From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions 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) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/input/joystick/interact.c | 294 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 294 insertions(+) create mode 100644 drivers/input/joystick/interact.c (limited to 'drivers/input/joystick/interact.c') diff --git a/drivers/input/joystick/interact.c b/drivers/input/joystick/interact.c new file mode 100644 index 000000000..507cec36b --- /dev/null +++ b/drivers/input/joystick/interact.c @@ -0,0 +1,294 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2001 Vojtech Pavlik + * + * Based on the work of: + * Toby Deshane + */ + +/* + * InterAct digital gamepad/joystick driver for Linux + */ + +#include +#include +#include +#include +#include +#include +#include + +#define DRIVER_DESC "InterAct digital joystick driver" + +MODULE_AUTHOR("Vojtech Pavlik "); +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_LICENSE("GPL"); + +#define INTERACT_MAX_START 600 /* 400 us */ +#define INTERACT_MAX_STROBE 60 /* 40 us */ +#define INTERACT_MAX_LENGTH 32 /* 32 bits */ + +#define INTERACT_TYPE_HHFX 0 /* HammerHead/FX */ +#define INTERACT_TYPE_PP8D 1 /* ProPad 8 */ + +struct interact { + struct gameport *gameport; + struct input_dev *dev; + int bads; + int reads; + unsigned char type; + unsigned char length; + char phys[32]; +}; + +static short interact_abs_hhfx[] = + { ABS_RX, ABS_RY, ABS_X, ABS_Y, ABS_HAT0X, ABS_HAT0Y, -1 }; +static short interact_abs_pp8d[] = + { ABS_X, ABS_Y, -1 }; + +static short interact_btn_hhfx[] = + { BTN_TR, BTN_X, BTN_Y, BTN_Z, BTN_A, BTN_B, BTN_C, BTN_TL, BTN_TL2, BTN_TR2, BTN_MODE, BTN_SELECT, -1 }; +static short interact_btn_pp8d[] = + { BTN_C, BTN_TL, BTN_TR, BTN_A, BTN_B, BTN_Y, BTN_Z, BTN_X, -1 }; + +struct interact_type { + int id; + short *abs; + short *btn; + char *name; + unsigned char length; + unsigned char b8; +}; + +static struct interact_type interact_type[] = { + { 0x6202, interact_abs_hhfx, interact_btn_hhfx, "InterAct HammerHead/FX", 32, 4 }, + { 0x53f8, interact_abs_pp8d, interact_btn_pp8d, "InterAct ProPad 8 Digital", 16, 0 }, + { 0 }}; + +/* + * interact_read_packet() reads and InterAct joystick data. + */ + +static int interact_read_packet(struct gameport *gameport, int length, u32 *data) +{ + unsigned long flags; + unsigned char u, v; + unsigned int t, s; + int i; + + i = 0; + data[0] = data[1] = data[2] = 0; + t = gameport_time(gameport, INTERACT_MAX_START); + s = gameport_time(gameport, INTERACT_MAX_STROBE); + + local_irq_save(flags); + gameport_trigger(gameport); + v = gameport_read(gameport); + + while (t > 0 && i < length) { + t--; + u = v; v = gameport_read(gameport); + if (v & ~u & 0x40) { + data[0] = (data[0] << 1) | ((v >> 4) & 1); + data[1] = (data[1] << 1) | ((v >> 5) & 1); + data[2] = (data[2] << 1) | ((v >> 7) & 1); + i++; + t = s; + } + } + + local_irq_restore(flags); + + return i; +} + +/* + * interact_poll() reads and analyzes InterAct joystick data. + */ + +static void interact_poll(struct gameport *gameport) +{ + struct interact *interact = gameport_get_drvdata(gameport); + struct input_dev *dev = interact->dev; + u32 data[3]; + int i; + + interact->reads++; + + if (interact_read_packet(interact->gameport, interact->length, data) < interact->length) { + interact->bads++; + } else { + + for (i = 0; i < 3; i++) + data[i] <<= INTERACT_MAX_LENGTH - interact->length; + + switch (interact->type) { + + case INTERACT_TYPE_HHFX: + + for (i = 0; i < 4; i++) + input_report_abs(dev, interact_abs_hhfx[i], (data[i & 1] >> ((i >> 1) << 3)) & 0xff); + + for (i = 0; i < 2; i++) + input_report_abs(dev, ABS_HAT0Y - i, + ((data[1] >> ((i << 1) + 17)) & 1) - ((data[1] >> ((i << 1) + 16)) & 1)); + + for (i = 0; i < 8; i++) + input_report_key(dev, interact_btn_hhfx[i], (data[0] >> (i + 16)) & 1); + + for (i = 0; i < 4; i++) + input_report_key(dev, interact_btn_hhfx[i + 8], (data[1] >> (i + 20)) & 1); + + break; + + case INTERACT_TYPE_PP8D: + + for (i = 0; i < 2; i++) + input_report_abs(dev, interact_abs_pp8d[i], + ((data[0] >> ((i << 1) + 20)) & 1) - ((data[0] >> ((i << 1) + 21)) & 1)); + + for (i = 0; i < 8; i++) + input_report_key(dev, interact_btn_pp8d[i], (data[1] >> (i + 16)) & 1); + + break; + } + } + + input_sync(dev); +} + +/* + * interact_open() is a callback from the input open routine. + */ + +static int interact_open(struct input_dev *dev) +{ + struct interact *interact = input_get_drvdata(dev); + + gameport_start_polling(interact->gameport); + return 0; +} + +/* + * interact_close() is a callback from the input close routine. + */ + +static void interact_close(struct input_dev *dev) +{ + struct interact *interact = input_get_drvdata(dev); + + gameport_stop_polling(interact->gameport); +} + +/* + * interact_connect() probes for InterAct joysticks. + */ + +static int interact_connect(struct gameport *gameport, struct gameport_driver *drv) +{ + struct interact *interact; + struct input_dev *input_dev; + __u32 data[3]; + int i, t; + int err; + + interact = kzalloc_obj(*interact); + input_dev = input_allocate_device(); + if (!interact || !input_dev) { + err = -ENOMEM; + goto fail1; + } + + interact->gameport = gameport; + interact->dev = input_dev; + + gameport_set_drvdata(gameport, interact); + + err = gameport_open(gameport, drv, GAMEPORT_MODE_RAW); + if (err) + goto fail1; + + i = interact_read_packet(gameport, INTERACT_MAX_LENGTH * 2, data); + + if (i != 32 || (data[0] >> 24) != 0x0c || (data[1] >> 24) != 0x02) { + err = -ENODEV; + goto fail2; + } + + for (i = 0; interact_type[i].length; i++) + if (interact_type[i].id == (data[2] >> 16)) + break; + + if (!interact_type[i].length) { + printk(KERN_WARNING "interact.c: Unknown joystick on %s. [len %d d0 %08x d1 %08x i2 %08x]\n", + gameport->phys, i, data[0], data[1], data[2]); + err = -ENODEV; + goto fail2; + } + + gameport_set_poll_handler(gameport, interact_poll); + gameport_set_poll_interval(gameport, 20); + + snprintf(interact->phys, sizeof(interact->phys), "%s/input0", gameport->phys); + + interact->type = i; + interact->length = interact_type[i].length; + + input_dev->name = interact_type[i].name; + input_dev->phys = interact->phys; + input_dev->id.bustype = BUS_GAMEPORT; + input_dev->id.vendor = GAMEPORT_ID_VENDOR_INTERACT; + input_dev->id.product = interact_type[i].id; + input_dev->id.version = 0x0100; + input_dev->dev.parent = &gameport->dev; + + input_set_drvdata(input_dev, interact); + + input_dev->open = interact_open; + input_dev->close = interact_close; + + input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); + + for (i = 0; (t = interact_type[interact->type].abs[i]) >= 0; i++) { + if (i < interact_type[interact->type].b8) + input_set_abs_params(input_dev, t, 0, 255, 0, 0); + else + input_set_abs_params(input_dev, t, -1, 1, 0, 0); + } + + for (i = 0; (t = interact_type[interact->type].btn[i]) >= 0; i++) + __set_bit(t, input_dev->keybit); + + err = input_register_device(interact->dev); + if (err) + goto fail2; + + return 0; + +fail2: gameport_close(gameport); +fail1: gameport_set_drvdata(gameport, NULL); + input_free_device(input_dev); + kfree(interact); + return err; +} + +static void interact_disconnect(struct gameport *gameport) +{ + struct interact *interact = gameport_get_drvdata(gameport); + + input_unregister_device(interact->dev); + gameport_close(gameport); + gameport_set_drvdata(gameport, NULL); + kfree(interact); +} + +static struct gameport_driver interact_drv = { + .driver = { + .name = "interact", + }, + .description = DRIVER_DESC, + .connect = interact_connect, + .disconnect = interact_disconnect, +}; + +module_gameport_driver(interact_drv); -- cgit v1.3.1