x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

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) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 67 insertions, 0 deletions

diff --git a/sound/soc/sof/ipc3-priv.h b/sound/soc/sof/ipc3-priv.h
new file mode 100644
index 000000000..866c5f67b
--- /dev/null
+++ b/sound/soc/sof/ipc3-priv.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * Copyright(c) 2021 Intel Corporation
+ */
+
+#ifndef __SOUND_SOC_SOF_IPC3_PRIV_H
+#define __SOUND_SOC_SOF_IPC3_PRIV_H
+
+#include "sof-priv.h"
+
+/* IPC3 specific ops */
+extern const struct sof_ipc_pcm_ops ipc3_pcm_ops;
+extern const struct sof_ipc_tplg_ops ipc3_tplg_ops;
+extern const struct sof_ipc_tplg_control_ops tplg_ipc3_control_ops;
+extern const struct sof_ipc_fw_loader_ops ipc3_loader_ops;
+extern const struct sof_ipc_fw_tracing_ops ipc3_dtrace_ops;
+
+/* helpers for fw_ready and ext_manifest parsing */
+int sof_ipc3_get_ext_windows(struct snd_sof_dev *sdev,
+			     const struct sof_ipc_ext_data_hdr *ext_hdr);
+int sof_ipc3_get_cc_info(struct snd_sof_dev *sdev,
+			 const struct sof_ipc_ext_data_hdr *ext_hdr);
+int sof_ipc3_validate_fw_version(struct snd_sof_dev *sdev);
+
+/* dtrace position update */
+int ipc3_dtrace_posn_update(struct snd_sof_dev *sdev,
+			    struct sof_ipc_dma_trace_posn *posn);
+/* RX handler backend */
+void sof_ipc3_do_rx_work(struct snd_sof_dev *sdev, struct sof_ipc_cmd_hdr *hdr, void *msg_buf);
+
+/* dtrace platform callback wrappers */
+static inline int sof_dtrace_host_init(struct snd_sof_dev *sdev,
+				       struct snd_dma_buffer *dmatb,
+				       struct sof_ipc_dma_trace_params_ext *dtrace_params)
+{
+	const struct snd_sof_dsp_ops *dsp_ops = sdev->pdata->desc->ops;
+
+	if (dsp_ops->trace_init)
+		return dsp_ops->trace_init(sdev, dmatb, dtrace_params);
+
+	return 0;
+}
+
+static inline int sof_dtrace_host_release(struct snd_sof_dev *sdev)
+{
+	const struct snd_sof_dsp_ops *dsp_ops = sdev->pdata->desc->ops;
+
+	if (dsp_ops->trace_release)
+		return dsp_ops->trace_release(sdev);
+
+	return 0;
+}
+
+static inline int sof_dtrace_host_trigger(struct snd_sof_dev *sdev, int cmd)
+{
+	const struct snd_sof_dsp_ops *dsp_ops = sdev->pdata->desc->ops;
+
+	if (dsp_ops->trace_trigger)
+		return dsp_ops->trace_trigger(sdev, cmd);
+
+	return 0;
+}
+
+#endif