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, 274 insertions, 0 deletions

diff --git a/drivers/usb/host/ssb-hcd.c b/drivers/usb/host/ssb-hcd.c
new file mode 100644
index 000000000..016987764
--- /dev/null
+++ b/drivers/usb/host/ssb-hcd.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sonics Silicon Backplane
+ * Broadcom USB-core driver  (SSB bus glue)
+ *
+ * Copyright 2011-2012 Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * Based on ssb-ohci driver
+ * Copyright 2007 Michael Buesch <m@bues.ch>
+ *
+ * Derived from the OHCI-PCI driver
+ * Copyright 1999 Roman Weissgaerber
+ * Copyright 2000-2002 David Brownell
+ * Copyright 1999 Linus Torvalds
+ * Copyright 1999 Gregory P. Smith
+ *
+ * Derived from the USBcore related parts of Broadcom-SB
+ * Copyright 2005-2011 Broadcom Corporation
+ */
+#include <linux/ssb/ssb.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb/ehci_pdriver.h>
+#include <linux/usb/ohci_pdriver.h>
+
+MODULE_AUTHOR("Hauke Mehrtens");
+MODULE_DESCRIPTION("Common USB driver for SSB Bus");
+MODULE_LICENSE("GPL");
+
+#define SSB_HCD_TMSLOW_HOSTMODE	(1 << 29)
+
+struct ssb_hcd_device {
+	struct platform_device *ehci_dev;
+	struct platform_device *ohci_dev;
+
+	u32 enable_flags;
+};
+
+static void ssb_hcd_5354wa(struct ssb_device *dev)
+{
+#ifdef CONFIG_SSB_DRIVER_MIPS
+	/* Work around for 5354 failures */
+	if (dev->id.revision == 2 && dev->bus->chip_id == 0x5354) {
+		/* Change syn01 reg */
+		ssb_write32(dev, 0x894, 0x00fe00fe);
+
+		/* Change syn03 reg */
+		ssb_write32(dev, 0x89c, ssb_read32(dev, 0x89c) | 0x1);
+	}
+#endif
+}
+
+static void ssb_hcd_usb20wa(struct ssb_device *dev)
+{
+	if (dev->id.coreid == SSB_DEV_USB20_HOST) {
+		/*
+		 * USB 2.0 special considerations:
+		 *
+		 * In addition to the standard SSB reset sequence, the Host
+		 * Control Register must be programmed to bring the USB core
+		 * and various phy components out of reset.
+		 */
+		ssb_write32(dev, 0x200, 0x7ff);
+
+		/* Change Flush control reg */
+		ssb_write32(dev, 0x400, ssb_read32(dev, 0x400) & ~8);
+		ssb_read32(dev, 0x400);
+
+		/* Change Shim control reg */
+		ssb_write32(dev, 0x304, ssb_read32(dev, 0x304) & ~0x100);
+		ssb_read32(dev, 0x304);
+
+		udelay(1);
+
+		ssb_hcd_5354wa(dev);
+	}
+}
+
+/* based on arch/mips/brcm-boards/bcm947xx/pcibios.c */
+static u32 ssb_hcd_init_chip(struct ssb_device *dev)
+{
+	u32 flags = 0;
+
+	if (dev->id.coreid == SSB_DEV_USB11_HOSTDEV)
+		/* Put the device into host-mode. */
+		flags |= SSB_HCD_TMSLOW_HOSTMODE;
+
+	ssb_device_enable(dev, flags);
+
+	ssb_hcd_usb20wa(dev);
+
+	return flags;
+}
+
+static const struct usb_ehci_pdata ehci_pdata = {
+};
+
+static const struct usb_ohci_pdata ohci_pdata = {
+};
+
+static struct platform_device *ssb_hcd_create_pdev(struct ssb_device *dev, bool ohci, u32 addr, u32 len)
+{
+	struct platform_device *hci_dev;
+	struct resource hci_res[2];
+	int ret;
+
+	memset(hci_res, 0, sizeof(hci_res));
+
+	hci_res[0].start = addr;
+	hci_res[0].end = hci_res[0].start + len - 1;
+	hci_res[0].flags = IORESOURCE_MEM;
+
+	hci_res[1].start = dev->irq;
+	hci_res[1].flags = IORESOURCE_IRQ;
+
+	hci_dev = platform_device_alloc(ohci ? "ohci-platform" :
+					"ehci-platform" , 0);
+	if (!hci_dev)
+		return ERR_PTR(-ENOMEM);
+
+	hci_dev->dev.parent = dev->dev;
+	hci_dev->dev.dma_mask = &hci_dev->dev.coherent_dma_mask;
+
+	ret = platform_device_add_resources(hci_dev, hci_res,
+					    ARRAY_SIZE(hci_res));
+	if (ret)
+		goto err_alloc;
+	if (ohci)
+		ret = platform_device_add_data(hci_dev, &ohci_pdata,
+					       sizeof(ohci_pdata));
+	else
+		ret = platform_device_add_data(hci_dev, &ehci_pdata,
+					       sizeof(ehci_pdata));
+	if (ret)
+		goto err_alloc;
+	ret = platform_device_add(hci_dev);
+	if (ret)
+		goto err_alloc;
+
+	return hci_dev;
+
+err_alloc:
+	platform_device_put(hci_dev);
+	return ERR_PTR(ret);
+}
+
+static int ssb_hcd_probe(struct ssb_device *dev,
+				   const struct ssb_device_id *id)
+{
+	int err, tmp;
+	int start, len;
+	u16 chipid_top;
+	u16 coreid = dev->id.coreid;
+	struct ssb_hcd_device *usb_dev;
+
+	/* USBcores are only connected on embedded devices. */
+	chipid_top = (dev->bus->chip_id & 0xFF00);
+	if (chipid_top != 0x4700 && chipid_top != 0x5300)
+		return -ENODEV;
+
+	/* TODO: Probably need checks here; is the core connected? */
+
+	if (dma_set_mask_and_coherent(dev->dma_dev, DMA_BIT_MASK(32)))
+		return -EOPNOTSUPP;
+
+	usb_dev = devm_kzalloc(dev->dev, sizeof(struct ssb_hcd_device),
+			       GFP_KERNEL);
+	if (!usb_dev)
+		return -ENOMEM;
+
+	/* We currently always attach SSB_DEV_USB11_HOSTDEV
+	 * as HOST OHCI. If we want to attach it as Client device,
+	 * we must branch here and call into the (yet to
+	 * be written) Client mode driver. Same for remove(). */
+	usb_dev->enable_flags = ssb_hcd_init_chip(dev);
+
+	tmp = ssb_read32(dev, SSB_ADMATCH0);
+
+	start = ssb_admatch_base(tmp);
+	len = (coreid == SSB_DEV_USB20_HOST) ? 0x800 : ssb_admatch_size(tmp);
+	usb_dev->ohci_dev = ssb_hcd_create_pdev(dev, true, start, len);
+	if (IS_ERR(usb_dev->ohci_dev))
+		return PTR_ERR(usb_dev->ohci_dev);
+
+	if (coreid == SSB_DEV_USB20_HOST) {
+		start = ssb_admatch_base(tmp) + 0x800; /* ehci core offset */
+		usb_dev->ehci_dev = ssb_hcd_create_pdev(dev, false, start, len);
+		if (IS_ERR(usb_dev->ehci_dev)) {
+			err = PTR_ERR(usb_dev->ehci_dev);
+			goto err_unregister_ohci_dev;
+		}
+	}
+
+	ssb_set_drvdata(dev, usb_dev);
+	return 0;
+
+err_unregister_ohci_dev:
+	platform_device_unregister(usb_dev->ohci_dev);
+	return err;
+}
+
+static void ssb_hcd_remove(struct ssb_device *dev)
+{
+	struct ssb_hcd_device *usb_dev = ssb_get_drvdata(dev);
+	struct platform_device *ohci_dev = usb_dev->ohci_dev;
+	struct platform_device *ehci_dev = usb_dev->ehci_dev;
+
+	if (ohci_dev)
+		platform_device_unregister(ohci_dev);
+	if (ehci_dev)
+		platform_device_unregister(ehci_dev);
+
+	ssb_device_disable(dev, 0);
+}
+
+static void ssb_hcd_shutdown(struct ssb_device *dev)
+{
+	ssb_device_disable(dev, 0);
+}
+
+#ifdef CONFIG_PM
+
+static int ssb_hcd_suspend(struct ssb_device *dev, pm_message_t state)
+{
+	ssb_device_disable(dev, 0);
+
+	return 0;
+}
+
+static int ssb_hcd_resume(struct ssb_device *dev)
+{
+	struct ssb_hcd_device *usb_dev = ssb_get_drvdata(dev);
+
+	ssb_device_enable(dev, usb_dev->enable_flags);
+
+	return 0;
+}
+
+#else /* !CONFIG_PM */
+#define ssb_hcd_suspend	NULL
+#define ssb_hcd_resume	NULL
+#endif /* CONFIG_PM */
+
+static const struct ssb_device_id ssb_hcd_table[] = {
+	SSB_DEVICE(SSB_VENDOR_BROADCOM, SSB_DEV_USB11_HOSTDEV, SSB_ANY_REV),
+	SSB_DEVICE(SSB_VENDOR_BROADCOM, SSB_DEV_USB11_HOST, SSB_ANY_REV),
+	SSB_DEVICE(SSB_VENDOR_BROADCOM, SSB_DEV_USB20_HOST, SSB_ANY_REV),
+	{},
+};
+MODULE_DEVICE_TABLE(ssb, ssb_hcd_table);
+
+static struct ssb_driver ssb_hcd_driver = {
+	.name		= KBUILD_MODNAME,
+	.id_table	= ssb_hcd_table,
+	.probe		= ssb_hcd_probe,
+	.remove		= ssb_hcd_remove,
+	.shutdown	= ssb_hcd_shutdown,
+	.suspend	= ssb_hcd_suspend,
+	.resume		= ssb_hcd_resume,
+};
+
+static int __init ssb_hcd_init(void)
+{
+	return ssb_driver_register(&ssb_hcd_driver);
+}
+module_init(ssb_hcd_init);
+
+static void __exit ssb_hcd_exit(void)
+{
+	ssb_driver_unregister(&ssb_hcd_driver);
+}
+module_exit(ssb_hcd_exit);