[4.9,20/32] mt7601u: fix rx buffer refcounting

From: Lorenzo Bianconi <lorenzo@kernel.org>

From: Lorenzo Bianconi <lorenzo@kernel.org>

commit d24c790577ef01bfa01da2b131313a38c843a634 upstream.

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>
Acked-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/62b2380c8c2091834cfad05e1059b55f945bd114.1610643952.git.lorenzo@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/mediatek/mt7601u/dma.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Message ID	20210202132942.823782029@linuxfoundation.org
State	Superseded
Headers	show Return-Path: <stable-owner@kernel.org> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, stable@vger.kernel.org, Felix Fietkau <nbd@nbd.name>, Lorenzo Bianconi <lorenzo@kernel.org>, Jakub Kicinski <kubakici@wp.pl>, Kalle Valo <kvalo@codeaurora.org> Subject: [PATCH 4.9 20/32] mt7601u: fix rx buffer refcounting Date: Tue, 2 Feb 2021 14:38:43 +0100 Message-Id: <20210202132942.823782029@linuxfoundation.org> In-Reply-To: <20210202132942.035179752@linuxfoundation.org> References: <20210202132942.035179752@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	None \| expand [4.9,02/32] wext: fix NULL-ptr-dereference with cfg80211s lack of commit() [4.9,03/32] net: usb: qmi_wwan: added support for Thales Cinterion PLSx3 modem family [4.9,04/32] y2038: futex: Move compat implementation into futex.c [4.9,05/32] futex: Move futex exit handling into futex code [4.9,06/32] futex: Replace PF_EXITPIDONE with a state [4.9,07/32] exit/exec: Seperate mm_release() [4.9,08/32] futex: Split futex_mm_release() for exit/exec [4.9,09/32] futex: Set task::futex_state to DEAD right after handling futex exit [4.9,10/32] futex: Mark the begin of futex exit explicitly [4.9,11/32] futex: Sanitize exit state handling [4.9,12/32] futex: Provide state handling for exec() as well [4.9,13/32] futex: Add mutex around futex exit [4.9,14/32] futex: Provide distinct return value when owner is exiting [4.9,15/32] futex: Prevent exit livelock [4.9,16/32] KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in intel_arch_events[] [4.9,17/32] KVM: x86: get smi pending status correctly [4.9,18/32] leds: trigger: fix potential deadlock with libata [4.9,19/32] mt7601u: fix kernel crash unplugging the device [4.9,20/32] mt7601u: fix rx buffer refcounting [4.9,21/32] ARM: imx: build suspend-imx6.S with arm instruction set [4.9,22/32] netfilter: nft_dynset: add timeout extension to template [4.9,23/32] xfrm: Fix oops in xfrm_replay_advance_bmp [4.9,24/32] RDMA/cxgb4: Fix the reported max_recv_sge value [4.9,25/32] iwlwifi: pcie: use jiffies for memory read spin time limit [4.9,26/32] iwlwifi: pcie: reschedule in long-running memory reads [4.9,27/32] mac80211: pause TX while changing interface type [4.9,28/32] can: dev: prevent potential information leak in can_fill_info() [4.9,29/32] iommu/vt-d: Gracefully handle DMAR units with no supported address widths [4.9,30/32] iommu/vt-d: Dont dereference iommu_device if IOMMU_API is not built [4.9,31/32] NFC: fix resource leak when target index is invalid [4.9,32/32] NFC: fix possible resource leak

[4.9,20/32] mt7601u: fix rx buffer refcounting

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