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/cache/Kconfig | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 drivers/cache/Kconfig (limited to 'drivers/cache/Kconfig') diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig new file mode 100644 index 000000000..1518449d4 --- /dev/null +++ b/drivers/cache/Kconfig @@ -0,0 +1,56 @@ +# SPDX-License-Identifier: GPL-2.0 + +menuconfig CACHEMAINT_FOR_DMA + bool "Cache management for noncoherent DMA" + depends on RISCV + default y + help + These drivers implement support for noncoherent DMA master devices + on platforms that lack the standard CPU interfaces for this. + +if CACHEMAINT_FOR_DMA + +config AX45MP_L2_CACHE + bool "Andes Technology AX45MP L2 Cache controller" + select RISCV_NONSTANDARD_CACHE_OPS + help + Support for the L2 cache controller on Andes Technology AX45MP platforms. + +config SIFIVE_CCACHE + bool "Sifive Composable Cache controller" + depends on ARCH_SIFIVE || ARCH_STARFIVE + help + Support for the composable cache controller on SiFive platforms. + +config STARFIVE_STARLINK_CACHE + bool "StarFive StarLink Cache controller" + depends on ARCH_STARFIVE + depends on 64BIT + select RISCV_DMA_NONCOHERENT + select RISCV_NONSTANDARD_CACHE_OPS + help + Support for the StarLink cache controller IP from StarFive. + +endif #CACHEMAINT_FOR_DMA + +menuconfig CACHEMAINT_FOR_HOTPLUG + bool "Cache management for memory hot plug like operations" + depends on GENERIC_CPU_CACHE_MAINTENANCE + help + These drivers implement cache management for flows where it is necessary + to flush data from all host caches. + +if CACHEMAINT_FOR_HOTPLUG + +config HISI_SOC_HHA + tristate "HiSilicon Hydra Home Agent (HHA) device driver" + depends on (ARM64 && ACPI) || COMPILE_TEST + help + The Hydra Home Agent (HHA) is responsible for cache coherency + on the SoC. This drivers enables the cache maintenance functions of + the HHA. + + This driver can be built as a module. If so, the module will be + called hisi_soc_hha. + +endif #CACHEMAINT_FOR_HOTPLUG -- cgit v1.3.1