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, 54 insertions, 0 deletions

diff --git a/drivers/mfd/madera.h b/drivers/mfd/madera.h
new file mode 100644
index 000000000..900205678
--- /dev/null
+++ b/drivers/mfd/madera.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * MFD internals for Cirrus Logic Madera codecs
+ *
+ * Copyright 2015-2018 Cirrus Logic
+ */
+
+#ifndef MADERA_MFD_H
+#define MADERA_MFD_H
+
+#include <linux/of.h>
+#include <linux/pm.h>
+
+struct madera;
+
+extern const struct dev_pm_ops madera_pm_ops;
+extern const struct of_device_id madera_of_match[];
+
+int madera_dev_init(struct madera *madera);
+int madera_dev_exit(struct madera *madera);
+
+const char *madera_name_from_type(enum madera_type type);
+
+extern const struct regmap_config cs47l15_16bit_spi_regmap;
+extern const struct regmap_config cs47l15_32bit_spi_regmap;
+extern const struct regmap_config cs47l15_16bit_i2c_regmap;
+extern const struct regmap_config cs47l15_32bit_i2c_regmap;
+int cs47l15_patch(struct madera *madera);
+
+extern const struct regmap_config cs47l35_16bit_spi_regmap;
+extern const struct regmap_config cs47l35_32bit_spi_regmap;
+extern const struct regmap_config cs47l35_16bit_i2c_regmap;
+extern const struct regmap_config cs47l35_32bit_i2c_regmap;
+int cs47l35_patch(struct madera *madera);
+
+extern const struct regmap_config cs47l85_16bit_spi_regmap;
+extern const struct regmap_config cs47l85_32bit_spi_regmap;
+extern const struct regmap_config cs47l85_16bit_i2c_regmap;
+extern const struct regmap_config cs47l85_32bit_i2c_regmap;
+int cs47l85_patch(struct madera *madera);
+
+extern const struct regmap_config cs47l90_16bit_spi_regmap;
+extern const struct regmap_config cs47l90_32bit_spi_regmap;
+extern const struct regmap_config cs47l90_16bit_i2c_regmap;
+extern const struct regmap_config cs47l90_32bit_i2c_regmap;
+int cs47l90_patch(struct madera *madera);
+
+extern const struct regmap_config cs47l92_16bit_spi_regmap;
+extern const struct regmap_config cs47l92_32bit_spi_regmap;
+extern const struct regmap_config cs47l92_16bit_i2c_regmap;
+extern const struct regmap_config cs47l92_32bit_i2c_regmap;
+int cs47l92_patch(struct madera *madera);
+
+#endif