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/thunderbolt/Kconfig | 78 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 drivers/thunderbolt/Kconfig (limited to 'drivers/thunderbolt/Kconfig') diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig new file mode 100644 index 000000000..294b3227a --- /dev/null +++ b/drivers/thunderbolt/Kconfig @@ -0,0 +1,78 @@ +# SPDX-License-Identifier: GPL-2.0-only +menuconfig USB4 + tristate "Unified support for USB4 and Thunderbolt" + depends on PCI + select APPLE_PROPERTIES if EFI_STUB && X86 + select CRC32 + select CRYPTO_LIB_SHA256 + select CRYPTO_LIB_UTILS + select NVMEM + help + USB4 and Thunderbolt driver. USB4 is the public specification + based on the Thunderbolt 3 protocol. This driver is required if + you want to hotplug Thunderbolt and USB4 compliant devices on + Apple hardware or on PCs with Intel Falcon Ridge or newer. + + To compile this driver a module, choose M here. The module will be + called thunderbolt. + +if USB4 + +config USB4_CONFIGFS + def_tristate USB4 + depends on CONFIGFS_FS && !(USB4=y && CONFIGFS_FS=m) + +config USB4_DEBUGFS_WRITE + bool "Enable write by debugfs to configuration spaces (DANGEROUS)" + help + Enables writing to device configuration registers through + debugfs interface. You can use tools such as Thunderbolt/USB4 + debugging tools to access these registers. For more + information see: + + https://github.com/intel/tbtools + + Only enable this if you know what you are doing! Never enable + this for production systems or distro kernels. + +config USB4_DEBUGFS_MARGINING + bool "Expose receiver lane margining operations under USB4 ports and retimers (DANGEROUS)" + depends on DEBUG_FS + depends on USB4_DEBUGFS_WRITE + help + Enables hardware and software based receiver lane margining + support under each USB4 port and retimer, including retimers + on the other side of the cable. Used for electrical quality + and robustness validation during manufacturing. Should not be + enabled by distro kernels. + +config USB4_KUNIT_TEST + bool "KUnit tests" if !KUNIT_ALL_TESTS + depends on USB4 && KUNIT=y + default KUNIT_ALL_TESTS + +config USB4_DMA_TEST + tristate "DMA traffic test driver" + depends on DEBUG_FS + help + This allows sending and receiving DMA traffic through loopback + connection. Loopback connection can be done by either special + dongle that has TX/RX lines crossed, or by simply connecting a + cable back to the host. Only enable this if you know what you + are doing. Normal users and distro kernels should say N here. + + To compile this driver a module, choose M here. The module will be + called thunderbolt_dma_test. + +config USB4_STREAM + tristate "Stream data over Thunderbolt/USB4 cable" + depends on USB4_CONFIGFS + help + This adds support for USB4STREAM protocol that allows two + hosts to stream data directly over Thunderbolt/USB4 cable + through /dev/tbstreamX devices. + + To compile this driver a module, choose M here. The module will be + called thunderbolt_stream. + +endif # USB4 -- cgit v1.3.1