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/bluetooth/btbcm.h | 117 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 drivers/bluetooth/btbcm.h (limited to 'drivers/bluetooth/btbcm.h') diff --git a/drivers/bluetooth/btbcm.h b/drivers/bluetooth/btbcm.h new file mode 100644 index 000000000..b4cb24231 --- /dev/null +++ b/drivers/bluetooth/btbcm.h @@ -0,0 +1,117 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * + * Bluetooth support for Broadcom devices + * + * Copyright (C) 2015 Intel Corporation + */ + +#define BCM_UART_CLOCK_48MHZ 0x01 +#define BCM_UART_CLOCK_24MHZ 0x02 + +struct bcm_update_uart_baud_rate { + __le16 zero; + __le32 baud_rate; +} __packed; + +struct bcm_write_uart_clock_setting { + __u8 type; +} __packed; + +struct bcm_set_sleep_mode { + __u8 sleep_mode; + __u8 idle_host; + __u8 idle_dev; + __u8 bt_wake_active; + __u8 host_wake_active; + __u8 allow_host_sleep; + __u8 combine_modes; + __u8 tristate_control; + __u8 usb_auto_sleep; + __u8 usb_resume_timeout; + __u8 break_to_host; + __u8 pulsed_host_wake; +} __packed; + +struct bcm_set_pcm_int_params { + __u8 routing; + __u8 rate; + __u8 frame_sync; + __u8 sync_mode; + __u8 clock_mode; +} __packed; + +struct bcm_set_pcm_format_params { + __u8 lsb_first; + __u8 fill_value; + __u8 fill_method; + __u8 fill_num; + __u8 right_justify; +} __packed; + +#if IS_ENABLED(CONFIG_BT_BCM) + +int btbcm_check_bdaddr(struct hci_dev *hdev); +int btbcm_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr); +int btbcm_patchram(struct hci_dev *hdev, const struct firmware *fw); +int btbcm_read_pcm_int_params(struct hci_dev *hdev, + struct bcm_set_pcm_int_params *params); +int btbcm_write_pcm_int_params(struct hci_dev *hdev, + const struct bcm_set_pcm_int_params *params); + +int btbcm_setup_patchram(struct hci_dev *hdev); +int btbcm_setup_apple(struct hci_dev *hdev); + +int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode); +int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode); + +#else + +static inline int btbcm_check_bdaddr(struct hci_dev *hdev) +{ + return -EOPNOTSUPP; +} + +static inline int btbcm_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr) +{ + return -EOPNOTSUPP; +} + +static inline int btbcm_read_pcm_int_params(struct hci_dev *hdev, + struct bcm_set_pcm_int_params *params) +{ + return -EOPNOTSUPP; +} + +static inline int btbcm_write_pcm_int_params(struct hci_dev *hdev, + const struct bcm_set_pcm_int_params *params) +{ + return -EOPNOTSUPP; +} + +static inline int btbcm_patchram(struct hci_dev *hdev, const struct firmware *fw) +{ + return -EOPNOTSUPP; +} + +static inline int btbcm_setup_patchram(struct hci_dev *hdev) +{ + return 0; +} + +static inline int btbcm_setup_apple(struct hci_dev *hdev) +{ + return 0; +} + +static inline int btbcm_initialize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode) +{ + return 0; +} + +static inline int btbcm_finalize(struct hci_dev *hdev, bool *fw_load_done, bool use_autobaud_mode) +{ + return 0; +} + +#endif -- cgit v1.3.1