diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.14/950-0207-dwc_otg-add-smp_mb-to-prevent-driver-state-corruptio.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.14/950-0207-dwc_otg-add-smp_mb-to-prevent-driver-state-corruptio.patch | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.14/950-0207-dwc_otg-add-smp_mb-to-prevent-driver-state-corruptio.patch b/target/linux/brcm2708/patches-4.14/950-0207-dwc_otg-add-smp_mb-to-prevent-driver-state-corruptio.patch new file mode 100644 index 0000000000..7e49003c2d --- /dev/null +++ b/target/linux/brcm2708/patches-4.14/950-0207-dwc_otg-add-smp_mb-to-prevent-driver-state-corruptio.patch @@ -0,0 +1,45 @@ +From efdde709efccc4f95c7641eea8960dbc31fc58b5 Mon Sep 17 00:00:00 2001 +From: P33M <p33m@github.com> +Date: Thu, 15 Feb 2018 11:22:44 +0000 +Subject: [PATCH 207/454] dwc_otg: add smp_mb() to prevent driver state + corruption on boot + +Occasional crashes have been seen where the FIQ code dereferences +invalid/random pointers immediately after being set up, leading to +panic on boot. + +The crash occurs as the FIQ code races against hcd_init_fiq() and +the hcd_init_fiq() code races against the outstanding memory stores +from dwc_otg_hcd_init(). Use explicit barriers after touching +driver state. +--- + drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c | 11 ++++++++++- + 1 file changed, 10 insertions(+), 1 deletion(-) + +--- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c ++++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_linux.c +@@ -519,6 +519,11 @@ static void hcd_init_fiq(void *cookie) + DWC_ERROR("Can't get FIQ irq"); + return; + } ++ /* ++ * We could take an interrupt immediately after enabling the FIQ. ++ * Ensure coherency of hcd->fiq_state. ++ */ ++ smp_mb(); + enable_fiq(irq); + local_fiq_enable(); + #endif +@@ -598,7 +603,11 @@ int hcd_init(dwc_bus_dev_t *_dev) + + if (fiq_enable) { + if (num_online_cpus() > 1) { +- /* bcm2709: can run the FIQ on a separate core to IRQs */ ++ /* ++ * bcm2709: can run the FIQ on a separate core to IRQs. ++ * Ensure driver state is visible to other cores before setting up the FIQ. ++ */ ++ smp_mb(); + smp_call_function_single(1, hcd_init_fiq, otg_dev, 1); + } else { + smp_call_function_single(0, hcd_init_fiq, otg_dev, 1); |