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/firewire/packet-header-definitions.h | 236 +++++++++++++++++++++++++++ 1 file changed, 236 insertions(+) create mode 100644 drivers/firewire/packet-header-definitions.h (limited to 'drivers/firewire/packet-header-definitions.h') diff --git a/drivers/firewire/packet-header-definitions.h b/drivers/firewire/packet-header-definitions.h new file mode 100644 index 000000000..87a5a3184 --- /dev/null +++ b/drivers/firewire/packet-header-definitions.h @@ -0,0 +1,236 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +// +// packet-header-definitions.h - The definitions of header fields for IEEE 1394 packet. +// +// Copyright (c) 2024 Takashi Sakamoto + +#ifndef _FIREWIRE_PACKET_HEADER_DEFINITIONS_H +#define _FIREWIRE_PACKET_HEADER_DEFINITIONS_H + +#include + +#define ASYNC_HEADER_QUADLET_COUNT 4 + +#define ASYNC_HEADER_Q0_DESTINATION_SHIFT 16 +#define ASYNC_HEADER_Q0_DESTINATION_MASK 0xffff0000 +#define ASYNC_HEADER_Q0_TLABEL_SHIFT 10 +#define ASYNC_HEADER_Q0_TLABEL_MASK 0x0000fc00 +#define ASYNC_HEADER_Q0_RETRY_SHIFT 8 +#define ASYNC_HEADER_Q0_RETRY_MASK 0x00000300 +#define ASYNC_HEADER_Q0_TCODE_SHIFT 4 +#define ASYNC_HEADER_Q0_TCODE_MASK 0x000000f0 +#define ASYNC_HEADER_Q0_PRIORITY_SHIFT 0 +#define ASYNC_HEADER_Q0_PRIORITY_MASK 0x0000000f +#define ASYNC_HEADER_Q1_SOURCE_SHIFT 16 +#define ASYNC_HEADER_Q1_SOURCE_MASK 0xffff0000 +#define ASYNC_HEADER_Q1_RCODE_SHIFT 12 +#define ASYNC_HEADER_Q1_RCODE_MASK 0x0000f000 +#define ASYNC_HEADER_Q1_RCODE_SHIFT 12 +#define ASYNC_HEADER_Q1_RCODE_MASK 0x0000f000 +#define ASYNC_HEADER_Q1_OFFSET_HIGH_SHIFT 0 +#define ASYNC_HEADER_Q1_OFFSET_HIGH_MASK 0x0000ffff +#define ASYNC_HEADER_Q3_DATA_LENGTH_SHIFT 16 +#define ASYNC_HEADER_Q3_DATA_LENGTH_MASK 0xffff0000 +#define ASYNC_HEADER_Q3_EXTENDED_TCODE_SHIFT 0 +#define ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK 0x0000ffff + +static inline unsigned int async_header_get_destination(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[0] & ASYNC_HEADER_Q0_DESTINATION_MASK) >> ASYNC_HEADER_Q0_DESTINATION_SHIFT; +} + +static inline unsigned int async_header_get_tlabel(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[0] & ASYNC_HEADER_Q0_TLABEL_MASK) >> ASYNC_HEADER_Q0_TLABEL_SHIFT; +} + +static inline unsigned int async_header_get_retry(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[0] & ASYNC_HEADER_Q0_RETRY_MASK) >> ASYNC_HEADER_Q0_RETRY_SHIFT; +} + +static inline unsigned int async_header_get_tcode(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[0] & ASYNC_HEADER_Q0_TCODE_MASK) >> ASYNC_HEADER_Q0_TCODE_SHIFT; +} + +static inline unsigned int async_header_get_priority(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[0] & ASYNC_HEADER_Q0_PRIORITY_MASK) >> ASYNC_HEADER_Q0_PRIORITY_SHIFT; +} + +static inline unsigned int async_header_get_source(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[1] & ASYNC_HEADER_Q1_SOURCE_MASK) >> ASYNC_HEADER_Q1_SOURCE_SHIFT; +} + +static inline unsigned int async_header_get_rcode(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[1] & ASYNC_HEADER_Q1_RCODE_MASK) >> ASYNC_HEADER_Q1_RCODE_SHIFT; +} + +static inline u64 async_header_get_offset(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + u32 hi = (header[1] & ASYNC_HEADER_Q1_OFFSET_HIGH_MASK) >> ASYNC_HEADER_Q1_OFFSET_HIGH_SHIFT; + return (((u64)hi) << 32) | ((u64)header[2]); +} + +static inline u32 async_header_get_quadlet_data(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return header[3]; +} + +static inline unsigned int async_header_get_data_length(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[3] & ASYNC_HEADER_Q3_DATA_LENGTH_MASK) >> ASYNC_HEADER_Q3_DATA_LENGTH_SHIFT; +} + +static inline unsigned int async_header_get_extended_tcode(const u32 header[ASYNC_HEADER_QUADLET_COUNT]) +{ + return (header[3] & ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK) >> ASYNC_HEADER_Q3_EXTENDED_TCODE_SHIFT; +} + +static inline void async_header_set_destination(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int destination) +{ + header[0] &= ~ASYNC_HEADER_Q0_DESTINATION_MASK; + header[0] |= (((u32)destination) << ASYNC_HEADER_Q0_DESTINATION_SHIFT) & ASYNC_HEADER_Q0_DESTINATION_MASK; +} + +static inline void async_header_set_tlabel(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int tlabel) +{ + header[0] &= ~ASYNC_HEADER_Q0_TLABEL_MASK; + header[0] |= (((u32)tlabel) << ASYNC_HEADER_Q0_TLABEL_SHIFT) & ASYNC_HEADER_Q0_TLABEL_MASK; +} + +static inline void async_header_set_retry(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int retry) +{ + header[0] &= ~ASYNC_HEADER_Q0_RETRY_MASK; + header[0] |= (((u32)retry) << ASYNC_HEADER_Q0_RETRY_SHIFT) & ASYNC_HEADER_Q0_RETRY_MASK; +} + +static inline void async_header_set_tcode(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int tcode) +{ + header[0] &= ~ASYNC_HEADER_Q0_TCODE_MASK; + header[0] |= (((u32)tcode) << ASYNC_HEADER_Q0_TCODE_SHIFT) & ASYNC_HEADER_Q0_TCODE_MASK; +} + +static inline void async_header_set_priority(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int priority) +{ + header[0] &= ~ASYNC_HEADER_Q0_PRIORITY_MASK; + header[0] |= (((u32)priority) << ASYNC_HEADER_Q0_PRIORITY_SHIFT) & ASYNC_HEADER_Q0_PRIORITY_MASK; +} + + +static inline void async_header_set_source(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int source) +{ + header[1] &= ~ASYNC_HEADER_Q1_SOURCE_MASK; + header[1] |= (((u32)source) << ASYNC_HEADER_Q1_SOURCE_SHIFT) & ASYNC_HEADER_Q1_SOURCE_MASK; +} + +static inline void async_header_set_rcode(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int rcode) +{ + header[1] &= ~ASYNC_HEADER_Q1_RCODE_MASK; + header[1] |= (((u32)rcode) << ASYNC_HEADER_Q1_RCODE_SHIFT) & ASYNC_HEADER_Q1_RCODE_MASK; +} + +static inline void async_header_set_offset(u32 header[ASYNC_HEADER_QUADLET_COUNT], u64 offset) +{ + u32 hi = (u32)(offset >> 32); + header[1] &= ~ASYNC_HEADER_Q1_OFFSET_HIGH_MASK; + header[1] |= (hi << ASYNC_HEADER_Q1_OFFSET_HIGH_SHIFT) & ASYNC_HEADER_Q1_OFFSET_HIGH_MASK; + header[2] = (u32)(offset & 0x00000000ffffffff); +} + +static inline void async_header_set_quadlet_data(u32 header[ASYNC_HEADER_QUADLET_COUNT], u32 quadlet_data) +{ + header[3] = quadlet_data; +} + +static inline void async_header_set_data_length(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int data_length) +{ + header[3] &= ~ASYNC_HEADER_Q3_DATA_LENGTH_MASK; + header[3] |= (((u32)data_length) << ASYNC_HEADER_Q3_DATA_LENGTH_SHIFT) & ASYNC_HEADER_Q3_DATA_LENGTH_MASK; +} + +static inline void async_header_set_extended_tcode(u32 header[ASYNC_HEADER_QUADLET_COUNT], + unsigned int extended_tcode) +{ + header[3] &= ~ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK; + header[3] |= (((u32)extended_tcode) << ASYNC_HEADER_Q3_EXTENDED_TCODE_SHIFT) & ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK; +} + +#define ISOC_HEADER_DATA_LENGTH_SHIFT 16 +#define ISOC_HEADER_DATA_LENGTH_MASK 0xffff0000 +#define ISOC_HEADER_TAG_SHIFT 14 +#define ISOC_HEADER_TAG_MASK 0x0000c000 +#define ISOC_HEADER_CHANNEL_SHIFT 8 +#define ISOC_HEADER_CHANNEL_MASK 0x00003f00 +#define ISOC_HEADER_TCODE_SHIFT 4 +#define ISOC_HEADER_TCODE_MASK 0x000000f0 +#define ISOC_HEADER_SY_SHIFT 0 +#define ISOC_HEADER_SY_MASK 0x0000000f + +static inline unsigned int isoc_header_get_data_length(u32 header) +{ + return (header & ISOC_HEADER_DATA_LENGTH_MASK) >> ISOC_HEADER_DATA_LENGTH_SHIFT; +} + +static inline unsigned int isoc_header_get_tag(u32 header) +{ + return (header & ISOC_HEADER_TAG_MASK) >> ISOC_HEADER_TAG_SHIFT; +} + +static inline unsigned int isoc_header_get_channel(u32 header) +{ + return (header & ISOC_HEADER_CHANNEL_MASK) >> ISOC_HEADER_CHANNEL_SHIFT; +} + +static inline unsigned int isoc_header_get_tcode(u32 header) +{ + return (header & ISOC_HEADER_TCODE_MASK) >> ISOC_HEADER_TCODE_SHIFT; +} + +static inline unsigned int isoc_header_get_sy(u32 header) +{ + return (header & ISOC_HEADER_SY_MASK) >> ISOC_HEADER_SY_SHIFT; +} + +static inline void isoc_header_set_data_length(u32 *header, unsigned int data_length) +{ + *header &= ~ISOC_HEADER_DATA_LENGTH_MASK; + *header |= (((u32)data_length) << ISOC_HEADER_DATA_LENGTH_SHIFT) & ISOC_HEADER_DATA_LENGTH_MASK; +} + +static inline void isoc_header_set_tag(u32 *header, unsigned int tag) +{ + *header &= ~ISOC_HEADER_TAG_MASK; + *header |= (((u32)tag) << ISOC_HEADER_TAG_SHIFT) & ISOC_HEADER_TAG_MASK; +} + +static inline void isoc_header_set_channel(u32 *header, unsigned int channel) +{ + *header &= ~ISOC_HEADER_CHANNEL_MASK; + *header |= (((u32)channel) << ISOC_HEADER_CHANNEL_SHIFT) & ISOC_HEADER_CHANNEL_MASK; +} + +static inline void isoc_header_set_tcode(u32 *header, unsigned int tcode) +{ + *header &= ~ISOC_HEADER_TCODE_MASK; + *header |= (((u32)tcode) << ISOC_HEADER_TCODE_SHIFT) & ISOC_HEADER_TCODE_MASK; +} + +static inline void isoc_header_set_sy(u32 *header, unsigned int sy) +{ + *header &= ~ISOC_HEADER_SY_MASK; + *header |= (((u32)sy) << ISOC_HEADER_SY_SHIFT) & ISOC_HEADER_SY_MASK; +} + +#endif // _FIREWIRE_PACKET_HEADER_DEFINITIONS_H -- cgit v1.3.1