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From: Lorenzo Bianconi <lorenzo@kernel.org>
To: linux-wireless@vger.kernel.org
Cc: lorenzo.bianconi@redhat.com, kuba@kernel.org, nbd@nbd.name,
	matthias_berndt@gmx.de, mozlima@gmail.com
Subject: [PATCH wireless-drivers] mt7601u: fix rx buffer refcounting
Date: Thu, 14 Jan 2021 18:10:52 +0100	[thread overview]
Message-ID: <62b2380c8c2091834cfad05e1059b55f945bd114.1610643952.git.lorenzo@kernel.org> (raw)

Fix the following crash due to erroneous page refcounting:

[   32.445919] BUG: Bad page state in process swapper/1  pfn:11f65a
[   32.447409] page:00000000938f0632 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x11f65a
[   32.449605] flags: 0x8000000000000000()
[   32.450421] raw: 8000000000000000 ffffffff825b0148 ffffea00045ae988 0000000000000000
[   32.451795] raw: 0000000000000000 0000000000000001 00000000ffffff7f 0000000000000000
[   32.452999] page dumped because: nonzero mapcount
[   32.453888] Modules linked in:
[   32.454492] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.11.0-rc2+ #1976
[   32.455695] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-1.fc33 04/01/2014
[   32.457157] Call Trace:
[   32.457636]  <IRQ>
[   32.457993]  dump_stack+0x77/0x97
[   32.458576]  bad_page.cold+0x65/0x96
[   32.459198]  get_page_from_freelist+0x46a/0x11f0
[   32.460008]  __alloc_pages_nodemask+0x10a/0x2b0
[   32.460794]  mt7601u_rx_tasklet+0x651/0x720
[   32.461505]  tasklet_action_common.constprop.0+0x6b/0xd0
[   32.462343]  __do_softirq+0x152/0x46c
[   32.462928]  asm_call_irq_on_stack+0x12/0x20
[   32.463610]  </IRQ>
[   32.463953]  do_softirq_own_stack+0x5b/0x70
[   32.464582]  irq_exit_rcu+0x9f/0xe0
[   32.465028]  common_interrupt+0xae/0x1a0
[   32.465536]  asm_common_interrupt+0x1e/0x40
[   32.466071] RIP: 0010:default_idle+0x18/0x20
[   32.468981] RSP: 0018:ffffc90000077f00 EFLAGS: 00000246
[   32.469648] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
[   32.470550] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff81aac3dd
[   32.471463] RBP: ffff88810022ab00 R08: 0000000000000001 R09: 0000000000000001
[   32.472335] R10: 0000000000000046 R11: 0000000000005aa0 R12: 0000000000000000
[   32.473235] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   32.474139]  ? default_idle_call+0x4d/0x200
[   32.474681]  default_idle_call+0x74/0x200
[   32.475192]  do_idle+0x1d5/0x250
[   32.475612]  cpu_startup_entry+0x19/0x20
[   32.476114]  secondary_startup_64_no_verify+0xb0/0xbb
[   32.476765] Disabling lock debugging due to kernel taint

Fixes: c869f77d6abb ("add mt7601u driver")
Co-developed-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/wireless/mediatek/mt7601u/dma.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt7601u/dma.c b/drivers/net/wireless/mediatek/mt7601u/dma.c
index 5f99054f535b..47710da5b2a5 100644
--- a/drivers/net/wireless/mediatek/mt7601u/dma.c
+++ b/drivers/net/wireless/mediatek/mt7601u/dma.c
@@ -152,8 +152,7 @@ mt7601u_rx_process_entry(struct mt7601u_dev *dev, struct mt7601u_dma_buf_rx *e)
 
 	if (new_p) {
 		/* we have one extra ref from the allocator */
-		__free_pages(e->p, MT_RX_ORDER);
-
+		put_page(e->p);
 		e->p = new_p;
 	}
 }
-- 
2.29.2


             reply	other threads:[~2021-01-14 17:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-14 17:10 Lorenzo Bianconi [this message]
2021-01-14 17:12 ` [PATCH wireless-drivers] mt7601u: fix rx buffer refcounting Jakub Kicinski
2021-01-15  7:05   ` Kalle Valo
2021-01-18 15:22 ` Kalle Valo

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