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 --- Documentation/ABI/testing/debugfs-hisi-hpre | 200 ++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-hisi-hpre (limited to 'Documentation/ABI/testing/debugfs-hisi-hpre') diff --git a/Documentation/ABI/testing/debugfs-hisi-hpre b/Documentation/ABI/testing/debugfs-hisi-hpre new file mode 100644 index 000000000..5a137f701 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-hisi-hpre @@ -0,0 +1,200 @@ +What: /sys/kernel/debug/hisi_hpre//cluster[0-3]/regs +Date: Sep 2019 +Contact: linux-crypto@vger.kernel.org +Description: Dump debug registers from the HPRE cluster. + Only available for PF. + +What: /sys/kernel/debug/hisi_hpre//cluster[0-3]/cluster_ctrl +Date: Sep 2019 +Contact: linux-crypto@vger.kernel.org +Description: Write the HPRE core selection in the cluster into this file, + and then we can read the debug information of the core. + Only available for PF. + +What: /sys/kernel/debug/hisi_hpre//rdclr_en +Date: Sep 2019 +Contact: linux-crypto@vger.kernel.org +Description: HPRE cores debug registers read clear control. 1 means enable + register read clear, otherwise 0. Writing to this file has no + functional effect, only enable or disable counters clear after + reading of these registers. + Only available for PF. + +What: /sys/kernel/debug/hisi_hpre//current_qm +Date: Sep 2019 +Contact: linux-crypto@vger.kernel.org +Description: One HPRE controller has one PF and multiple VFs, each function + has a QM. Select the QM which below qm refers to. + Only available for PF. + +What: /sys/kernel/debug/hisi_hpre//alg_qos +Date: Jun 2021 +Contact: linux-crypto@vger.kernel.org +Description: The is related the function for PF and VF. + HPRE driver supports to configure each function's QoS, the driver + supports to write value to alg_qos in the host. Such as + "echo value > alg_qos". The qos value is 1~1000, means + 1/1000~1000/1000 of total QoS. The driver reading alg_qos to + get related QoS in the host and VM, Such as "cat alg_qos". + +What: /sys/kernel/debug/hisi_hpre//regs +Date: Sep 2019 +Contact: linux-crypto@vger.kernel.org +Description: Dump debug registers from the HPRE. + Only available for PF. + +What: /sys/kernel/debug/hisi_hpre//qm/regs +Date: Sep 2019 +Contact: linux-crypto@vger.kernel.org +Description: Dump debug registers from the QM. + Available for PF and VF in host. VF in guest currently only + has one debug register. + +What: /sys/kernel/debug/hisi_hpre//dev_usage +Date: Mar 2026 +Contact: linux-crypto@vger.kernel.org +Description: Query the real-time bandwidth usage of device. + Returns the bandwidth usage of each channel on the device. + The returned number is in percentage. + +What: /sys/kernel/debug/hisi_hpre//qm/current_q +Date: Sep 2019 +Contact: linux-crypto@vger.kernel.org +Description: One QM may contain multiple queues. Select specific queue to + show its debug registers in above regs. + Only available for PF. + +What: /sys/kernel/debug/hisi_hpre//qm/clear_enable +Date: Sep 2019 +Contact: linux-crypto@vger.kernel.org +Description: QM debug registers(regs) read clear control. 1 means enable + register read clear, otherwise 0. + Writing to this file has no functional effect, only enable or + disable counters clear after reading of these registers. + Only available for PF. + +What: /sys/kernel/debug/hisi_hpre//qm/err_irq +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the number of invalid interrupts for + QM task completion. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//qm/aeq_irq +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the number of QM async event queue interrupts. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//qm/abnormal_irq +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the number of interrupts for QM abnormal event. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//qm/create_qp_err +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the number of queue allocation errors. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//qm/mb_err +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the number of failed QM mailbox commands. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//qm/status +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the status of the QM. + Two states: work, stop. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//qm/diff_regs +Date: Mar 2022 +Contact: linux-crypto@vger.kernel.org +Description: QM debug registers(regs) read hardware register value. This + node is used to show the change of the qm register values. This + node can be help users to check the change of register values. + +What: /sys/kernel/debug/hisi_hpre//qm/qm_state +Date: Jan 2024 +Contact: linux-crypto@vger.kernel.org +Description: Dump the state of the device. + 0: busy, 1: idle. + Only available for PF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//qm/dev_timeout +Date: Feb 2024 +Contact: linux-crypto@vger.kernel.org +Description: Set the wait time when stop queue fails. Available for both PF + and VF, and take no other effect on HPRE. + 0: not wait(default), others value: wait dev_timeout * 20 microsecond. + +What: /sys/kernel/debug/hisi_hpre//qm/dev_state +Date: Feb 2024 +Contact: linux-crypto@vger.kernel.org +Description: Dump the stop queue status of the QM. The default value is 0, + if dev_timeout is set, when stop queue fails, the dev_state + will return non-zero value. Available for both PF and VF, + and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//hpre_dfx/diff_regs +Date: Mar 2022 +Contact: linux-crypto@vger.kernel.org +Description: HPRE debug registers(regs) read hardware register value. This + node is used to show the change of the register values. This + node can be help users to check the change of register values. + +What: /sys/kernel/debug/hisi_hpre//hpre_dfx/send_cnt +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the total number of sent requests. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//hpre_dfx/recv_cnt +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the total number of received requests. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//hpre_dfx/send_busy_cnt +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the total number of requests sent + with returning busy. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//hpre_dfx/send_fail_cnt +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the total number of completed but error requests. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//hpre_dfx/invalid_req_cnt +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the total number of invalid requests being received. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//hpre_dfx/overtime_thrhld +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Set the threshold time for counting the request which is + processed longer than the threshold. + 0: disable(default), 1: 1 microsecond. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//hpre_dfx/over_thrhld_cnt +Date: Apr 2020 +Contact: linux-crypto@vger.kernel.org +Description: Dump the total number of time out requests. + Available for both PF and VF, and take no other effect on HPRE. + +What: /sys/kernel/debug/hisi_hpre//cap_regs +Date: Oct 2024 +Contact: linux-crypto@vger.kernel.org +Description: Dump the values of the qm and hpre capability bit registers and + support the query of device specifications to facilitate fault locating. + Available for both PF and VF, and take no other effect on HPRE. -- cgit v1.3.1