From c24498c6827b71f80fecc9fb1b70a792053d41a9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 27 Sep 2018 09:31:51 -0700 Subject: netpoll: do not test NAPI_STATE_SCHED in poll_one_napi() Since we do no longer require NAPI drivers to provide an ndo_poll_controller(), napi_schedule() has not been done before poll_one_napi() invocation. So testing NAPI_STATE_SCHED is likely to cause early returns. While we are at it, remove outdated comment. Note to future bisections : This change might surface prior bugs in drivers. See commit 73f21c653f93 ("bnxt_en: Fix TX timeout during netpoll.") for one occurrence. Fixes: ac3d9dd034e5 ("netpoll: make ndo_poll_controller() optional") Signed-off-by: Eric Dumazet Tested-by: Song Liu Cc: Michael Chan Signed-off-by: David S. Miller --- net/core/netpoll.c | 20 +------------------- 1 file changed, 1 insertion(+), 19 deletions(-) (limited to 'net/core/netpoll.c') diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 3219a2932463..3ae899805f8b 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -135,27 +135,9 @@ static void queue_process(struct work_struct *work) } } -/* - * Check whether delayed processing was scheduled for our NIC. If so, - * we attempt to grab the poll lock and use ->poll() to pump the card. - * If this fails, either we've recursed in ->poll() or it's already - * running on another CPU. - * - * Note: we don't mask interrupts with this lock because we're using - * trylock here and interrupts are already disabled in the softirq - * case. Further, we test the poll_owner to avoid recursion on UP - * systems where the lock doesn't exist. - */ static void poll_one_napi(struct napi_struct *napi) { - int work = 0; - - /* net_rx_action's ->poll() invocations and our's are - * synchronized by this test which is only made while - * holding the napi->poll_lock. - */ - if (!test_bit(NAPI_STATE_SCHED, &napi->state)) - return; + int work; /* If we set this bit but see that it has already been set, * that indicates that napi has been disabled and we need -- cgit v1.2.3 From 6fe9487892b32cb1c8b8b0d552ed7222a527fe30 Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Fri, 28 Sep 2018 16:26:08 -0400 Subject: bond: take rcu lock in netpoll_send_skb_on_dev The bonding driver lacks the rcu lock when it calls down into netdev_lower_get_next_private_rcu from bond_poll_controller, which results in a trace like: WARNING: CPU: 2 PID: 179 at net/core/dev.c:6567 netdev_lower_get_next_private_rcu+0x34/0x40 CPU: 2 PID: 179 Comm: kworker/u16:15 Not tainted 4.19.0-rc5-backup+ #1 Workqueue: bond0 bond_mii_monitor RIP: 0010:netdev_lower_get_next_private_rcu+0x34/0x40 Code: 48 89 fb e8 fe 29 63 ff 85 c0 74 1e 48 8b 45 00 48 81 c3 c0 00 00 00 48 8b 00 48 39 d8 74 0f 48 89 45 00 48 8b 40 f8 5b 5d c3 <0f> 0b eb de 31 c0 eb f5 0f 1f 40 00 0f 1f 44 00 00 48 8> RSP: 0018:ffffc9000087fa68 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff880429614560 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 00000000ffffffff RDI: ffffffffa184ada0 RBP: ffffc9000087fa80 R08: 0000000000000001 R09: 0000000000000000 R10: ffffc9000087f9f0 R11: ffff880429798040 R12: ffff8804289d5980 R13: ffffffffa1511f60 R14: 00000000000000c8 R15: 00000000ffffffff FS: 0000000000000000(0000) GS:ffff88042f880000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4b78fce180 CR3: 000000018180f006 CR4: 00000000001606e0 Call Trace: bond_poll_controller+0x52/0x170 netpoll_poll_dev+0x79/0x290 netpoll_send_skb_on_dev+0x158/0x2c0 netpoll_send_udp+0x2d5/0x430 write_ext_msg+0x1e0/0x210 console_unlock+0x3c4/0x630 vprintk_emit+0xfa/0x2f0 printk+0x52/0x6e ? __netdev_printk+0x12b/0x220 netdev_info+0x64/0x80 ? bond_3ad_set_carrier+0xe9/0x180 bond_select_active_slave+0x1fc/0x310 bond_mii_monitor+0x709/0x9b0 process_one_work+0x221/0x5e0 worker_thread+0x4f/0x3b0 kthread+0x100/0x140 ? process_one_work+0x5e0/0x5e0 ? kthread_delayed_work_timer_fn+0x90/0x90 ret_from_fork+0x24/0x30 We're also doing rcu dereferences a layer up in netpoll_send_skb_on_dev before we call down into netpoll_poll_dev, so just take the lock there. Suggested-by: Cong Wang Signed-off-by: Dave Jones Signed-off-by: David S. Miller --- net/core/netpoll.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/core/netpoll.c') diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 3ae899805f8b..de1d1ba92f2d 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -312,6 +312,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb, /* It is up to the caller to keep npinfo alive. */ struct netpoll_info *npinfo; + rcu_read_lock_bh(); lockdep_assert_irqs_disabled(); npinfo = rcu_dereference_bh(np->dev->npinfo); @@ -356,6 +357,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb, skb_queue_tail(&npinfo->txq, skb); schedule_delayed_work(&npinfo->tx_work,0); } + rcu_read_unlock_bh(); } EXPORT_SYMBOL(netpoll_send_skb_on_dev); -- cgit v1.2.3