[PATCH 5.4 054/177] brcmfmac: disable PCIe interrupts before bus reset

Greg Kroah-Hartman
2019-12-16T18:16:35Z

From: Rafał Miłecki <rafal@milecki.pl>

commit 5d26a6a6150c486f51ea2aaab33af04db02f63b8 upstream.

Keeping interrupts on could result in brcmfmac freeing some resources
and then IRQ handlers trying to use them. That was obviously a straight
path for crashing a kernel.

Example:
CPU0 CPU1
---- ----
brcmf_pcie_reset
brcmf_pcie_bus_console_read
brcmf_detach
...
brcmf_fweh_detach
brcmf_proto_detach
brcmf_pcie_isr_thread
...
brcmf_proto_msgbuf_rx_trigger
...
drvr->proto->pd
brcmf_pcie_release_irq

[ 363.789218] Unable to handle kernel NULL pointer dereference at virtual address 00000038
[ 363.797339] pgd = c0004000
[ 363.800050] [00000038] *pgd=00000000
[ 363.803635] Internal error: Oops: 17 [#1] SMP ARM
(...)
[ 364.029209] Backtrace:
[ 364.031725] [<bf243838>] (brcmf_proto_msgbuf_rx_trigger [brcmfmac]) from [<bf2471dc>] (brcmf_pcie_isr_thread+0x228/0x274 [brcmfmac])
[ 364.043662] r7:00000001 r6:c8ca0000 r5:00010000 r4:c7b4f800

Fixes: 4684997d9eea ("brcmfmac: reset PCIe bus on a firmware crash")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
@@ -1427,6 +1427,8 @@ static int brcmf_pcie_reset(struct devic
struct brcmf_fw_request *fwreq;
int err;

+ brcmf_pcie_intr_disable(devinfo);
+
brcmf_pcie_bus_console_read(devinfo, true);

brcmf_detach(dev);