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, 92 insertions, 0 deletions

diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
new file mode 100644
index 000000000..d7293977f
--- /dev/null
+++ b/drivers/soc/mediatek/Kconfig
@@ -0,0 +1,92 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# MediaTek SoC drivers
+#
+menu "MediaTek SoC drivers"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+
+config MTK_CMDQ
+	tristate "MediaTek CMDQ Support"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	select MAILBOX
+	select MTK_CMDQ_MBOX
+	select MTK_INFRACFG
+	help
+	  Say yes here to add support for the MediaTek Command Queue (CMDQ)
+	  driver. The CMDQ is used to help read/write registers with critical
+	  time limitation, such as updating display configuration during the
+	  vblank.
+
+config MTK_DEVAPC
+	tristate "Mediatek Device APC Support"
+	help
+	  Say yes here to enable support for Mediatek Device APC driver.
+	  This driver is mainly used to handle the violation which catches
+	  unexpected transaction.
+	  The violation information is logged for further analysis or
+	  countermeasures.
+
+config MTK_DVFSRC
+	tristate "MediaTek DVFSRC Support"
+	depends on ARCH_MEDIATEK
+	help
+	  Say yes here to add support for the MediaTek Dynamic Voltage
+	  and Frequency Scaling Resource Collector (DVFSRC): a HW
+	  IP found on many MediaTek SoCs, which is responsible for
+	  collecting DVFS requests from various SoC IPs, other than
+	  software, and performing bandwidth scaling to provide the
+	  best achievable performance-per-watt.
+
+config MTK_INFRACFG
+	bool "MediaTek INFRACFG Support"
+	select REGMAP
+	help
+	  Say yes here to add support for the MediaTek INFRACFG controller. The
+	  INFRACFG controller contains various infrastructure registers not
+	  directly associated to any device.
+
+config MTK_PMIC_WRAP
+	tristate "MediaTek PMIC Wrapper Support"
+	depends on RESET_CONTROLLER
+	depends on OF
+	select REGMAP
+	help
+	  Say yes here to add support for MediaTek PMIC Wrapper found
+	  on different MediaTek SoCs. The PMIC wrapper is a proprietary
+	  hardware to connect the PMIC.
+
+config MTK_REGULATOR_COUPLER
+	bool "MediaTek SoC Regulator Coupler" if COMPILE_TEST
+	default ARCH_MEDIATEK
+	depends on REGULATOR
+
+config MTK_MMSYS
+	tristate "MediaTek MMSYS Support"
+	default ARCH_MEDIATEK
+	depends on HAS_IOMEM
+	depends on MTK_CMDQ || MTK_CMDQ=n
+	help
+	  Say yes here to add support for the MediaTek Multimedia
+	  Subsystem (MMSYS).
+
+config MTK_SVS
+	tristate "MediaTek Smart Voltage Scaling(SVS)"
+	depends on NVMEM_MTK_EFUSE && NVMEM
+	help
+	  The Smart Voltage Scaling(SVS) engine is a piece of hardware
+	  which has several controllers(banks) for calculating suitable
+	  voltage to different power domains(CPU/GPU/CCI) according to
+	  chip process corner, temperatures and other factors. Then DVFS
+	  driver could apply SVS bank voltage to PMIC/Buck.
+
+config MTK_SOCINFO
+	tristate "MediaTek SoC Information"
+	default y
+	depends on NVMEM_MTK_EFUSE
+	select SOC_BUS
+	help
+	  The MediaTek SoC Information (mtk-socinfo) driver provides
+	  information about the SoC to the userspace including the
+	  manufacturer name, marketing name and soc name.
+
+endmenu