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, 138 insertions, 0 deletions

diff --git a/drivers/nvme/target/Kconfig b/drivers/nvme/target/Kconfig
new file mode 100644
index 000000000..69bde2701
--- /dev/null
+++ b/drivers/nvme/target/Kconfig
@@ -0,0 +1,138 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config NVME_TARGET
+	tristate "NVMe Target support"
+	depends on BLOCK
+	select CONFIGFS_FS
+	select NVME_KEYRING if NVME_TARGET_TCP_TLS
+	select KEYS if NVME_TARGET_TCP_TLS
+	select SGL_ALLOC
+	help
+	  This enabled target side support for the NVMe protocol, that is
+	  it allows the Linux kernel to implement NVMe subsystems and
+	  controllers and export Linux block devices as NVMe namespaces.
+	  You need to select at least one of the transports below to make this
+	  functionality useful.
+
+	  To configure the NVMe target you probably want to use the nvmetcli
+	  tool from http://git.infradead.org/users/hch/nvmetcli.git.
+
+config NVME_TARGET_DEBUGFS
+        bool "NVMe Target debugfs support"
+	depends on NVME_TARGET
+	help
+	  This enables debugfs support to display the connected controllers
+	  to each subsystem
+
+	  If unsure, say N.
+
+config NVME_TARGET_PASSTHRU
+	bool "NVMe Target Passthrough support"
+	depends on NVME_TARGET
+	depends on NVME_CORE=y || NVME_CORE=NVME_TARGET
+	help
+	  This enables target side NVMe passthru controller support for the
+	  NVMe Over Fabrics protocol. It allows for hosts to manage and
+	  directly access an actual NVMe controller residing on the target
+	  side, including executing Vendor Unique Commands.
+
+	  If unsure, say N.
+
+config NVME_TARGET_LOOP
+	tristate "NVMe loopback device support"
+	depends on NVME_TARGET
+	select NVME_FABRICS
+	select SG_POOL
+	help
+	  This enables the NVMe loopback device support, which can be useful
+	  to test NVMe host and target side features.
+
+	  If unsure, say N.
+
+config NVME_TARGET_RDMA
+	tristate "NVMe over Fabrics RDMA target support"
+	depends on INFINIBAND && INFINIBAND_ADDR_TRANS
+	depends on NVME_TARGET
+	select SGL_ALLOC
+	help
+	  This enables the NVMe RDMA target support, which allows exporting NVMe
+	  devices over RDMA.
+
+	  If unsure, say N.
+
+config NVME_TARGET_FC
+	tristate "NVMe over Fabrics FC target driver"
+	depends on NVME_TARGET
+	depends on HAS_DMA
+	select SGL_ALLOC
+	help
+	  This enables the NVMe FC target support, which allows exporting NVMe
+	  devices over FC.
+
+	  If unsure, say N.
+
+config NVME_TARGET_FCLOOP
+	tristate "NVMe over Fabrics FC Transport Loopback Test driver"
+	depends on NVME_TARGET
+	select NVME_FABRICS
+	select SG_POOL
+	depends on NVME_FC
+	depends on NVME_TARGET_FC
+	help
+	  This enables the NVMe FC loopback test support, which can be useful
+	  to test NVMe-FC transport interfaces.
+
+	  If unsure, say N.
+
+config NVME_TARGET_TCP
+	tristate "NVMe over Fabrics TCP target support"
+	depends on INET
+	depends on NVME_TARGET
+	help
+	  This enables the NVMe TCP target support, which allows exporting NVMe
+	  devices over TCP.
+
+	  If unsure, say N.
+
+config NVME_TARGET_TCP_TLS
+	bool "NVMe over Fabrics TCP target TLS encryption support"
+	depends on NVME_TARGET_TCP
+	select NET_HANDSHAKE
+	select TLS
+	help
+	  Enables TLS encryption for the NVMe TCP target using the netlink handshake API.
+
+	  The TLS handshake daemon is available at
+	  https://github.com/oracle/ktls-utils.
+
+	  If unsure, say N.
+
+config NVME_TARGET_AUTH
+	bool "NVMe over Fabrics In-band Authentication in target side"
+	depends on NVME_TARGET
+	select NVME_AUTH
+	help
+	  This enables support for NVMe over Fabrics In-band Authentication in
+	  target side.
+
+	  If unsure, say N.
+
+config NVME_TARGET_AUTH_DEBUG
+	bool "NVMe over Fabrics In-band Authentication debug messages"
+	depends on NVME_TARGET_AUTH
+	help
+	  This enables additional debug messages including the generated
+	  DH-HMAC-CHAP secrets to help debugging authentication failures.
+
+	  If unsure, say N.
+
+config NVME_TARGET_PCI_EPF
+	tristate "NVMe PCI Endpoint Function target support"
+	depends on NVME_TARGET && PCI_ENDPOINT
+	depends on NVME_CORE=y || NVME_CORE=NVME_TARGET
+	help
+	  This enables the NVMe PCI Endpoint Function target driver support,
+	  which allows creating a NVMe PCI controller using an endpoint mode
+	  capable PCI controller.
+
+	  If unsure, say N.