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, 36 insertions, 0 deletions

diff --git a/drivers/reset/spacemit/Kconfig b/drivers/reset/spacemit/Kconfig
new file mode 100644
index 000000000..545d6b41c
--- /dev/null
+++ b/drivers/reset/spacemit/Kconfig
@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menu "Reset support for SpacemiT platforms"
+	depends on ARCH_SPACEMIT || COMPILE_TEST
+
+config RESET_SPACEMIT_COMMON
+	tristate
+	select AUXILIARY_BUS
+	help
+	  Common reset controller infrastructure for SpacemiT SoCs.
+	  This provides shared code and helper functions used by
+	  reset drivers for various SpacemiT SoC families.
+
+config RESET_SPACEMIT_K1
+	tristate "Support for SpacemiT K1 SoC"
+	depends on SPACEMIT_K1_CCU
+	select RESET_SPACEMIT_COMMON
+	default SPACEMIT_K1_CCU
+	help
+	  Support for reset controller in SpacemiT K1 SoC.
+	  This driver works with the SpacemiT K1 clock controller
+	  unit (CCU) driver to provide reset control functionality
+	  for various peripherals and subsystems in the SoC.
+
+config RESET_SPACEMIT_K3
+	tristate "Support for SpacemiT K3 SoC"
+	depends on SPACEMIT_K3_CCU
+	select RESET_SPACEMIT_COMMON
+	default SPACEMIT_K3_CCU
+	help
+	  Support for reset controller in SpacemiT K3 SoC.
+	  This driver works with the SpacemiT K3 clock controller
+	  unit (CCU) driver to provide reset control functionality
+	  for various peripherals and subsystems in the SoC.
+
+endmenu