From 237312c5e485804417e0f809f948112c3eb7fc96 Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Tue, 15 Oct 2019 17:16:43 +0200 Subject: mt76: refactor cc_lock locking scheme Read busy counters not holding cc_lock spinlock since usb read can't be performed in interrupt context. Move cc_active and cc_rx counters out of cc_lock since they are not modified in interrupt context. Grab cc_lock updating cur_cc_bss_rx in mt76_airtime_report and do not hold rx_lock in mt76_update_survey. Moreover grab mt76 mutex in mt76_get_survey before running mt76_update_survey. This patch fixes the following 'schedule while atomic' [ 291.790866] BUG: scheduling while atomic: iw/2161/0x00000202 [ 291.791002] Preemption disabled at: [ 291.791007] [<0000000000000000>] 0x0 [ 291.791015] CPU: 0 PID: 2161 Comm: iw Tainted: G W 5.4.= 0-rc2-3-ARCH-00104-g9e208aa06c21 #1 [ 291.791017] Hardware name: LENOVO 2349QM6/2349QM6, BIOS G1ETC2WW (2.82=) 08/07/2019 [ 291.791019] Call Trace: [ 291.791042] dump_stack+0x5c/0x80 [ 291.791049] __schedule_bug.cold+0x8e/0x9b [ 291.791055] __schedule+0x5f8/0x770 [ 291.791062] schedule+0x43/0xd0 [ 291.791068] schedule_preempt_disabled+0x14/0x20 [ 291.791074] __mutex_lock.isra.0+0x18a/0x530 [ 291.791099] mt76u_rr+0x1f/0x40 [mt76_usb] [ 291.791113] mt76x02_update_channel+0x22/0x40 [mt76x02_lib] [ 291.791122] mt76_update_survey+0x42/0xe0 [mt76] [ 291.791129] mt76_get_survey+0x2f/0x1b0 [mt76] [ 291.791170] ieee80211_dump_survey+0x5e/0x140 [mac80211] [ 291.791217] nl80211_dump_survey+0x13c/0x2f0 [cfg80211] [ 291.791222] ? __kmalloc_reserve.isra.0+0x2d/0x70 [ 291.791225] ? __alloc_skb+0x96/0x1d0 [ 291.791229] netlink_dump+0x17b/0x370 [ 291.791247] __netlink_dump_start+0x16f/0x1e0 [ 291.791253] genl_family_rcv_msg+0x396/0x410 [ 291.791290] ? nl80211_prepare_wdev_dump+0x1b0/0x1b0 [cfg80211] [ 291.791297] ? _raw_spin_unlock_irqrestore+0x20/0x40 [ 291.791312] ? __wake_up_common_lock+0x8a/0xc0 [ 291.791316] genl_rcv_msg+0x47/0x90 [ 291.791320] ? genl_family_rcv_msg+0x410/0x410 [ 291.791323] netlink_rcv_skb+0x49/0x110 [ 291.791329] genl_rcv+0x24/0x40 [ 291.791333] netlink_unicast+0x171/0x200 [ 291.791340] netlink_sendmsg+0x208/0x3d0 [ 291.791358] sock_sendmsg+0x5e/0x60 [ 291.791361] ___sys_sendmsg+0x2ae/0x330 [ 291.791368] ? filemap_map_pages+0x272/0x390 [ 291.791374] ? _raw_spin_unlock+0x16/0x30 [ 291.791379] ? __handle_mm_fault+0x112f/0x1390 [ 291.791388] __sys_sendmsg+0x59/0xa0 [ 291.791396] do_syscall_64+0x5b/0x1a0 [ 291.791400] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 291.791404] RIP: 0033:0x7f5d0c7f37b7 [ 291.791418] Code: 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 0= 0 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05= <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10 [ 291.791421] RSP: 002b:00007ffe8b5d0538 EFLAGS: 00000246 ORIG_RAX: 0000= 00000000002e [ 291.791426] RAX: ffffffffffffffda RBX: 000055a038e6c390 RCX: 00007f5d0= c7f37b7 [ 291.791430] RDX: 0000000000000000 RSI: 00007ffe8b5d0570 RDI: 000000000= 0000003 [ 291.791434] RBP: 000055a038e718c0 R08: 000055a038e6c02a R09: 000000000= 0000002 [ 291.791438] R10: 000055a03808cb00 R11: 0000000000000246 R12: 000055a03= 8e71780 [ 291.791440] R13: 00007ffe8b5d0570 R14: 000055a038e717d0 R15: 000055a03= 8e718c0 [ 291.791480] NOHZ: local_softirq_pending 202 Fixes: 168aea24f4bb ("mt76: mt76x02u: enable survey support") Tested-by: Markus Theil Signed-off-by: Lorenzo Bianconi Signed-off-by: Felix Fietkau --- drivers/net/wireless/mediatek/mt76/mac80211.c | 29 +++++++++++++----------- drivers/net/wireless/mediatek/mt76/mt76x02_mac.c | 3 +++ 2 files changed, 19 insertions(+), 13 deletions(-) (limited to 'drivers/net/wireless') diff --git a/drivers/net/wireless/mediatek/mt76/mac80211.c b/drivers/net/wireless/mediatek/mt76/mac80211.c index c4eb00d79ffc..4e6f14ca00f2 100644 --- a/drivers/net/wireless/mediatek/mt76/mac80211.c +++ b/drivers/net/wireless/mediatek/mt76/mac80211.c @@ -432,8 +432,6 @@ void mt76_update_survey(struct mt76_dev *dev) if (!test_bit(MT76_STATE_RUNNING, &dev->state)) return; - spin_lock_bh(&dev->cc_lock); - if (dev->drv->update_survey) dev->drv->update_survey(dev); @@ -442,15 +440,11 @@ void mt76_update_survey(struct mt76_dev *dev) dev->survey_time)); dev->survey_time = cur_time; - spin_unlock_bh(&dev->cc_lock); - if (dev->drv->drv_flags & MT_DRV_SW_RX_AIRTIME) { - spin_lock_bh(&dev->rx_lock); - spin_lock(&dev->cc_lock); + spin_lock_bh(&dev->cc_lock); state->cc_bss_rx += dev->cur_cc_bss_rx; dev->cur_cc_bss_rx = 0; - spin_unlock(&dev->cc_lock); - spin_unlock_bh(&dev->rx_lock); + spin_unlock_bh(&dev->cc_lock); } } EXPORT_SYMBOL_GPL(mt76_update_survey); @@ -485,6 +479,7 @@ int mt76_get_survey(struct ieee80211_hw *hw, int idx, struct mt76_channel_state *state; int ret = 0; + mutex_lock(&dev->mutex); if (idx == 0 && dev->drv->update_survey) mt76_update_survey(dev); @@ -494,8 +489,10 @@ int mt76_get_survey(struct ieee80211_hw *hw, int idx, sband = &dev->sband_5g; } - if (idx >= sband->sband.n_channels) - return -ENOENT; + if (idx >= sband->sband.n_channels) { + ret = -ENOENT; + goto out; + } chan = &sband->sband.channels[idx]; state = mt76_channel_state(dev, chan); @@ -511,14 +508,18 @@ int mt76_get_survey(struct ieee80211_hw *hw, int idx, survey->filled |= SURVEY_INFO_TIME_BSS_RX; } - spin_lock_bh(&dev->cc_lock); - survey->time = div_u64(state->cc_active, 1000); survey->time_busy = div_u64(state->cc_busy, 1000); - survey->time_bss_rx = div_u64(state->cc_bss_rx, 1000); survey->time_rx = div_u64(state->cc_rx, 1000); + survey->time = div_u64(state->cc_active, 1000); + + spin_lock_bh(&dev->cc_lock); + survey->time_bss_rx = div_u64(state->cc_bss_rx, 1000); survey->time_tx = div_u64(state->cc_tx, 1000); spin_unlock_bh(&dev->cc_lock); +out: + mutex_unlock(&dev->mutex); + return ret; } EXPORT_SYMBOL_GPL(mt76_get_survey); @@ -622,7 +623,9 @@ mt76_airtime_report(struct mt76_dev *dev, struct mt76_rx_status *status, u32 airtime; airtime = mt76_calc_rx_airtime(dev, status, len); + spin_lock(&dev->cc_lock); dev->cur_cc_bss_rx += airtime; + spin_unlock(&dev->cc_lock); if (!wcid || !wcid->sta) return; diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c index 38329ebca572..4460548f346a 100644 --- a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c @@ -1020,8 +1020,11 @@ void mt76x02_update_channel(struct mt76_dev *mdev) state = mdev->chan_state; state->cc_busy += mt76_rr(dev, MT_CH_BUSY); + + spin_lock_bh(&dev->mt76.cc_lock); state->cc_tx += dev->tx_airtime; dev->tx_airtime = 0; + spin_unlock_bh(&dev->mt76.cc_lock); } EXPORT_SYMBOL_GPL(mt76x02_update_channel); -- cgit v1.2.3