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/phy/spacemit/Kconfig b/drivers/phy/spacemit/Kconfig
new file mode 100644
index 000000000..5fdf18fce
--- /dev/null
+++ b/drivers/phy/spacemit/Kconfig
@@ -0,0 +1,41 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Phy drivers for SpacemiT platforms
+#
+config PHY_SPACEMIT_K1_PCIE
+	tristate "PCIe and combo PHY driver for the SpacemiT K1 SoC"
+	depends on ARCH_SPACEMIT || COMPILE_TEST
+	depends on COMMON_CLK
+	depends on HAS_IOMEM
+	depends on OF
+	select GENERIC_PHY
+	default ARCH_SPACEMIT
+	help
+	  Enable support for the PCIe and USB 3 combo PHY and two
+	  PCIe-only PHYs used in the SpacemiT K1 SoC.
+
+config PHY_SPACEMIT_K1_USB2
+	tristate "SpacemiT K1 USB 2.0 PHY support"
+	depends on (ARCH_SPACEMIT || COMPILE_TEST) && OF
+	depends on COMMON_CLK
+	depends on USB_COMMON
+	select GENERIC_PHY
+	help
+	  Enable this to support K1 USB 2.0 PHY driver. This driver takes care of
+	  enabling and clock setup and will be used by K1 udc/ehci/otg/xhci driver.
+
+config PHY_SPACEMIT_K3_COMMON_OPS
+	tristate
+	select MFD_SYSCON
+	select GENERIC_PHY
+
+config PHY_SPACEMIT_K3_COMBO_PHY
+	tristate "SpacemiT K3 USB3/PCIe PHY support"
+	depends on (ARCH_SPACEMIT || COMPILE_TEST) && OF
+	depends on COMMON_CLK
+	select PHY_SPACEMIT_K3_COMMON_OPS
+	help
+	  Enable this to support K3 USB3/PCIe combo PHY driver. This
+	  driver takes care of enabling and clock setup and will be used
+	  by K3 dwc3 driver.
+	  If unsure, say N.