x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 254 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-ps3.c b/drivers/usb/host/ehci-ps3.c
new file mode 100644
index 000000000..98568b046
--- /dev/null
+++ b/drivers/usb/host/ehci-ps3.c
@@ -0,0 +1,254 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  PS3 EHCI Host Controller driver
+ *
+ *  Copyright (C) 2006 Sony Computer Entertainment Inc.
+ *  Copyright 2006 Sony Corp.
+ */
+
+#include <asm/firmware.h>
+#include <asm/ps3.h>
+
+static void ps3_ehci_setup_insnreg(struct ehci_hcd *ehci)
+{
+	/* PS3 HC internal setup register offsets. */
+
+	enum ps3_ehci_hc_insnreg {
+		ps3_ehci_hc_insnreg01 = 0x084,
+		ps3_ehci_hc_insnreg02 = 0x088,
+		ps3_ehci_hc_insnreg03 = 0x08c,
+	};
+
+	/* PS3 EHCI HC errata fix 316 - The PS3 EHCI HC will reset its
+	 * internal INSNREGXX setup regs back to the chip default values
+	 * on Host Controller Reset (CMD_RESET) or Light Host Controller
+	 * Reset (CMD_LRESET).  The work-around for this is for the HC
+	 * driver to re-initialise these regs when ever the HC is reset.
+	 */
+
+	/* Set burst transfer counts to 256 out, 32 in. */
+
+	writel_be(0x01000020, (void __iomem *)ehci->regs +
+		ps3_ehci_hc_insnreg01);
+
+	/* Enable burst transfer counts. */
+
+	writel_be(0x00000001, (void __iomem *)ehci->regs +
+		ps3_ehci_hc_insnreg03);
+}
+
+static int ps3_ehci_hc_reset(struct usb_hcd *hcd)
+{
+	int result;
+	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+
+	ehci->big_endian_mmio = 1;
+	ehci->caps = hcd->regs;
+
+	result = ehci_setup(hcd);
+	if (result)
+		return result;
+
+	ps3_ehci_setup_insnreg(ehci);
+
+	return result;
+}
+
+static const struct hc_driver ps3_ehci_hc_driver = {
+	.description		= hcd_name,
+	.product_desc		= "PS3 EHCI Host Controller",
+	.hcd_priv_size		= sizeof(struct ehci_hcd),
+	.irq			= ehci_irq,
+	.flags			= HCD_MEMORY | HCD_DMA | HCD_USB2 | HCD_BH,
+	.reset			= ps3_ehci_hc_reset,
+	.start			= ehci_run,
+	.stop			= ehci_stop,
+	.shutdown		= ehci_shutdown,
+	.urb_enqueue		= ehci_urb_enqueue,
+	.urb_dequeue		= ehci_urb_dequeue,
+	.endpoint_disable	= ehci_endpoint_disable,
+	.endpoint_reset		= ehci_endpoint_reset,
+	.get_frame_number	= ehci_get_frame,
+	.hub_status_data	= ehci_hub_status_data,
+	.hub_control		= ehci_hub_control,
+#if defined(CONFIG_PM)
+	.bus_suspend		= ehci_bus_suspend,
+	.bus_resume		= ehci_bus_resume,
+#endif
+	.relinquish_port	= ehci_relinquish_port,
+	.port_handed_over	= ehci_port_handed_over,
+
+	.clear_tt_buffer_complete	= ehci_clear_tt_buffer_complete,
+};
+
+static int ps3_ehci_probe(struct ps3_system_bus_device *dev)
+{
+	int result;
+	struct usb_hcd *hcd;
+	unsigned int virq;
+	static u64 dummy_mask;
+
+	if (usb_disabled()) {
+		result = -ENODEV;
+		goto fail_start;
+	}
+
+	result = ps3_open_hv_device(dev);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: ps3_open_hv_device failed\n",
+			__func__, __LINE__);
+		goto fail_open;
+	}
+
+	result = ps3_dma_region_create(dev->d_region);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: ps3_dma_region_create failed: "
+			"(%d)\n", __func__, __LINE__, result);
+		BUG_ON("check region type");
+		goto fail_dma_region;
+	}
+
+	result = ps3_mmio_region_create(dev->m_region);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: ps3_map_mmio_region failed\n",
+			__func__, __LINE__);
+		result = -EPERM;
+		goto fail_mmio_region;
+	}
+
+	dev_dbg(&dev->core, "%s:%d: mmio mapped_addr %lxh\n", __func__,
+		__LINE__, dev->m_region->lpar_addr);
+
+	result = ps3_io_irq_setup(PS3_BINDING_CPU_ANY, dev->interrupt_id, &virq);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: ps3_construct_io_irq(%d) failed.\n",
+			__func__, __LINE__, virq);
+		result = -EPERM;
+		goto fail_irq;
+	}
+
+	dummy_mask = DMA_BIT_MASK(32);
+	dev->core.dma_mask = &dummy_mask;
+	dma_set_coherent_mask(&dev->core, dummy_mask);
+
+	hcd = usb_create_hcd(&ps3_ehci_hc_driver, &dev->core, dev_name(&dev->core));
+
+	if (!hcd) {
+		dev_dbg(&dev->core, "%s:%d: usb_create_hcd failed\n", __func__,
+			__LINE__);
+		result = -ENOMEM;
+		goto fail_create_hcd;
+	}
+
+	hcd->rsrc_start = dev->m_region->lpar_addr;
+	hcd->rsrc_len = dev->m_region->len;
+
+	if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len, hcd_name))
+		dev_dbg(&dev->core, "%s:%d: request_mem_region failed\n",
+			__func__, __LINE__);
+
+	hcd->regs = ioremap(dev->m_region->lpar_addr, dev->m_region->len);
+
+	if (!hcd->regs) {
+		dev_dbg(&dev->core, "%s:%d: ioremap failed\n", __func__,
+			__LINE__);
+		result = -EPERM;
+		goto fail_ioremap;
+	}
+
+	dev_dbg(&dev->core, "%s:%d: hcd->rsrc_start %lxh\n", __func__, __LINE__,
+		(unsigned long)hcd->rsrc_start);
+	dev_dbg(&dev->core, "%s:%d: hcd->rsrc_len   %lxh\n", __func__, __LINE__,
+		(unsigned long)hcd->rsrc_len);
+	dev_dbg(&dev->core, "%s:%d: hcd->regs       %lxh\n", __func__, __LINE__,
+		(unsigned long)hcd->regs);
+	dev_dbg(&dev->core, "%s:%d: virq            %lu\n", __func__, __LINE__,
+		(unsigned long)virq);
+
+	ps3_system_bus_set_drvdata(dev, hcd);
+
+	result = usb_add_hcd(hcd, virq, 0);
+
+	if (result) {
+		dev_dbg(&dev->core, "%s:%d: usb_add_hcd failed (%d)\n",
+			__func__, __LINE__, result);
+		goto fail_add_hcd;
+	}
+
+	device_wakeup_enable(hcd->self.controller);
+	return result;
+
+fail_add_hcd:
+	iounmap(hcd->regs);
+fail_ioremap:
+	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
+	usb_put_hcd(hcd);
+fail_create_hcd:
+	ps3_io_irq_destroy(virq);
+fail_irq:
+	ps3_free_mmio_region(dev->m_region);
+fail_mmio_region:
+	ps3_dma_region_free(dev->d_region);
+fail_dma_region:
+	ps3_close_hv_device(dev);
+fail_open:
+fail_start:
+	return result;
+}
+
+static void ps3_ehci_remove(struct ps3_system_bus_device *dev)
+{
+	unsigned int tmp;
+	struct usb_hcd *hcd = ps3_system_bus_get_drvdata(dev);
+
+	BUG_ON(!hcd);
+
+	dev_dbg(&dev->core, "%s:%d: regs %p\n", __func__, __LINE__, hcd->regs);
+	dev_dbg(&dev->core, "%s:%d: irq %u\n", __func__, __LINE__, hcd->irq);
+
+	tmp = hcd->irq;
+
+	usb_remove_hcd(hcd);
+
+	ps3_system_bus_set_drvdata(dev, NULL);
+
+	BUG_ON(!hcd->regs);
+	iounmap(hcd->regs);
+
+	release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
+	usb_put_hcd(hcd);
+
+	ps3_io_irq_destroy(tmp);
+	ps3_free_mmio_region(dev->m_region);
+
+	ps3_dma_region_free(dev->d_region);
+	ps3_close_hv_device(dev);
+}
+
+static int __init ps3_ehci_driver_register(struct ps3_system_bus_driver *drv)
+{
+	return firmware_has_feature(FW_FEATURE_PS3_LV1)
+		? ps3_system_bus_driver_register(drv)
+		: 0;
+}
+
+static void ps3_ehci_driver_unregister(struct ps3_system_bus_driver *drv)
+{
+	if (firmware_has_feature(FW_FEATURE_PS3_LV1))
+		ps3_system_bus_driver_unregister(drv);
+}
+
+MODULE_ALIAS(PS3_MODULE_ALIAS_EHCI);
+
+static struct ps3_system_bus_driver ps3_ehci_driver = {
+	.core.name = "ps3-ehci-driver",
+	.core.owner = THIS_MODULE,
+	.match_id = PS3_MATCH_ID_EHCI,
+	.probe = ps3_ehci_probe,
+	.remove = ps3_ehci_remove,
+	.shutdown = ps3_ehci_remove,
+};