> 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'
>
Felix please hold on with this patch since I spotted an issue. cc_lock needs to
be taken disabling bh in mt76_update_survey(). I will post a v2. Sorry for the
noise.
Regards,
Lorenzo
> [ 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 <markus.theil@xxxxxxxxxxxxx>
> Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> ---
> drivers/net/wireless/mediatek/mt76/mac80211.c | 25 +++++++++++--------
> .../net/wireless/mediatek/mt76/mt76x02_mac.c | 3 +++
> 2 files changed, 17 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mac80211.c b/drivers/net/wireless/mediatek/mt76/mac80211.c
> index a962abce98f8..f2d2d2a3e88e 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);
> 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);
> }
> }
> 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 41f7c01045b8..2c0bd9aa1987 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mac.c
> @@ -1024,8 +1024,11 @@ 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);
>
> --
> 2.21.0
>
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