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, 59 insertions, 0 deletions

diff --git a/drivers/pmdomain/mediatek/Kconfig b/drivers/pmdomain/mediatek/Kconfig
new file mode 100644
index 000000000..a2eb704a7
--- /dev/null
+++ b/drivers/pmdomain/mediatek/Kconfig
@@ -0,0 +1,59 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menu "MediaTek PM Domains"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+
+config MTK_SCPSYS
+	bool "MediaTek SCPSYS Support"
+	default ARCH_MEDIATEK
+	depends on OF
+	select REGMAP
+	select MTK_INFRACFG
+	select PM_GENERIC_DOMAINS if PM
+	help
+	  Say yes here to add support for the MediaTek SCPSYS power domain
+	  driver.
+
+config MTK_SCPSYS_PM_DOMAINS
+	bool "MediaTek SCPSYS generic power domain"
+	default ARCH_MEDIATEK
+	depends on PM
+	select PM_GENERIC_DOMAINS
+	select REGMAP
+	help
+	  Say y here to enable power domain support.
+	  In order to meet high performance and low power requirements, the System
+	  Control Processor System (SCPSYS) has several power management related
+	  tasks in the system.
+
+config MTK_MFG_PM_DOMAIN
+	bool "MediaTek MFlexGraphics power domain"
+	default ARCH_MEDIATEK
+	depends on PM
+	depends on OF
+	depends on COMMON_CLK
+	select MAILBOX
+	select PM_GENERIC_DOMAINS
+	imply MTK_GPUEB_MBOX
+	help
+	  Say y or m here to enable the power domains driver for MediaTek
+	  MFlexGraphics. This driver allows for power and frequency control of
+	  GPUs on MediaTek SoCs such as the MT8196 or MT6991.
+
+	  This driver is required for the Mali GPU to work at all on MT8196 and
+	  MT6991.
+
+endmenu
+
+config AIROHA_CPU_PM_DOMAIN
+	tristate "Airoha CPU power domain"
+	default ARCH_AIROHA
+	depends on ARCH_AIROHA || COMPILE_TEST
+	depends on HAVE_ARM_SMCCC
+	depends on PM
+	select PM_GENERIC_DOMAINS
+	help
+	  Say y here to enable CPU power domain support for Airoha SoC.
+
+	  CPU frequency and power is controlled by ATF with SMC command to
+	  set performance states.