From 481bb0432414f790066205fe77226b7d1877385d Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Wed, 26 Sep 2018 13:07:39 +0200 Subject: [PATCH] mt76: usb: make rx page_frag_cache access atomic Add rx_page_lock spinlock in order to make rx page fragment access atomic. This patch fixes the following crash that occasionally occurs during module loading/unloading BUG: unable to handle kernel paging request at ffff9f8322e19000 PGD 27ba01067 P4D 27ba01067 PUD 27ddba063 PMD 263b35063 PTE 8000000262e19061 Oops: 0003 [#1] SMP PTI CPU: 2 PID: 1766 Comm: systemd-udevd Not tainted 4.19.0-rc5+ #6 Hardware name: ASUSTeK COMPUTER INC. ESC2000 G2/Z9PE-D8 WS, BIOS 0405 03/19/2012 RIP: 0010:__memcpy+0x12/0x20 RSP: 0018:ffffba13849b3ad8 EFLAGS: 00010246 RAX: ffff9f8322e17004 RBX: 00000000000038f0 RCX: 000000000000031f RDX: 0000000000000000 RSI: ffffba13844cf058 RDI: ffff9f8322e18ffc RBP: 0000000000010c6c R08: 0000000000000000 R09: 0000607ec0000000 R10: 0000000000000003 R11: 0000000000003e2e R12: ffff9f8324cd9540 R13: 0000000000000000 R14: ffffba13849b3b30 R15: ffff9f8322e17000 FS: 00007fadec85b880(0000) GS:ffff9f833fa80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff9f8322e19000 CR3: 0000000263428001 CR4: 00000000000606e0 Call Trace: mt76x02u_mcu_fw_send_data+0x16c/0x270 [mt76x02_usb] mt76x0u_probe+0x35a/0x598 [mt76x0u] usb_probe_interface+0x113/0x310 really_probe+0x1c8/0x400 driver_probe_device+0x5c/0x130 __driver_attach+0xec/0x110 bus_for_each_dev+0x50/0x90 bus_add_driver+0x1c0/0x280 driver_register+0x5b/0xe0 usb_register_driver+0x7c/0x140 do_one_initcall+0x44/0x19b do_init_module+0x5a/0x210 load_module+0x175c/0x1bc0 __do_sys_finit_module+0x97/0xc0 do_syscall_64+0x3f/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fadeb6f1809 RSP: 002b:00007ffe548f9f38 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 00007fadebdf0d89 RCX: 00007fadeb6f1809 RDX: 0000000000000000 RSI: 00007fadebdf0d89 RDI: 0000000000000006 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000006 R11: 0000000000000246 R12: 0000560b9ef58ab0 R13: 0000560b9ef29800 R14: 0000560b9ef59040 R15: 0000000000020000 Fixes: c12128ce44b0 ("mt76: use a per rx queue page fragment cache") Reported-by: Stanislaw Gruszka Tested-by: Stanislaw Gruszka Signed-off-by: Lorenzo Bianconi Signed-off-by: Felix Fietkau --- drivers/net/wireless/mediatek/mt76/mt76.h | 1 + drivers/net/wireless/mediatek/mt76/mt76x0/usb.c | 4 ++-- drivers/net/wireless/mediatek/mt76/mt76x2u_init.c | 8 ++++---- drivers/net/wireless/mediatek/mt76/usb.c | 8 +++++++- 4 files changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h index 15a5b0c89d86..8031360a6592 100644 --- a/drivers/net/wireless/mediatek/mt76/mt76.h +++ b/drivers/net/wireless/mediatek/mt76/mt76.h @@ -122,6 +122,7 @@ struct mt76_queue { dma_addr_t desc_dma; struct sk_buff *rx_head; struct page_frag_cache rx_page; + spinlock_t rx_page_lock; }; struct mt76_mcu_ops { diff --git a/drivers/net/wireless/mediatek/mt76/mt76x0/usb.c b/drivers/net/wireless/mediatek/mt76/mt76x0/usb.c index 76d607f73758..7647d84e59f5 100644 --- a/drivers/net/wireless/mediatek/mt76/mt76x0/usb.c +++ b/drivers/net/wireless/mediatek/mt76/mt76x0/usb.c @@ -249,11 +249,11 @@ static int mt76x0u_probe(struct usb_interface *usb_intf, if (!(mt76_rr(dev, MT_EFUSE_CTRL) & MT_EFUSE_CTRL_SEL)) dev_warn(dev->mt76.dev, "Warning: eFUSE not present\n"); - ret = mt76u_mcu_init_rx(&dev->mt76); + ret = mt76u_alloc_queues(&dev->mt76); if (ret < 0) goto err; - ret = mt76u_alloc_queues(&dev->mt76); + ret = mt76u_mcu_init_rx(&dev->mt76); if (ret < 0) goto err; diff --git a/drivers/net/wireless/mediatek/mt76/mt76x2u_init.c b/drivers/net/wireless/mediatek/mt76/mt76x2u_init.c index 7a9ebc8985f2..9ba029451f8a 100644 --- a/drivers/net/wireless/mediatek/mt76/mt76x2u_init.c +++ b/drivers/net/wireless/mediatek/mt76/mt76x2u_init.c @@ -264,14 +264,14 @@ int mt76x2u_register_device(struct mt76x2_dev *dev) if (err < 0) return err; - err = mt76u_mcu_init_rx(&dev->mt76); - if (err < 0) - return err; - err = mt76u_alloc_queues(&dev->mt76); if (err < 0) goto fail; + err = mt76u_mcu_init_rx(&dev->mt76); + if (err < 0) + return err; + err = mt76x2u_init_hardware(dev); if (err < 0) goto fail; diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c index 03dee4762c69..de7785c4f6af 100644 --- a/drivers/net/wireless/mediatek/mt76/usb.c +++ b/drivers/net/wireless/mediatek/mt76/usb.c @@ -280,6 +280,7 @@ mt76u_fill_rx_sg(struct mt76_dev *dev, struct mt76u_buf *buf, struct urb *urb = buf->urb; int i; + spin_lock_bh(&q->rx_page_lock); for (i = 0; i < nsgs; i++) { struct page *page; void *data; @@ -293,6 +294,7 @@ mt76u_fill_rx_sg(struct mt76_dev *dev, struct mt76u_buf *buf, offset = data - page_address(page); sg_set_page(&urb->sg[i], page, sglen, offset); } + spin_unlock_bh(&q->rx_page_lock); if (i < nsgs) { int j; @@ -521,6 +523,7 @@ static int mt76u_alloc_rx(struct mt76_dev *dev) struct mt76_queue *q = &dev->q_rx[MT_RXQ_MAIN]; int i, err, nsgs; + spin_lock_init(&q->rx_page_lock); spin_lock_init(&q->lock); q->entry = devm_kzalloc(dev->dev, MT_NUM_RX_ENTRIES * sizeof(*q->entry), @@ -558,12 +561,15 @@ static void mt76u_free_rx(struct mt76_dev *dev) for (i = 0; i < q->ndesc; i++) mt76u_buf_free(&q->entry[i].ubuf); + spin_lock_bh(&q->rx_page_lock); if (!q->rx_page.va) - return; + goto out; page = virt_to_page(q->rx_page.va); __page_frag_cache_drain(page, q->rx_page.pagecnt_bias); memset(&q->rx_page, 0, sizeof(q->rx_page)); +out: + spin_unlock_bh(&q->rx_page_lock); } static void mt76u_stop_rx(struct mt76_dev *dev) -- 2.45.2