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, 168 insertions, 0 deletions

diff --git a/drivers/ssb/Kconfig b/drivers/ssb/Kconfig
new file mode 100644
index 000000000..1cf1a9895
--- /dev/null
+++ b/drivers/ssb/Kconfig
@@ -0,0 +1,168 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config SSB_POSSIBLE
+	bool
+	depends on HAS_IOMEM && HAS_DMA
+	default y
+
+menuconfig SSB
+	tristate "Sonics Silicon Backplane support"
+	depends on SSB_POSSIBLE
+	help
+	  Support for the Sonics Silicon Backplane bus.
+	  You only need to enable this option, if you are
+	  configuring a kernel for an embedded system with
+	  this bus.
+	  It will be auto-selected if needed in other
+	  environments.
+
+	  The module will be called ssb.
+
+	  If unsure, say N.
+
+if SSB
+
+# Common SPROM support routines
+config SSB_SPROM
+	bool
+
+# Support for Block-I/O. SELECT this from the driver that needs it.
+config SSB_BLOCKIO
+	bool
+	depends on SSB
+
+config SSB_PCIHOST_POSSIBLE
+	bool
+	depends on SSB && (PCI = y || PCI = SSB) && (PCI_DRIVERS_LEGACY || !MIPS)
+	default y
+
+config SSB_PCIHOST
+	bool "Support for SSB on PCI-bus host"
+	depends on SSB_PCIHOST_POSSIBLE
+	select SSB_SPROM
+	default y
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a PCI device.
+
+	  If unsure, say Y
+
+config SSB_B43_PCI_BRIDGE
+	bool
+	depends on SSB_PCIHOST
+	default n
+
+config SSB_PCMCIAHOST_POSSIBLE
+	bool
+	depends on SSB && (PCMCIA = y || PCMCIA = SSB)
+	default y
+
+config SSB_PCMCIAHOST
+	bool "Support for SSB on PCMCIA-bus host"
+	depends on SSB_PCMCIAHOST_POSSIBLE
+	select SSB_SPROM
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a PCMCIA device.
+
+	  If unsure, say N
+
+config SSB_SDIOHOST_POSSIBLE
+	bool
+	depends on SSB && (MMC = y || MMC = SSB)
+	default y
+
+config SSB_SDIOHOST
+	bool "Support for SSB on SDIO-bus host"
+	depends on SSB_SDIOHOST_POSSIBLE
+	help
+	  Support for a Sonics Silicon Backplane on top
+	  of a SDIO device.
+
+	  If unsure, say N
+
+config SSB_HOST_SOC
+	bool "Support for SSB bus on SoC"
+	depends on SSB && BCM47XX_NVRAM
+	select SSB_SPROM
+	help
+	  Host interface for a SSB directly mapped into memory. This is
+	  for some Broadcom SoCs from the BCM47xx and BCM53xx lines.
+
+	  If unsure, say N
+
+config SSB_SERIAL
+	bool
+	depends on SSB
+	# ChipCommon and ExtIf serial support routines.
+
+config SSB_DRIVER_PCICORE_POSSIBLE
+	bool
+	depends on SSB_PCIHOST
+	default y
+
+config SSB_DRIVER_PCICORE
+	bool "SSB PCI core driver"
+	depends on SSB_DRIVER_PCICORE_POSSIBLE
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom PCI core.
+
+	  If unsure, say Y
+
+config SSB_PCICORE_HOSTMODE
+	bool "Hostmode support for SSB PCI core"
+	depends on SSB_DRIVER_PCICORE && SSB_DRIVER_MIPS && SSB = y
+	help
+	  PCIcore hostmode operation (external PCI bus).
+
+config SSB_DRIVER_MIPS
+	bool "SSB Broadcom MIPS core driver"
+	depends on SSB && MIPS
+	select SSB_SERIAL
+	select SSB_SFLASH
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom MIPS core.
+
+	  If unsure, say N
+
+config SSB_SFLASH
+	bool "SSB serial flash support"
+	depends on SSB_DRIVER_MIPS
+	default y
+
+# Assumption: We are on embedded, if we compile the MIPS core.
+config SSB_EMBEDDED
+	bool
+	depends on SSB_DRIVER_MIPS
+	depends on PCI=n || SSB_PCICORE_HOSTMODE
+	default y
+
+config SSB_DRIVER_EXTIF
+	bool "SSB Broadcom EXTIF core driver"
+	depends on SSB_DRIVER_MIPS
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom EXTIF core.
+
+	  If unsure, say N
+
+config SSB_DRIVER_GIGE
+	bool "SSB Broadcom Gigabit Ethernet driver"
+	depends on SSB_PCIHOST_POSSIBLE && SSB_EMBEDDED && MIPS
+	help
+	  Driver for the Sonics Silicon Backplane attached
+	  Broadcom Gigabit Ethernet.
+
+	  If unsure, say N
+
+config SSB_DRIVER_GPIO
+	bool "SSB GPIO driver"
+	depends on SSB && GPIOLIB
+	select IRQ_DOMAIN if SSB_EMBEDDED
+	help
+	  Driver to provide access to the GPIO pins on the bus.
+
+	  If unsure, say N
+
+endif # SSB