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, 45 insertions, 0 deletions

diff --git a/drivers/misc/cardreader/rts5260.h b/drivers/misc/cardreader/rts5260.h
new file mode 100644
index 000000000..53a1411c8
--- /dev/null
+++ b/drivers/misc/cardreader/rts5260.h
@@ -0,0 +1,45 @@
+#ifndef __RTS5260_H__
+#define __RTS5260_H__
+
+#define RTS5260_DVCC_CTRL		0xFF73
+#define RTS5260_DVCC_OCP_EN		(0x01 << 7)
+#define RTS5260_DVCC_OCP_THD_MASK	(0x07 << 4)
+#define RTS5260_DVCC_POWERON		(0x01 << 3)
+#define RTS5260_DVCC_OCP_CL_EN		(0x01 << 2)
+
+#define RTS5260_DVIO_CTRL		0xFF75
+#define RTS5260_DVIO_OCP_EN		(0x01 << 7)
+#define RTS5260_DVIO_OCP_THD_MASK	(0x07 << 4)
+#define RTS5260_DVIO_POWERON		(0x01 << 3)
+#define RTS5260_DVIO_OCP_CL_EN		(0x01 << 2)
+
+#define RTS5260_DV331812_CFG		0xFF71
+#define RTS5260_DV331812_OCP_EN		(0x01 << 7)
+#define RTS5260_DV331812_OCP_THD_MASK	(0x07 << 4)
+#define RTS5260_DV331812_POWERON	(0x01 << 3)
+#define RTS5260_DV331812_SEL		(0x01 << 2)
+#define RTS5260_DV331812_VDD1		(0x01 << 2)
+#define RTS5260_DV331812_VDD2		(0x00 << 2)
+
+#define RTS5260_DV331812_OCP_THD_120	(0x00 << 4)
+#define RTS5260_DV331812_OCP_THD_140	(0x01 << 4)
+#define RTS5260_DV331812_OCP_THD_160	(0x02 << 4)
+#define RTS5260_DV331812_OCP_THD_180	(0x03 << 4)
+#define RTS5260_DV331812_OCP_THD_210	(0x04 << 4)
+#define RTS5260_DV331812_OCP_THD_240	(0x05 << 4)
+#define RTS5260_DV331812_OCP_THD_270	(0x06 << 4)
+#define RTS5260_DV331812_OCP_THD_300	(0x07 << 4)
+
+#define RTS5260_DVIO_OCP_THD_250	(0x00 << 4)
+#define RTS5260_DVIO_OCP_THD_300	(0x01 << 4)
+#define RTS5260_DVIO_OCP_THD_350	(0x02 << 4)
+#define RTS5260_DVIO_OCP_THD_400	(0x03 << 4)
+#define RTS5260_DVIO_OCP_THD_450	(0x04 << 4)
+#define RTS5260_DVIO_OCP_THD_500	(0x05 << 4)
+#define RTS5260_DVIO_OCP_THD_550	(0x06 << 4)
+#define RTS5260_DVIO_OCP_THD_600	(0x07 << 4)
+
+#define RTS5260_DVCC_OCP_THD_550	(0x00 << 4)
+#define RTS5260_DVCC_OCP_THD_970	(0x05 << 4)
+
+#endif