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, 69 insertions, 0 deletions

diff --git a/drivers/iio/amplifiers/Kconfig b/drivers/iio/amplifiers/Kconfig
new file mode 100644
index 000000000..9e24421b5
--- /dev/null
+++ b/drivers/iio/amplifiers/Kconfig
@@ -0,0 +1,69 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Gain Amplifiers, etc.
+#
+# When adding new entries keep the list in alphabetical order
+
+menu "Amplifiers"
+
+config AD8366
+	tristate "Analog Devices AD8366 and similar Gain Amplifiers"
+	depends on SPI
+	depends on GPIOLIB
+	select BITREVERSE
+	help
+	  Say yes here to build support for Analog Devices AD8366 and similar
+	  gain amplifiers. This driver supports the following gain amplifiers
+	  from Analog Devices:
+	    AD8366 Dual-Digital Variable Gain Amplifier (VGA)
+	    ADA4961 BiCMOS RF Digital Gain Amplifier (DGA)
+	    ADL5240 Digitally controlled variable gain amplifier (VGA)
+	    ADRF5702: 0.125 dB LSB, 8-Bit, Silicon Digital Attenuator
+	    ADRF5703: 0.25 dB LSB, 7-Bit, Silicon Digital Attenuator
+	    ADRF5720: 0.5 dB LSB, 6-Bit, Silicon Digital Attenuator
+	    ADRF5730: 0.5 dB LSB, 6-Bit, Silicon Digital Attenuator
+	    ADRF5731: 2 dB LSB, 4-Bit, Silicon Digital Attenuator
+	    HMC271A: 1dB LSB 5-Bit Digital Attenuator SMT
+	    HMC792A 0.25 dB LSB GaAs MMIC 6-Bit Digital Attenuator
+	    HMC1018A: 1.0 dB LSB GaAs MMIC 5-BIT Digital Attenuator
+	    HMC1019A: 0.5 dB LSB GaAs MMIC 5-BIT Digital Attenuator
+	    HMC1119 0.25 dB LSB, 7-Bit, Silicon Digital Attenuator
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad8366.
+
+config ADA4250
+	tristate "Analog Devices ADA4250 Instrumentation Amplifier"
+	depends on SPI
+	select REGMAP_SPI
+	help
+	  Say yes here to build support for Analog Devices ADA4250
+	  SPI Amplifier's support. The driver provides direct access via
+	  sysfs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ada4250.
+
+config ADL8113
+	tristate "Analog Devices ADL8113 Low Noise Amplifier"
+	depends on GPIOLIB
+	help
+	  Say yes here to build support for Analog Devices ADL8113 Low Noise
+	  Amplifier with integrated bypass switches. The device supports four
+	  operation modes controlled by GPIO pins: internal amplifier,
+	  internal bypass, and two external bypass modes.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called adl8113.
+
+config HMC425
+	tristate "Analog Devices HMC425A and similar GPIO Gain Amplifiers"
+	depends on GPIOLIB
+	help
+	  Say yes here to build support for Analog Devices HMC425A and similar
+	  gain amplifiers or step attenuators.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called hmc425a.
+
+endmenu