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, 204 insertions, 0 deletions

diff --git a/drivers/hid/hid-pl.c b/drivers/hid/hid-pl.c
new file mode 100644
index 000000000..cae56a6c9
--- /dev/null
+++ b/drivers/hid/hid-pl.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Force feedback support for PantherLord/GreenAsia based devices
+ *
+ *  The devices are distributed under various names and the same USB device ID
+ *  can be used in both adapters and actual game controllers.
+ *
+ *  0810:0001 "Twin USB Joystick"
+ *   - tested with PantherLord USB/PS2 2in1 Adapter
+ *   - contains two reports, one for each port (HID_QUIRK_MULTI_INPUT)
+ *
+ *  0e8f:0003 "GreenAsia Inc.    USB Joystick     "
+ *   - tested with König Gaming gamepad
+ *
+ *  0e8f:0003 "GASIA USB Gamepad"
+ *   - another version of the König gamepad
+ *
+ *  0f30:0111 "Saitek Color Rumble Pad"
+ *
+ *  Copyright (c) 2007, 2009 Anssi Hannula <anssi.hannula@gmail.com>
+ */
+
+/*
+ */
+
+
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/hid.h>
+
+#include "hid-ids.h"
+
+#ifdef CONFIG_PANTHERLORD_FF
+
+struct plff_device {
+	struct hid_report *report;
+	s32 maxval;
+	s32 *strong;
+	s32 *weak;
+};
+
+static int hid_plff_play(struct input_dev *dev, void *data,
+			 struct ff_effect *effect)
+{
+	struct hid_device *hid = input_get_drvdata(dev);
+	struct plff_device *plff = data;
+	int left, right;
+
+	left = effect->u.rumble.strong_magnitude;
+	right = effect->u.rumble.weak_magnitude;
+	hid_dbg(dev, "called with 0x%04x 0x%04x", left, right);
+
+	left = left * plff->maxval / 0xffff;
+	right = right * plff->maxval / 0xffff;
+
+	*plff->strong = left;
+	*plff->weak = right;
+	hid_dbg(dev, "running with 0x%02x 0x%02x", left, right);
+	hid_hw_request(hid, plff->report, HID_REQ_SET_REPORT);
+
+	return 0;
+}
+
+static int pl_input_configured(struct hid_device *hid, struct hid_input *hidinput)
+{
+	struct plff_device *plff;
+	struct hid_report *report;
+	struct list_head *report_list =
+			&hid->report_enum[HID_OUTPUT_REPORT].report_list;
+	struct input_dev *dev = hidinput->input;
+	int error;
+	s32 maxval;
+	s32 *strong;
+	s32 *weak;
+
+	/* The device contains one output report per physical device, all
+	   containing 1 field, which contains 4 ff00.0002 usages and 4 16bit
+	   absolute values.
+
+	   The input reports also contain a field which contains
+	   8 ff00.0001 usages and 8 boolean values. Their meaning is
+	   currently unknown.
+
+	   A version of the 0e8f:0003 exists that has all the values in
+	   separate fields and misses the extra input field, thus resembling
+	   Zeroplus (hid-zpff) devices.
+	*/
+
+	if (!list_is_first(&hidinput->list, &hid->inputs))
+		return 0;
+
+	report = list_first_entry_or_null(report_list, struct hid_report, list);
+	if (!report) {
+		hid_err(hid, "no output reports found\n");
+		return -ENODEV;
+	}
+	if (report->maxfield < 1) {
+		hid_err(hid, "no fields in the report\n");
+		return -ENODEV;
+	}
+
+	maxval = 0x7f;
+	if (report->field[0]->report_count >= 4) {
+		report->field[0]->value[0] = 0x00;
+		report->field[0]->value[1] = 0x00;
+		strong = &report->field[0]->value[2];
+		weak = &report->field[0]->value[3];
+		hid_dbg(hid, "detected single-field device");
+	} else if (report->field[0]->maxusage == 1 &&
+		   report->field[0]->usage[0].hid ==
+			(HID_UP_LED | 0x43) &&
+		   report->maxfield >= 4 &&
+		   report->field[0]->report_count >= 1 &&
+		   report->field[1]->report_count >= 1 &&
+		   report->field[2]->report_count >= 1 &&
+		   report->field[3]->report_count >= 1) {
+		report->field[0]->value[0] = 0x00;
+		report->field[1]->value[0] = 0x00;
+		strong = &report->field[2]->value[0];
+		weak = &report->field[3]->value[0];
+		if (hid->vendor == USB_VENDOR_ID_JESS2)
+			maxval = 0xff;
+		hid_dbg(hid, "detected 4-field device");
+	} else {
+		hid_err(hid, "not enough fields or values\n");
+		return -ENODEV;
+	}
+
+	plff = kzalloc_obj(struct plff_device);
+	if (!plff)
+		return -ENOMEM;
+
+	dev = hidinput->input;
+
+	set_bit(FF_RUMBLE, dev->ffbit);
+
+	error = input_ff_create_memless(dev, plff, hid_plff_play);
+	if (error) {
+		kfree(plff);
+		return error;
+	}
+
+	plff->report = report;
+	plff->strong = strong;
+	plff->weak = weak;
+	plff->maxval = maxval;
+
+	*strong = 0x00;
+	*weak = 0x00;
+	hid_hw_request(hid, plff->report, HID_REQ_SET_REPORT);
+
+	return 0;
+}
+#else
+static inline int pl_input_configured(struct hid_device *hid,
+				      struct hid_input *hidinput)
+{
+	return 0;
+}
+#endif
+
+static int pl_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+
+	if (id->driver_data)
+		hdev->quirks |= HID_QUIRK_MULTI_INPUT;
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		return ret;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+static const struct hid_device_id pl_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GAMERON, USB_DEVICE_ID_GAMERON_DUAL_PSX_ADAPTOR),
+		.driver_data = 1 }, /* Twin USB Joystick */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GAMERON, USB_DEVICE_ID_GAMERON_DUAL_PCS_ADAPTOR),
+		.driver_data = 1 }, /* Twin USB Joystick */
+	{ HID_USB_DEVICE(USB_VENDOR_ID_GREENASIA, 0x0003), },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_JESS2, USB_DEVICE_ID_JESS2_COLOR_RUMBLE_PAD), },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, pl_devices);
+
+static struct hid_driver pl_driver = {
+	.name = "pantherlord",
+	.id_table = pl_devices,
+	.probe = pl_probe,
+	.input_configured = pl_input_configured,
+};
+module_hid_driver(pl_driver);
+
+MODULE_DESCRIPTION("Force feedback support for PantherLord/GreenAsia based devices");
+MODULE_LICENSE("GPL");