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/touchscreen/tsc2007.h | 102 ++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 drivers/input/touchscreen/tsc2007.h (limited to 'drivers/input/touchscreen/tsc2007.h') diff --git a/drivers/input/touchscreen/tsc2007.h b/drivers/input/touchscreen/tsc2007.h new file mode 100644 index 000000000..e346fb4f7 --- /dev/null +++ b/drivers/input/touchscreen/tsc2007.h @@ -0,0 +1,102 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +/* + * Copyright (c) 2008 MtekVision Co., Ltd. + * Kwangwoo Lee + * + * Using code from: + * - ads7846.c + * Copyright (c) 2005 David Brownell + * Copyright (c) 2006 Nokia Corporation + * - corgi_ts.c + * Copyright (C) 2004-2005 Richard Purdie + * - omap_ts.[hc], ads7846.h, ts_osk.c + * Copyright (C) 2002 MontaVista Software + * Copyright (C) 2004 Texas Instruments + * Copyright (C) 2005 Dirk Behme + */ + +#ifndef _TSC2007_H +#define _TSC2007_H + +#include +struct gpio_desc; + +#define TSC2007_MEASURE_TEMP0 (0x0 << 4) +#define TSC2007_MEASURE_AUX (0x2 << 4) +#define TSC2007_MEASURE_TEMP1 (0x4 << 4) +#define TSC2007_ACTIVATE_XN (0x8 << 4) +#define TSC2007_ACTIVATE_YN (0x9 << 4) +#define TSC2007_ACTIVATE_YP_XN (0xa << 4) +#define TSC2007_SETUP (0xb << 4) +#define TSC2007_MEASURE_X (0xc << 4) +#define TSC2007_MEASURE_Y (0xd << 4) +#define TSC2007_MEASURE_Z1 (0xe << 4) +#define TSC2007_MEASURE_Z2 (0xf << 4) + +#define TSC2007_POWER_OFF_IRQ_EN (0x0 << 2) +#define TSC2007_ADC_ON_IRQ_DIS0 (0x1 << 2) +#define TSC2007_ADC_OFF_IRQ_EN (0x2 << 2) +#define TSC2007_ADC_ON_IRQ_DIS1 (0x3 << 2) + +#define TSC2007_12BIT (0x0 << 1) +#define TSC2007_8BIT (0x1 << 1) + +#define MAX_12BIT ((1 << 12) - 1) + +#define ADC_ON_12BIT (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0) + +#define READ_Y (ADC_ON_12BIT | TSC2007_MEASURE_Y) +#define READ_Z1 (ADC_ON_12BIT | TSC2007_MEASURE_Z1) +#define READ_Z2 (ADC_ON_12BIT | TSC2007_MEASURE_Z2) +#define READ_X (ADC_ON_12BIT | TSC2007_MEASURE_X) +#define PWRDOWN (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN) + +struct ts_event { + u16 x; + u16 y; + u16 z1, z2; +}; + +struct tsc2007 { + struct input_dev *input; + char phys[32]; + + struct i2c_client *client; + + struct touchscreen_properties prop; + u16 model; + u16 x_plate_ohms; + u16 max_rt; + unsigned long poll_period; /* in jiffies */ + int fuzzx; + int fuzzy; + int fuzzz; + + struct gpio_desc *gpiod; + int irq; + + wait_queue_head_t wait; + bool stopped; + + int (*get_pendown_state)(struct device *); + void (*clear_penirq)(void); + + struct mutex mlock; +}; + +int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd); +u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc); +bool tsc2007_is_pen_down(struct tsc2007 *ts); + +#if IS_ENABLED(CONFIG_TOUCHSCREEN_TSC2007_IIO) +/* defined in tsc2007_iio.c */ +int tsc2007_iio_configure(struct tsc2007 *ts); +#else +static inline int tsc2007_iio_configure(struct tsc2007 *ts) +{ + return 0; +} +#endif /* CONFIG_TOUCHSCREEN_TSC2007_IIO */ + +#endif /* _TSC2007_H */ -- cgit v1.3.1