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/mouse/lifebook.c | 353 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 353 insertions(+) create mode 100644 drivers/input/mouse/lifebook.c (limited to 'drivers/input/mouse/lifebook.c') diff --git a/drivers/input/mouse/lifebook.c b/drivers/input/mouse/lifebook.c new file mode 100644 index 000000000..ef11b7b19 --- /dev/null +++ b/drivers/input/mouse/lifebook.c @@ -0,0 +1,353 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Fujitsu B-series Lifebook PS/2 TouchScreen driver + * + * Copyright (c) 2005 Vojtech Pavlik + * Copyright (c) 2005 Kenan Esau + * + * TouchScreen detection, absolute mode setting and packet layout is taken from + * Harald Hoyer's description of the device. + */ + +#include +#include +#include +#include +#include +#include + +#include "psmouse.h" +#include "lifebook.h" + +struct lifebook_data { + struct input_dev *dev2; /* Relative device */ + char phys[32]; +}; + +static bool lifebook_present; + +static const char *desired_serio_phys; + +static int lifebook_limit_serio3(const struct dmi_system_id *d) +{ + desired_serio_phys = "isa0060/serio3"; + return 1; +} + +static bool lifebook_use_6byte_proto; + +static int lifebook_set_6byte_proto(const struct dmi_system_id *d) +{ + lifebook_use_6byte_proto = true; + return 1; +} + +static const struct dmi_system_id lifebook_dmi_table[] __initconst = { + { + /* FLORA-ie 55mi */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "FLORA-ie 55mi"), + }, + }, + { + /* LifeBook B */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "Lifebook B Series"), + }, + }, + { + /* LifeBook B */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "LifeBook B Series"), + }, + }, + { + /* Lifebook B */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK B Series"), + }, + }, + { + /* Lifebook B-2130 */ + .matches = { + DMI_MATCH(DMI_BOARD_NAME, "ZEPHYR"), + }, + }, + { + /* Lifebook B213x/B2150 */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "LifeBook B2131/B2133/B2150"), + }, + }, + { + /* Zephyr */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "ZEPHYR"), + }, + }, + { + /* Panasonic CF-18 */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "CF-18"), + }, + .callback = lifebook_limit_serio3, + }, + { + /* Panasonic CF-28 */ + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Matsushita"), + DMI_MATCH(DMI_PRODUCT_NAME, "CF-28"), + }, + .callback = lifebook_set_6byte_proto, + }, + { + /* Panasonic CF-29 */ + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Matsushita"), + DMI_MATCH(DMI_PRODUCT_NAME, "CF-29"), + }, + .callback = lifebook_set_6byte_proto, + }, + { + /* Panasonic CF-72 */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "CF-72"), + }, + .callback = lifebook_set_6byte_proto, + }, + { + /* Lifebook B142 */ + .matches = { + DMI_MATCH(DMI_PRODUCT_NAME, "LifeBook B142"), + }, + }, + { } +}; + +void __init lifebook_module_init(void) +{ + lifebook_present = dmi_check_system(lifebook_dmi_table); +} + +static psmouse_ret_t lifebook_process_byte(struct psmouse *psmouse) +{ + struct lifebook_data *priv = psmouse->private; + struct input_dev *dev1 = psmouse->dev; + struct input_dev *dev2 = priv ? priv->dev2 : NULL; + u8 *packet = psmouse->packet; + bool relative_packet = packet[0] & 0x08; + + if (relative_packet || !lifebook_use_6byte_proto) { + if (psmouse->pktcnt != 3) + return PSMOUSE_GOOD_DATA; + } else { + switch (psmouse->pktcnt) { + case 1: + return (packet[0] & 0xf8) == 0x00 ? + PSMOUSE_GOOD_DATA : PSMOUSE_BAD_DATA; + case 2: + return PSMOUSE_GOOD_DATA; + case 3: + return ((packet[2] & 0x30) << 2) == (packet[2] & 0xc0) ? + PSMOUSE_GOOD_DATA : PSMOUSE_BAD_DATA; + case 4: + return (packet[3] & 0xf8) == 0xc0 ? + PSMOUSE_GOOD_DATA : PSMOUSE_BAD_DATA; + case 5: + return (packet[4] & 0xc0) == (packet[2] & 0xc0) ? + PSMOUSE_GOOD_DATA : PSMOUSE_BAD_DATA; + case 6: + if (((packet[5] & 0x30) << 2) != (packet[5] & 0xc0)) + return PSMOUSE_BAD_DATA; + if ((packet[5] & 0xc0) != (packet[1] & 0xc0)) + return PSMOUSE_BAD_DATA; + break; /* report data */ + } + } + + if (relative_packet) { + if (!dev2) + psmouse_warn(psmouse, + "got relative packet but no relative device set up\n"); + } else { + if (lifebook_use_6byte_proto) { + input_report_abs(dev1, ABS_X, + ((packet[1] & 0x3f) << 6) | (packet[2] & 0x3f)); + input_report_abs(dev1, ABS_Y, + 4096 - (((packet[4] & 0x3f) << 6) | (packet[5] & 0x3f))); + } else { + input_report_abs(dev1, ABS_X, + (packet[1] | ((packet[0] & 0x30) << 4))); + input_report_abs(dev1, ABS_Y, + 1024 - (packet[2] | ((packet[0] & 0xC0) << 2))); + } + input_report_key(dev1, BTN_TOUCH, packet[0] & 0x04); + input_sync(dev1); + } + + if (dev2) { + if (relative_packet) + psmouse_report_standard_motion(dev2, packet); + + psmouse_report_standard_buttons(dev2, packet[0]); + input_sync(dev2); + } + + return PSMOUSE_FULL_PACKET; +} + +static int lifebook_absolute_mode(struct psmouse *psmouse) +{ + struct ps2dev *ps2dev = &psmouse->ps2dev; + u8 param; + int error; + + error = psmouse_reset(psmouse); + if (error) + return error; + + /* + * Enable absolute output -- ps2_command fails always but if + * you leave this call out the touchscreen will never send + * absolute coordinates + */ + param = lifebook_use_6byte_proto ? 0x08 : 0x07; + ps2_command(ps2dev, ¶m, PSMOUSE_CMD_SETRES); + + return 0; +} + +static void lifebook_relative_mode(struct psmouse *psmouse) +{ + struct ps2dev *ps2dev = &psmouse->ps2dev; + u8 param = 0x06; + + ps2_command(ps2dev, ¶m, PSMOUSE_CMD_SETRES); +} + +static void lifebook_set_resolution(struct psmouse *psmouse, unsigned int resolution) +{ + static const u8 params[] = { 0, 1, 2, 2, 3 }; + u8 p; + + if (resolution == 0 || resolution > 400) + resolution = 400; + + p = params[resolution / 100]; + ps2_command(&psmouse->ps2dev, &p, PSMOUSE_CMD_SETRES); + psmouse->resolution = 50 << p; +} + +static void lifebook_disconnect(struct psmouse *psmouse) +{ + struct lifebook_data *priv = psmouse->private; + + psmouse_reset(psmouse); + if (priv) { + input_unregister_device(priv->dev2); + kfree(priv); + } + psmouse->private = NULL; +} + +int lifebook_detect(struct psmouse *psmouse, bool set_properties) +{ + if (!lifebook_present) + return -ENXIO; + + if (desired_serio_phys && + strcmp(psmouse->ps2dev.serio->phys, desired_serio_phys)) + return -ENXIO; + + if (set_properties) { + psmouse->vendor = "Fujitsu"; + psmouse->name = "Lifebook TouchScreen"; + } + + return 0; +} + +static int lifebook_create_relative_device(struct psmouse *psmouse) +{ + struct input_dev *dev2; + struct lifebook_data *priv; + int error = -ENOMEM; + + priv = kzalloc_obj(*priv); + dev2 = input_allocate_device(); + if (!priv || !dev2) + goto err_out; + + priv->dev2 = dev2; + scnprintf(priv->phys, sizeof(priv->phys), + "%s/input1", psmouse->ps2dev.serio->phys); + + dev2->phys = priv->phys; + dev2->name = "LBPS/2 Fujitsu Lifebook Touchpad"; + dev2->id.bustype = BUS_I8042; + dev2->id.vendor = 0x0002; + dev2->id.product = PSMOUSE_LIFEBOOK; + dev2->id.version = 0x0000; + dev2->dev.parent = &psmouse->ps2dev.serio->dev; + + input_set_capability(dev2, EV_REL, REL_X); + input_set_capability(dev2, EV_REL, REL_Y); + input_set_capability(dev2, EV_KEY, BTN_LEFT); + input_set_capability(dev2, EV_KEY, BTN_RIGHT); + + error = input_register_device(priv->dev2); + if (error) + goto err_out; + + psmouse->private = priv; + return 0; + + err_out: + input_free_device(dev2); + kfree(priv); + return error; +} + +int lifebook_init(struct psmouse *psmouse) +{ + struct input_dev *dev1 = psmouse->dev; + int max_coord = lifebook_use_6byte_proto ? 4096 : 1024; + int error; + + error = lifebook_absolute_mode(psmouse); + if (error) + return error; + + /* Clear default capabilities */ + bitmap_zero(dev1->evbit, EV_CNT); + bitmap_zero(dev1->relbit, REL_CNT); + bitmap_zero(dev1->keybit, KEY_CNT); + + input_set_capability(dev1, EV_KEY, BTN_TOUCH); + input_set_abs_params(dev1, ABS_X, 0, max_coord, 0, 0); + input_set_abs_params(dev1, ABS_Y, 0, max_coord, 0, 0); + + if (!desired_serio_phys) { + error = lifebook_create_relative_device(psmouse); + if (error) { + lifebook_relative_mode(psmouse); + return error; + } + } + + psmouse->protocol_handler = lifebook_process_byte; + psmouse->set_resolution = lifebook_set_resolution; + psmouse->disconnect = lifebook_disconnect; + psmouse->reconnect = lifebook_absolute_mode; + + psmouse->model = lifebook_use_6byte_proto ? 6 : 3; + + /* + * Use packet size = 3 even when using 6-byte protocol because + * that's what POLL will return on Lifebooks (according to spec). + */ + psmouse->pktsize = 3; + + return 0; +} + -- cgit v1.3.1