From 46b1c18f9deb326a7e18348e668e4c7ab7c7458b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 28 Feb 2019 12:55:43 -0800 Subject: net: sched: put back q.qlen into a single location In the series fc8b81a5981f ("Merge branch 'lockless-qdisc-series'") John made the assumption that the data path had no need to read the qdisc qlen (number of packets in the qdisc). It is true when pfifo_fast is used as the root qdisc, or as direct MQ/MQPRIO children. But pfifo_fast can be used as leaf in class full qdiscs, and existing logic needs to access the child qlen in an efficient way. HTB breaks badly, since it uses cl->leaf.q->q.qlen in : htb_activate() -> WARN_ON() htb_dequeue_tree() to decide if a class can be htb_deactivated when it has no more packets. HFSC, DRR, CBQ, QFQ have similar issues, and some calls to qdisc_tree_reduce_backlog() also read q.qlen directly. Using qdisc_qlen_sum() (which iterates over all possible cpus) in the data path is a non starter. It seems we have to put back qlen in a central location, at least for stable kernels. For all qdisc but pfifo_fast, qlen is guarded by the qdisc lock, so the existing q.qlen{++|--} are correct. For 'lockless' qdisc (pfifo_fast so far), we need to use atomic_{inc|dec}() because the spinlock might be not held (for example from pfifo_fast_enqueue() and pfifo_fast_dequeue()) This patch adds atomic_qlen (in the same location than qlen) and renames the following helpers, since we want to express they can be used without qdisc lock, and that qlen is no longer percpu. - qdisc_qstats_cpu_qlen_dec -> qdisc_qstats_atomic_qlen_dec() - qdisc_qstats_cpu_qlen_inc -> qdisc_qstats_atomic_qlen_inc() Later (net-next) we might revert this patch by tracking all these qlen uses and replace them by a more efficient method (not having to access a precise qlen, but an empty/non_empty status that might be less expensive to maintain/track). Another possibility is to have a legacy pfifo_fast version that would be used when used a a child qdisc, since the parent qdisc needs a spinlock anyway. But then, future lockless qdiscs would also have the same problem. Fixes: 7e66016f2c65 ("net: sched: helpers to sum qlen and qlen for per cpu logic") Signed-off-by: Eric Dumazet Cc: John Fastabend Cc: Jamal Hadi Salim Cc: Cong Wang Cc: Jiri Pirko Signed-off-by: David S. Miller --- net/core/gen_stats.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'net/core') diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c index 9bf1b9ad1780..ac679f74ba47 100644 --- a/net/core/gen_stats.c +++ b/net/core/gen_stats.c @@ -291,7 +291,6 @@ __gnet_stats_copy_queue_cpu(struct gnet_stats_queue *qstats, for_each_possible_cpu(i) { const struct gnet_stats_queue *qcpu = per_cpu_ptr(q, i); - qstats->qlen = 0; qstats->backlog += qcpu->backlog; qstats->drops += qcpu->drops; qstats->requeues += qcpu->requeues; @@ -307,7 +306,6 @@ void __gnet_stats_copy_queue(struct gnet_stats_queue *qstats, if (cpu) { __gnet_stats_copy_queue_cpu(qstats, cpu); } else { - qstats->qlen = q->qlen; qstats->backlog = q->backlog; qstats->drops = q->drops; qstats->requeues = q->requeues; -- cgit v1.2.3 From 895a5e96dbd6386c8e78e5b78e067dcc67b7f0ab Mon Sep 17 00:00:00 2001 From: YueHaibing Date: Sat, 2 Mar 2019 10:34:55 +0800 Subject: net-sysfs: Fix mem leak in netdev_register_kobject syzkaller report this: BUG: memory leak unreferenced object 0xffff88837a71a500 (size 256): comm "syz-executor.2", pid 9770, jiffies 4297825125 (age 17.843s) hex dump (first 32 bytes): 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... ff ff ff ff ff ff ff ff 20 c0 ef 86 ff ff ff ff ........ ....... backtrace: [<00000000db12624b>] netdev_register_kobject+0x124/0x2e0 net/core/net-sysfs.c:1751 [<00000000dc49a994>] register_netdevice+0xcc1/0x1270 net/core/dev.c:8516 [<00000000e5f3fea0>] tun_set_iff drivers/net/tun.c:2649 [inline] [<00000000e5f3fea0>] __tun_chr_ioctl+0x2218/0x3d20 drivers/net/tun.c:2883 [<000000001b8ac127>] vfs_ioctl fs/ioctl.c:46 [inline] [<000000001b8ac127>] do_vfs_ioctl+0x1a5/0x10e0 fs/ioctl.c:690 [<0000000079b269f8>] ksys_ioctl+0x89/0xa0 fs/ioctl.c:705 [<00000000de649beb>] __do_sys_ioctl fs/ioctl.c:712 [inline] [<00000000de649beb>] __se_sys_ioctl fs/ioctl.c:710 [inline] [<00000000de649beb>] __x64_sys_ioctl+0x74/0xb0 fs/ioctl.c:710 [<000000007ebded1e>] do_syscall_64+0xc8/0x580 arch/x86/entry/common.c:290 [<00000000db315d36>] entry_SYSCALL_64_after_hwframe+0x49/0xbe [<00000000115be9bb>] 0xffffffffffffffff It should call kset_unregister to free 'dev->queues_kset' in error path of register_queue_kobjects, otherwise will cause a mem leak. Reported-by: Hulk Robot Fixes: 1d24eb4815d1 ("xps: Transmit Packet Steering") Signed-off-by: YueHaibing Signed-off-by: David S. Miller --- net/core/net-sysfs.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/core') diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index ff9fd2bb4ce4..73ad7607dcd1 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1547,6 +1547,9 @@ static int register_queue_kobjects(struct net_device *dev) error: netdev_queue_update_kobjects(dev, txq, 0); net_rx_queue_update_kobjects(dev, rxq, 0); +#ifdef CONFIG_SYSFS + kset_unregister(dev->queues_kset); +#endif return error; } -- cgit v1.2.3