warning: unused function 'sch_handle_ingress' sch_handle_ingress(struct sk_buff struct packet_type int ^ net/core/dev.c:5094:19: warning: unused function 'nf_ingress' static inline int nf_ingress(struct sk_buff struct packet_type ^ fatal error: error in backend: Nested variants found in inline asm string: ' .set push .set noat .set push .set arch=r4000 .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/cmpxchg.h", .line = 163, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif 1: ll $0, $2 # __cmpxchg_asm bne $0, ${3:z}, 2f .set pop move $$1, ${4:z} .set arch=r4000 sc $$1, $1 beqz $$1, 1b .set pop 2: .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/cmpxchg.h", .line = 163, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif ' clang-12: error: clang frontend command failed with exit code 70 (use -v to see invocation) clang version 12.0.0 (git://gitmirror/llvm_project 1127662c6dc2a276839c75a42238b11a3ad00f32) Target: mipsel-unknown-linux-gnu Thread model: posix InstalledDir: /opt/cross/clang-1127662c6d/bin clang-12: note: diagnostic msg: Makefile arch drivers include kernel net scripts source usr -- >> net/core/dev.c:4068:7: warning: unused variable 'mtu_check' bool mtu_check = false; ^ net/core/dev.c:4176:1: warning: unused label 'drop' drop: ^~~~~ net/core/dev.c:4949:1: warning: unused function 'sch_handle_ingress' sch_handle_ingress(struct sk_buff struct packet_type int ^ net/core/dev.c:5094:19: warning: unused function 'nf_ingress' static inline int nf_ingress(struct sk_buff struct packet_type ^ fatal error: error in backend: Nested variants found in inline asm string: ' .set push .set noat .set push .set arch=r4000 .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/cmpxchg.h", .line = 163, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif 1: ll $0, $2 # __cmpxchg_asm bne $0, ${3:z}, 2f .set pop move $$1, ${4:z} .set arch=r4000 sc $$1, $1 beqz $$1, 1b .set pop 2: .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/cmpxchg.h", .line = 163, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif ' clang-12: error: clang frontend command failed with exit code 70 (use -v to see invocation) clang version 12.0.0 (git://gitmirror/llvm_project 1127662c6dc2a276839c75a42238b11a3ad00f32) Target: mipsel-unknown-linux-gnu Thread model: posix InstalledDir: /opt/cross/clang-1127662c6d/bin clang-12: note: diagnostic msg: Makefile arch drivers include kernel net scripts source usr vim +/mtu_check +4068 net/core/dev.c 4037 4038 /** 4039 * __dev_queue_xmit - transmit a buffer 4040 * @skb: buffer to transmit 4041 * @sb_dev: suboordinate device used for L2 forwarding offload 4042 * 4043 * Queue a buffer for transmission to a network device. The caller must 4044 * have set the device and priority and built the buffer before calling 4045 * this function. The function can be called from an interrupt. 4046 * 4047 * A negative errno code is returned on a failure. A success does not 4048 * guarantee the frame will be transmitted as it may be dropped due 4049 * to congestion or traffic shaping. 4050 * 4051 * ----------------------------------------------------------------------------------- 4052 * I notice this method can also return errors from the queue disciplines, 4053 * including NET_XMIT_DROP, which is a positive value. So, errors can also 4054 * be positive. 4055 * 4056 * Regardless of the return value, the skb is consumed, so it is currently 4057 * difficult to retry a send to this method. (You can bump the ref count 4058 * before sending to hold a reference for retry if you are careful.) 4059 * 4060 * When calling this method, interrupts MUST be enabled. This is because 4061 * the BH enable code must have IRQs enabled so that it will not deadlock. 4062 * --BLG 4063 */ 4064 static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev) 4065 { 4066 struct net_device *dev = skb->dev; 4067 struct netdev_queue *txq; > 4068 bool mtu_check = false; 4069 bool again = false; 4070 struct Qdisc *q; 4071 int rc = -ENOMEM; 4072 4073 skb_reset_mac_header(skb); 4074 4075 if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_SCHED_TSTAMP)) 4076 __skb_tstamp_tx(skb, NULL, skb->sk, SCM_TSTAMP_SCHED); 4077 4078 /* Disable soft irqs for various locks below. Also 4079 * stops preemption for RCU. 4080 */ 4081 rcu_read_lock_bh(); 4082 4083 skb_update_prio(skb); 4084 4085 qdisc_pkt_len_init(skb); 4086 #ifdef CONFIG_NET_CLS_ACT 4087 mtu_check = skb_is_redirected(skb); 4088 skb->tc_at_ingress = 0; 4089 # ifdef CONFIG_NET_EGRESS 4090 if (static_branch_unlikely(&egress_needed_key)) { 4091 unsigned int len_orig = skb->len; 4092 4093 skb = sch_handle_egress(skb, &rc, dev); 4094 if (!skb) 4095 goto out; 4096 /* BPF-prog ran and could have changed packet size beyond MTU */ 4097 if (rc == NET_XMIT_SUCCESS && skb->len > len_orig) 4098 mtu_check = true; 4099 } 4100 # endif 4101 /* MTU-check only happens on "last" net_device in a redirect sequence 4102 * (e.g. above sch_handle_egress can steal SKB and skb_do_redirect it 4103 * either ingress or egress to another device). 4104 */ 4105 if (mtu_check && !is_skb_forwardable(dev, skb)) { 4106 rc = -EMSGSIZE; 4107 goto drop; 4108 } 4109 #endif 4110 /* If device/qdisc don't need skb->dst, release it right now while 4111 * its hot in this cpu cache. 4112 */ 4113 if (dev->priv_flags & IFF_XMIT_DST_RELEASE) 4114 skb_dst_drop(skb); 4115 else 4116 skb_dst_force(skb); 4117 4118 txq = netdev_core_pick_tx(dev, skb, sb_dev); 4119 q = rcu_dereference_bh(txq->qdisc); 4120 4121 trace_net_dev_queue(skb); 4122 if (q->enqueue) { 4123 rc = __dev_xmit_skb(skb, q, dev, txq); 4124 goto out; 4125 } 4126 4127 /* The device has no queue. Common case for software devices: 4128 * loopback, all the sorts of tunnels... 4129 4130 * Really, it is unlikely that netif_tx_lock protection is necessary 4131 * here. (f.e. loopback and IP tunnels are clean ignoring statistics 4132 * counters.) 4133 * However, it is possible, that they rely on protection 4134 * made by us here. 4135 4136 * Check this and shot the lock. It is not prone from deadlocks. 4137 *Either shot noqueue qdisc, it is even simpler 8) 4138 */ 4139 if (dev->flags & IFF_UP) { 4140 int cpu = smp_processor_id(); /* ok because BHs are off */ 4141 4142 if (txq->xmit_lock_owner != cpu) { 4143 if (dev_xmit_recursion()) 4144 goto recursion_alert; 4145 4146 skb = validate_xmit_skb(skb, dev, &again); 4147 if (!skb) 4148 goto out; 4149 4150 HARD_TX_LOCK(dev, txq, cpu); 4151 4152 if (!netif_xmit_stopped(txq)) { 4153 dev_xmit_recursion_inc(); 4154 skb = dev_hard_start_xmit(skb, dev, txq, &rc); 4155 dev_xmit_recursion_dec(); 4156 if (dev_xmit_complete(rc)) { 4157 HARD_TX_UNLOCK(dev, txq); 4158 goto out; 4159 } 4160 } 4161 HARD_TX_UNLOCK(dev, txq); 4162 net_crit_ratelimited("Virtual device %s asks to queue packet!\n", 4163 dev->name); 4164 } else { 4165 /* Recursion is detected! It is possible, 4166 * unfortunately 4167 */ 4168 recursion_alert: 4169 net_crit_ratelimited("Dead loop on virtual device %s, fix it urgently!\n", 4170 dev->name); 4171 } 4172 } 4173 4174 rc = -ENETDOWN; 4175 rcu_read_unlock_bh(); 4176 drop: 4177 atomic_long_inc(&dev->tx_dropped); 4178 kfree_skb_list(skb); 4179 return rc; 4180 out: 4181 rcu_read_unlock_bh(); 4182 return rc; 4183 } 4184 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org
.config.gz
Description: application/gzip
