On Mon, May 20, 2024 at 10:53:57AM -0400, Sean Anderson wrote:
MSGF_LEG_MASK is laid out with INTA in bit 0, INTB in bit 1, INTC in bit 2, and INTD in bit 3. Hardware IRQ numbers start at 0, and we register PCI_NUM_INTX irqs. So to enable INTA (aka hwirq 0) we should set bit 0. Remove the subtraction of one. This fixes the following UBSAN error:
Thanks for these details!
I guess UBSAN == "undefined behavior sanitizer", right? That sounds like an easy way to find this but not the way users are likely to find it.
I assume users would notice spurious and missing interrupts, e.g., a driver that tried to enable INTB would have actually enabled INTA, so we'd see spurious INTA interrupts and the driver would never see the INTB it expected.
And a driver that tried to enable INTA would never see that interrupt, and we might not set any bit in MSGF_LEG_MASK?
I think the normal way people would trip over this, i.e., spurious and missing INTx interrupts, is the important thing to mention here.
[ 5.037483] ================================================================================ [ 5.046260] UBSAN: shift-out-of-bounds in ../drivers/pci/controller/pcie-xilinx-nwl.c:389:11 [ 5.054983] shift exponent 18446744073709551615 is too large for 32-bit type 'int' [ 5.062813] CPU: 1 PID: 61 Comm: kworker/u10:1 Not tainted 6.6.20+ #268 [ 5.070008] Hardware name: xlnx,zynqmp (DT) [ 5.074348] Workqueue: events_unbound deferred_probe_work_func [ 5.080410] Call trace: [ 5.082958] dump_backtrace (arch/arm64/kernel/stacktrace.c:235) [ 5.086850] show_stack (arch/arm64/kernel/stacktrace.c:242) [ 5.090292] dump_stack_lvl (lib/dump_stack.c:107) [ 5.094095] dump_stack (lib/dump_stack.c:114) [ 5.097540] __ubsan_handle_shift_out_of_bounds (lib/ubsan.c:218 lib/ubsan.c:387) [ 5.103227] nwl_unmask_leg_irq (drivers/pci/controller/pcie-xilinx-nwl.c:389 (discriminator 1)) [ 5.107386] irq_enable (kernel/irq/internals.h:234 kernel/irq/chip.c:170 kernel/irq/chip.c:439 kernel/irq/chip.c:432 kernel/irq/chip.c:345) [ 5.110838] __irq_startup (kernel/irq/internals.h:239 kernel/irq/chip.c:180 kernel/irq/chip.c:250) [ 5.114552] irq_startup (kernel/irq/chip.c:270) [ 5.118266] __setup_irq (kernel/irq/manage.c:1800) [ 5.121982] request_threaded_irq (kernel/irq/manage.c:2206) [ 5.126412] pcie_pme_probe (include/linux/interrupt.h:168 drivers/pci/pcie/pme.c:348)
The rest of the stacktrace below is not relevant and could be omitted. The timestamps don't add useful information either.
[ 5.130303] pcie_port_probe_service (drivers/pci/pcie/portdrv.c:528) [ 5.134915] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658) [ 5.138720] __driver_probe_device (drivers/base/dd.c:800) [ 5.143236] driver_probe_device (drivers/base/dd.c:830) [ 5.147571] __device_attach_driver (drivers/base/dd.c:959) [ 5.152179] bus_for_each_drv (drivers/base/bus.c:457) [ 5.156163] __device_attach (drivers/base/dd.c:1032) [ 5.160147] device_initial_probe (drivers/base/dd.c:1080) [ 5.164488] bus_probe_device (drivers/base/bus.c:532) [ 5.168471] device_add (drivers/base/core.c:3638) [ 5.172098] device_register (drivers/base/core.c:3714) [ 5.175994] pcie_portdrv_probe (drivers/pci/pcie/portdrv.c:309 drivers/pci/pcie/portdrv.c:363 drivers/pci/pcie/portdrv.c:695) [ 5.180338] pci_device_probe (drivers/pci/pci-driver.c:324 drivers/pci/pci-driver.c:392 drivers/pci/pci-driver.c:417 drivers/pci/pci-driver.c:460) [ 5.184410] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658) [ 5.188213] __driver_probe_device (drivers/base/dd.c:800) [ 5.192729] driver_probe_device (drivers/base/dd.c:830) [ 5.197064] __device_attach_driver (drivers/base/dd.c:959) [ 5.201672] bus_for_each_drv (drivers/base/bus.c:457) [ 5.205657] __device_attach (drivers/base/dd.c:1032) [ 5.209641] device_attach (drivers/base/dd.c:1074) [ 5.213357] pci_bus_add_device (drivers/pci/bus.c:352) [ 5.217518] pci_bus_add_devices (drivers/pci/bus.c:371 (discriminator 2)) [ 5.221774] pci_host_probe (drivers/pci/probe.c:3099) [ 5.225581] nwl_pcie_probe (drivers/pci/controller/pcie-xilinx-nwl.c:938) [ 5.229562] platform_probe (drivers/base/platform.c:1404) [ 5.233367] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658) [ 5.237169] __driver_probe_device (drivers/base/dd.c:800) [ 5.241685] driver_probe_device (drivers/base/dd.c:830) [ 5.246020] __device_attach_driver (drivers/base/dd.c:959) [ 5.250628] bus_for_each_drv (drivers/base/bus.c:457) [ 5.254612] __device_attach (drivers/base/dd.c:1032) [ 5.258596] device_initial_probe (drivers/base/dd.c:1080) [ 5.262938] bus_probe_device (drivers/base/bus.c:532) [ 5.266920] deferred_probe_work_func (drivers/base/dd.c:124) [ 5.271619] process_one_work (arch/arm64/include/asm/jump_label.h:21 include/linux/jump_label.h:207 include/trace/events/workqueue.h:108 kernel/workqueue.c:2632) [ 5.275788] worker_thread (kernel/workqueue.c:2694 (discriminator 2) kernel/workqueue.c:2781 (discriminator 2)) [ 5.279686] kthread (kernel/kthread.c:388) [ 5.283048] ret_from_fork (arch/arm64/kernel/entry.S:862) [ 5.286765] ================================================================================
Fixes: 9a181e1093af ("PCI: xilinx-nwl: Modify IRQ chip for legacy interrupts") Cc: stable@vger.kernel.org Signed-off-by: Sean Anderson sean.anderson@linux.dev
Changes in v3:
- Expand commit message
drivers/pci/controller/pcie-xilinx-nwl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c index 0408f4d612b5..437927e3bcca 100644 --- a/drivers/pci/controller/pcie-xilinx-nwl.c +++ b/drivers/pci/controller/pcie-xilinx-nwl.c @@ -371,7 +371,7 @@ static void nwl_mask_intx_irq(struct irq_data *data) u32 mask; u32 val;
- mask = 1 << (data->hwirq - 1);
- mask = 1 << data->hwirq; raw_spin_lock_irqsave(&pcie->leg_mask_lock, flags); val = nwl_bridge_readl(pcie, MSGF_LEG_MASK); nwl_bridge_writel(pcie, (val & (~mask)), MSGF_LEG_MASK);
@@ -385,7 +385,7 @@ static void nwl_unmask_intx_irq(struct irq_data *data) u32 mask; u32 val;
- mask = 1 << (data->hwirq - 1);
- mask = 1 << data->hwirq; raw_spin_lock_irqsave(&pcie->leg_mask_lock, flags); val = nwl_bridge_readl(pcie, MSGF_LEG_MASK); nwl_bridge_writel(pcie, (val | mask), MSGF_LEG_MASK);
-- 2.35.1.1320.gc452695387.dirty