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/devfreq/event/Kconfig | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 drivers/devfreq/event/Kconfig (limited to 'drivers/devfreq/event/Kconfig') diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig new file mode 100644 index 000000000..878825372 --- /dev/null +++ b/drivers/devfreq/event/Kconfig @@ -0,0 +1,42 @@ +# SPDX-License-Identifier: GPL-2.0-only +menuconfig PM_DEVFREQ_EVENT + bool "DEVFREQ-Event device Support" + help + The devfreq-event device provide the raw data and events which + indicate the current state of devfreq-event device. The provided + data from devfreq-event device is used to monitor the state of + device and determine the suitable size of resource to reduce the + wasted resource. + + The devfreq-event device can support the various type of events + (e.g., raw data, utilization, latency, bandwidth). The events + may be used by devfreq governor and other subsystem. + +if PM_DEVFREQ_EVENT + +config DEVFREQ_EVENT_EXYNOS_NOCP + tristate "Exynos NoC (Network On Chip) Probe DEVFREQ event Driver" + depends on ARCH_EXYNOS || COMPILE_TEST + select PM_OPP + select REGMAP_MMIO + help + This add the devfreq-event driver for Exynos SoC. It provides NoC + (Network on Chip) Probe counters to measure the bandwidth of AXI bus. + +config DEVFREQ_EVENT_EXYNOS_PPMU + tristate "Exynos PPMU (Platform Performance Monitoring Unit) DEVFREQ event Driver" + depends on ARCH_EXYNOS || COMPILE_TEST + select PM_OPP + help + This add the devfreq-event driver for Exynos SoC. It provides PPMU + (Platform Performance Monitoring Unit) counters to estimate the + utilization of each module. + +config DEVFREQ_EVENT_ROCKCHIP_DFI + tristate "ROCKCHIP DFI DEVFREQ event Driver" + depends on ARCH_ROCKCHIP || COMPILE_TEST + help + This add the devfreq-event driver for Rockchip SoC. It provides DFI + (DDR Monitor Module) driver to count ddr load. + +endif # PM_DEVFREQ_EVENT -- cgit v1.3.1