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, 226 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/drd.h b/drivers/usb/cdns3/drd.h
new file mode 100644
index 000000000..1e2aee14d
--- /dev/null
+++ b/drivers/usb/cdns3/drd.h
@@ -0,0 +1,226 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Cadence USB3 and USBSSP DRD header file.
+ *
+ * Copyright (C) 2018-2020 Cadence.
+ *
+ * Author: Pawel Laszczak <pawell@cadence.com>
+ */
+#ifndef __LINUX_CDNS3_DRD
+#define __LINUX_CDNS3_DRD
+
+#include <linux/usb/otg.h>
+#include "core.h"
+
+/*  DRD register interface for version v1 of cdns3 driver. */
+struct cdns3_otg_regs {
+	__le32 did;
+	__le32 rid;
+	__le32 capabilities;
+	__le32 reserved1;
+	__le32 cmd;
+	__le32 sts;
+	__le32 state;
+	__le32 reserved2;
+	__le32 ien;
+	__le32 ivect;
+	__le32 refclk;
+	__le32 tmr;
+	__le32 reserved3[4];
+	__le32 simulate;
+	__le32 override;
+	__le32 susp_ctrl;
+	__le32 phyrst_cfg;
+	__le32 anasts;
+	__le32 adp_ramp_time;
+	__le32 ctrl1;
+	__le32 ctrl2;
+};
+
+/*  DRD register interface for version v0 of cdns3 driver. */
+struct cdns3_otg_legacy_regs {
+	__le32 cmd;
+	__le32 sts;
+	__le32 state;
+	__le32 refclk;
+	__le32 ien;
+	__le32 ivect;
+	__le32 reserved1[3];
+	__le32 tmr;
+	__le32 reserved2[2];
+	__le32 version;
+	__le32 capabilities;
+	__le32 reserved3[2];
+	__le32 simulate;
+	__le32 reserved4[5];
+	__le32 ctrl1;
+};
+
+/* DRD register interface for cdnsp driver */
+struct cdnsp_otg_regs {
+	__le32 did;
+	__le32 rid;
+	__le32 cfgs1;
+	__le32 cfgs2;
+	__le32 cmd;
+	__le32 sts;
+	__le32 state;
+	__le32 ien;
+	__le32 ivect;
+	__le32 tmr;
+	__le32 simulate;
+	__le32 adpbc_sts;
+	__le32 adp_ramp_time;
+	__le32 adpbc_ctrl1;
+	__le32 adpbc_ctrl2;
+	__le32 override;
+	__le32 vbusvalid_dbnc_cfg;
+	__le32 sessvalid_dbnc_cfg;
+	__le32 susp_timing_ctrl;
+};
+
+/* CDNSP driver supports 0x000403xx Cadence USB controller family. */
+#define OTG_CDNSP_CHECK_DID(did) (((did) & GENMASK(31, 8)) == 0x00040300)
+
+/* CDNS3 driver supports 0x000402xx Cadence USB controller family. */
+#define OTG_CDNS3_CHECK_DID(did) (((did) & GENMASK(31, 8)) == 0x00040200)
+
+/*
+ * Common registers interface for both CDNS3 and CDNSP version of DRD.
+ */
+struct cdns_otg_common_regs {
+	__le32 cmd;
+	__le32 sts;
+	__le32 state;
+};
+
+/*
+ * Interrupt related registers. This registers are mapped in different
+ * location for CDNSP controller.
+ */
+struct cdns_otg_irq_regs {
+	__le32 ien;
+	__le32 ivect;
+};
+
+/* CDNS_RID - bitmasks */
+#define CDNS_RID(p)			((p) & GENMASK(15, 0))
+
+/* CDNS_VID - bitmasks */
+#define CDNS_DID(p)			((p) & GENMASK(31, 0))
+
+/* OTGCMD - bitmasks */
+/* "Request the bus for Device mode. */
+#define OTGCMD_DEV_BUS_REQ		BIT(0)
+/* Request the bus for Host mode */
+#define OTGCMD_HOST_BUS_REQ		BIT(1)
+/* Enable OTG mode. */
+#define OTGCMD_OTG_EN			BIT(2)
+/* Disable OTG mode */
+#define OTGCMD_OTG_DIS			BIT(3)
+/*"Configure OTG as A-Device. */
+#define OTGCMD_A_DEV_EN			BIT(4)
+/*"Configure OTG as A-Device. */
+#define OTGCMD_A_DEV_DIS		BIT(5)
+/* Drop the bus for Device mod	e. */
+#define OTGCMD_DEV_BUS_DROP		BIT(8)
+/* Drop the bus for Host mode*/
+#define OTGCMD_HOST_BUS_DROP		BIT(9)
+/* Power Down USBSS-DEV - only for CDNS3.*/
+#define OTGCMD_DEV_POWER_OFF		BIT(11)
+/* Power Down CDNSXHCI - only for CDNS3. */
+#define OTGCMD_HOST_POWER_OFF		BIT(12)
+
+/* OTGIEN - bitmasks */
+/* ID change interrupt enable */
+#define OTGIEN_ID_CHANGE_INT		BIT(0)
+/* Vbusvalid fall detected interrupt enable.*/
+#define OTGIEN_VBUSVALID_RISE_INT	BIT(4)
+/* Vbusvalid fall detected interrupt enable */
+#define OTGIEN_VBUSVALID_FALL_INT	BIT(5)
+
+/* OTGSTS - bitmasks */
+/*
+ * Current value of the ID pin. It is only valid when idpullup in
+ *  OTGCTRL1_TYPE register is set to '1'.
+ */
+#define OTGSTS_ID_VALUE			BIT(0)
+/* Current value of the vbus_valid */
+#define OTGSTS_VBUS_VALID		BIT(1)
+/* Current value of the b_sess_vld */
+#define OTGSTS_SESSION_VALID		BIT(2)
+/*Device mode is active*/
+#define OTGSTS_DEV_ACTIVE		BIT(3)
+/* Host mode is active. */
+#define OTGSTS_HOST_ACTIVE		BIT(4)
+/* OTG Controller not ready. */
+#define OTGSTS_OTG_NRDY_MASK		BIT(11)
+#define OTGSTS_OTG_NRDY(p)		((p) & OTGSTS_OTG_NRDY_MASK)
+/*
+ * Value of the strap pins for:
+ * CDNS3:
+ * 000 - no default configuration
+ * 010 - Controller initiall configured as Host
+ * 100 - Controller initially configured as Device
+ * CDNSP:
+ * 000 - No default configuration.
+ * 010 - Controller initiall configured as Host.
+ * 100 - Controller initially configured as Device.
+ */
+#define OTGSTS_STRAP(p)			(((p) & GENMASK(14, 12)) >> 12)
+#define OTGSTS_STRAP_NO_DEFAULT_CFG	0x00
+#define OTGSTS_STRAP_HOST_OTG		0x01
+#define OTGSTS_STRAP_HOST		0x02
+#define OTGSTS_STRAP_GADGET		0x04
+#define OTGSTS_CDNSP_STRAP_HOST		0x01
+#define OTGSTS_CDNSP_STRAP_GADGET	0x02
+
+/* Host mode is turned on. */
+#define OTGSTS_CDNS3_XHCI_READY		BIT(26)
+#define OTGSTS_CDNSP_XHCI_READY		BIT(27)
+
+/* "Device mode is turned on .*/
+#define OTGSTS_CDNS3_DEV_READY		BIT(27)
+#define OTGSTS_CDNSP_DEV_READY		BIT(26)
+
+/* OTGSTATE- bitmasks */
+#define OTGSTATE_DEV_STATE_MASK		GENMASK(2, 0)
+#define OTGSTATE_HOST_STATE_MASK	GENMASK(5, 3)
+#define OTGSTATE_HOST_STATE_IDLE	0x0
+#define OTGSTATE_HOST_STATE_VBUS_FALL	0x7
+#define OTGSTATE_HOST_STATE(p)		(((p) & OTGSTATE_HOST_STATE_MASK) >> 3)
+
+/* OTGREFCLK - bitmasks */
+#define OTGREFCLK_STB_CLK_SWITCH_EN	BIT(31)
+
+/* SUPS_CTRL - bitmasks */
+#define SUSP_CTRL_SUSPEND_RESIDENCY_ENABLE	BIT(17)
+
+/* OVERRIDE - bitmasks */
+#define OVERRIDE_IDPULLUP		BIT(0)
+/* Only for CDNS3_CONTROLLER_V0 version */
+#define OVERRIDE_IDPULLUP_V0		BIT(24)
+/* Vbusvalid/Sesvalid override select. */
+#define OVERRIDE_SESS_VLD_SEL		BIT(10)
+
+/* PHYRST_CFG - bitmasks */
+#define PHYRST_CFG_PHYRST_A_ENABLE     BIT(0)
+
+#define CDNS3_ID_PERIPHERAL		1
+#define CDNS3_ID_HOST			0
+
+bool cdns_is_host(struct cdns *cdns);
+bool cdns_is_device(struct cdns *cdns);
+int cdns_get_id(struct cdns *cdns);
+int cdns_get_vbus(struct cdns *cdns);
+void cdns_clear_vbus(struct cdns *cdns);
+void cdns_set_vbus(struct cdns *cdns);
+int cdns_drd_init(struct cdns *cdns);
+int cdns_drd_exit(struct cdns *cdns);
+int cdns_drd_update_mode(struct cdns *cdns);
+int cdns_drd_gadget_on(struct cdns *cdns);
+void cdns_drd_gadget_off(struct cdns *cdns);
+int cdns_drd_host_on(struct cdns *cdns);
+void cdns_drd_host_off(struct cdns *cdns);
+bool cdns_power_is_lost(struct cdns *cdns);
+#endif /* __LINUX_CDNS3_DRD */