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, 117 insertions, 0 deletions

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
new file mode 100644
index 000000000..652557a5b
--- /dev/null
+++ b/drivers/iio/Kconfig
@@ -0,0 +1,117 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Industrial I/O subsystem configuration
+#
+
+menuconfig IIO
+	tristate "Industrial I/O support"
+	help
+	  The industrial I/O subsystem provides a unified framework for
+	  drivers for many different types of embedded sensors using a
+	  number of different physical interfaces (i2c, spi, etc).
+
+if IIO
+
+config IIO_BUFFER
+	bool "Enable buffer support within IIO"
+	select DMA_SHARED_BUFFER
+	help
+	  Provide core support for various buffer based data
+	  acquisition methods.
+
+if IIO_BUFFER
+	source "drivers/iio/buffer/Kconfig"
+endif # IIO_BUFFER
+
+config IIO_CONFIGFS
+	tristate "Enable IIO configuration via configfs"
+	select CONFIGFS_FS
+	help
+	  This allows configuring various IIO bits through configfs
+	  (e.g. software triggers). For more info see
+	  Documentation/iio/iio_configfs.rst.
+
+config IIO_GTS_HELPER
+	tristate
+
+config IIO_TRIGGER
+	bool "Enable triggered sampling support"
+	help
+	  Provides IIO core support for triggers.  Currently these
+	  are used to initialize capture of samples to push into
+	  buffers.  The triggers are effectively a 'capture
+	  data now' interrupt.
+
+config IIO_CONSUMERS_PER_TRIGGER
+	int "Maximum number of consumers per trigger"
+	depends on IIO_TRIGGER
+	default "2"
+	help
+	  This value controls the maximum number of consumers that a
+	  given trigger may handle. Default is 2.
+
+config IIO_SW_DEVICE
+	tristate "Enable software IIO device support"
+	select IIO_CONFIGFS
+	help
+	  Provides IIO core support for software devices. A software
+	  device can be created via configfs or directly by a driver
+	  using the API provided.
+
+config IIO_SW_TRIGGER
+	tristate "Enable software triggers support"
+	select IIO_CONFIGFS
+	help
+	  Provides IIO core support for software triggers. A software
+	  trigger can be created via configfs or directly by a driver
+	  using the API provided.
+
+config IIO_TRIGGERED_EVENT
+	tristate "Enable triggered events support"
+	select IIO_TRIGGER
+	help
+	  Provides helper functions for setting up triggered events.
+
+config IIO_BACKEND
+	tristate
+	help
+	  Framework to handle complex IIO aggregate devices. The typical
+	  architecture that can make use of this framework is to have one
+	  device as the frontend device which can be "linked" against one or
+	  multiple backend devices. The framework then makes it easy to get
+	  and control such backend devices.
+
+source "drivers/iio/accel/Kconfig"
+source "drivers/iio/adc/Kconfig"
+source "drivers/iio/addac/Kconfig"
+source "drivers/iio/afe/Kconfig"
+source "drivers/iio/amplifiers/Kconfig"
+source "drivers/iio/cdc/Kconfig"
+source "drivers/iio/chemical/Kconfig"
+source "drivers/iio/common/Kconfig"
+source "drivers/iio/dac/Kconfig"
+source "drivers/iio/dummy/Kconfig"
+source "drivers/iio/filter/Kconfig"
+source "drivers/iio/flow/Kconfig"
+source "drivers/iio/frequency/Kconfig"
+source "drivers/iio/gyro/Kconfig"
+source "drivers/iio/health/Kconfig"
+source "drivers/iio/humidity/Kconfig"
+source "drivers/iio/imu/Kconfig"
+source "drivers/iio/light/Kconfig"
+source "drivers/iio/magnetometer/Kconfig"
+source "drivers/iio/multiplexer/Kconfig"
+source "drivers/iio/orientation/Kconfig"
+source "drivers/iio/test/Kconfig"
+if IIO_TRIGGER
+   source "drivers/iio/trigger/Kconfig"
+endif #IIO_TRIGGER
+source "drivers/iio/position/Kconfig"
+source "drivers/iio/potentiometer/Kconfig"
+source "drivers/iio/potentiostat/Kconfig"
+source "drivers/iio/pressure/Kconfig"
+source "drivers/iio/proximity/Kconfig"
+source "drivers/iio/resolver/Kconfig"
+source "drivers/iio/temperature/Kconfig"
+
+endif # IIO