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, 41 insertions, 0 deletions

diff --git a/drivers/pmdomain/qcom/Kconfig b/drivers/pmdomain/qcom/Kconfig
new file mode 100644
index 000000000..4abd43a88
--- /dev/null
+++ b/drivers/pmdomain/qcom/Kconfig
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "Qualcomm PM Domains"
+
+config QCOM_CPR
+	tristate "Qualcomm Core Power Reduction (CPR) support"
+	depends on (ARCH_QCOM || COMPILE_TEST) && HAS_IOMEM
+	select PM_OPP
+	select REGMAP
+	help
+	  Say Y here to enable support for the CPR hardware found on Qualcomm
+	  SoCs like QCS404.
+
+	  This driver populates CPU OPPs tables and makes adjustments to the
+	  tables based on feedback from the CPR hardware. If you want to do
+	  CPUfrequency scaling say Y here.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called qcom-cpr
+
+config QCOM_RPMHPD
+	tristate "Qualcomm RPMh Power domain driver"
+	depends on QCOM_RPMH && QCOM_COMMAND_DB
+	help
+	  QCOM RPMh Power domain driver to support power-domains with
+	  performance states. The driver communicates a performance state
+	  value to RPMh which then translates it into corresponding voltage
+	  for the voltage rail.
+
+config QCOM_RPMPD
+	tristate "Qualcomm RPM Power domain driver"
+	depends on PM && OF
+	depends on QCOM_SMD_RPM
+	select PM_GENERIC_DOMAINS
+	select PM_GENERIC_DOMAINS_OF
+	help
+	  QCOM RPM Power domain driver to support power-domains with
+	  performance states. The driver communicates a performance state
+	  value to RPM which then translates it into corresponding voltage
+	  for the voltage rail.
+
+endmenu