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 --- net/can/Kconfig | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 net/can/Kconfig (limited to 'net/can/Kconfig') diff --git a/net/can/Kconfig b/net/can/Kconfig new file mode 100644 index 000000000..abbb4be7a --- /dev/null +++ b/net/can/Kconfig @@ -0,0 +1,73 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Controller Area Network (CAN) network layer core configuration +# + +menuconfig CAN + tristate "CAN bus subsystem support" + select SKB_EXTENSIONS + help + Controller Area Network (CAN) is a slow (up to 1Mbit/s) serial + communications protocol. Development of the CAN bus started in + 1983 at Robert Bosch GmbH, and the protocol was officially + released in 1986. The CAN bus was originally mainly for automotive, + but is now widely used in marine (NMEA2000), industrial, and medical + applications. More information on the CAN network protocol family + PF_CAN is contained in . + + If you want CAN support you should say Y here and also to the + specific driver for your controller(s) under the Network device + support section. + +if CAN + +config CAN_RAW + tristate "Raw CAN Protocol (raw access with CAN-ID filtering)" + default y + help + The raw CAN protocol option offers access to the CAN bus via + the BSD socket API. You probably want to use the raw socket in + most cases where no higher level protocol is being used. The raw + socket has several filter options e.g. ID masking / error frames. + To receive/send raw CAN messages, use AF_CAN with protocol CAN_RAW. + +config CAN_BCM + tristate "Broadcast Manager CAN Protocol (with content filtering)" + default y + help + The Broadcast Manager offers content filtering, timeout monitoring, + sending of RTR frames, and cyclic CAN messages without permanent user + interaction. The BCM can be 'programmed' via the BSD socket API and + informs you on demand e.g. only on content updates / timeouts. + You probably want to use the bcm socket in most cases where cyclic + CAN messages are used on the bus (e.g. in automotive environments). + To use the Broadcast Manager, use AF_CAN with protocol CAN_BCM. + +config CAN_GW + tristate "CAN Gateway/Router (with netlink configuration)" + default y + help + The CAN Gateway/Router is used to route (and modify) CAN frames. + It is based on the PF_CAN core infrastructure for msg filtering and + msg sending and can optionally modify routed CAN frames on the fly. + CAN frames can be routed between CAN network interfaces (one hop). + They can be modified with AND/OR/XOR/SET operations as configured + by the netlink configuration interface known e.g. from iptables. + +source "net/can/j1939/Kconfig" + +config CAN_ISOTP + tristate "ISO 15765-2 CAN transport protocol" + help + CAN Transport Protocols offer support for segmented Point-to-Point + communication between CAN nodes via two defined CAN Identifiers. + This protocol driver implements segmented data transfers for CAN CC + (aka Classical CAN, CAN 2.0B) and CAN FD frame types which were + introduced with ISO 15765-2:2016. + As CAN frames can only transport a small amount of data bytes + (max. 8 bytes for CAN CC and max. 64 bytes for CAN FD) this + segmentation is needed to transport longer Protocol Data Units (PDU) + as needed e.g. for vehicle diagnosis (UDS, ISO 14229) or IP-over-CAN + traffic. + +endif -- cgit v1.3.1