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, 613 insertions, 0 deletions

diff --git a/drivers/scsi/sun_esp.c b/drivers/scsi/sun_esp.c
new file mode 100644
index 000000000..aa430501f
--- /dev/null
+++ b/drivers/scsi/sun_esp.c
@@ -0,0 +1,613 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* sun_esp.c: ESP front-end for Sparc SBUS systems.
+ *
+ * Copyright (C) 2007, 2008 David S. Miller (davem@davemloft.net)
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/dma-mapping.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/gfp.h>
+
+#include <asm/irq.h>
+#include <asm/io.h>
+#include <asm/dma.h>
+
+#include <scsi/scsi_host.h>
+
+#include "esp_scsi.h"
+
+#define DRV_MODULE_NAME		"sun_esp"
+#define PFX DRV_MODULE_NAME	": "
+#define DRV_VERSION		"1.100"
+#define DRV_MODULE_RELDATE	"August 27, 2008"
+
+#define dma_read32(REG) \
+	sbus_readl(esp->dma_regs + (REG))
+#define dma_write32(VAL, REG) \
+	sbus_writel((VAL), esp->dma_regs + (REG))
+
+/* DVMA chip revisions */
+enum dvma_rev {
+	dvmarev0,
+	dvmaesc1,
+	dvmarev1,
+	dvmarev2,
+	dvmarev3,
+	dvmarevplus,
+	dvmahme
+};
+
+static int esp_sbus_setup_dma(struct esp *esp, struct platform_device *dma_of)
+{
+	esp->dma = dma_of;
+
+	esp->dma_regs = of_ioremap(&dma_of->resource[0], 0,
+				   resource_size(&dma_of->resource[0]),
+				   "espdma");
+	if (!esp->dma_regs)
+		return -ENOMEM;
+
+	switch (dma_read32(DMA_CSR) & DMA_DEVICE_ID) {
+	case DMA_VERS0:
+		esp->dmarev = dvmarev0;
+		break;
+	case DMA_ESCV1:
+		esp->dmarev = dvmaesc1;
+		break;
+	case DMA_VERS1:
+		esp->dmarev = dvmarev1;
+		break;
+	case DMA_VERS2:
+		esp->dmarev = dvmarev2;
+		break;
+	case DMA_VERHME:
+		esp->dmarev = dvmahme;
+		break;
+	case DMA_VERSPLUS:
+		esp->dmarev = dvmarevplus;
+		break;
+	}
+
+	return 0;
+
+}
+
+static int esp_sbus_map_regs(struct esp *esp, int hme)
+{
+	struct platform_device *op = to_platform_device(esp->dev);
+	struct resource *res;
+
+	/* On HME, two reg sets exist, first is DVMA,
+	 * second is ESP registers.
+	 */
+	if (hme)
+		res = &op->resource[1];
+	else
+		res = &op->resource[0];
+
+	esp->regs = of_ioremap(res, 0, SBUS_ESP_REG_SIZE, "ESP");
+	if (!esp->regs)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int esp_sbus_map_command_block(struct esp *esp)
+{
+	esp->command_block = dma_alloc_coherent(esp->dev, 16,
+						&esp->command_block_dma,
+						GFP_KERNEL);
+	if (!esp->command_block)
+		return -ENOMEM;
+	return 0;
+}
+
+static int esp_sbus_register_irq(struct esp *esp)
+{
+	struct Scsi_Host *host = esp->host;
+	struct platform_device *op = to_platform_device(esp->dev);
+
+	host->irq = op->archdata.irqs[0];
+	return request_irq(host->irq, scsi_esp_intr, IRQF_SHARED, "ESP", esp);
+}
+
+static void esp_get_scsi_id(struct esp *esp, struct platform_device *espdma)
+{
+	struct platform_device *op = to_platform_device(esp->dev);
+	struct device_node *dp;
+
+	dp = op->dev.of_node;
+	esp->scsi_id = of_getintprop_default(dp, "initiator-id", 0xff);
+	if (esp->scsi_id != 0xff)
+		goto done;
+
+	esp->scsi_id = of_getintprop_default(dp, "scsi-initiator-id", 0xff);
+	if (esp->scsi_id != 0xff)
+		goto done;
+
+	esp->scsi_id = of_getintprop_default(espdma->dev.of_node,
+					     "scsi-initiator-id", 7);
+
+done:
+	esp->host->this_id = esp->scsi_id;
+	esp->scsi_id_mask = (1 << esp->scsi_id);
+}
+
+static void esp_get_differential(struct esp *esp)
+{
+	struct platform_device *op = to_platform_device(esp->dev);
+	struct device_node *dp;
+
+	dp = op->dev.of_node;
+	if (of_property_read_bool(dp, "differential"))
+		esp->flags |= ESP_FLAG_DIFFERENTIAL;
+	else
+		esp->flags &= ~ESP_FLAG_DIFFERENTIAL;
+}
+
+static void esp_get_clock_params(struct esp *esp)
+{
+	struct platform_device *op = to_platform_device(esp->dev);
+	struct device_node *bus_dp, *dp;
+	int fmhz;
+
+	dp = op->dev.of_node;
+	bus_dp = dp->parent;
+
+	fmhz = of_getintprop_default(dp, "clock-frequency", 0);
+	if (fmhz == 0)
+		fmhz = of_getintprop_default(bus_dp, "clock-frequency", 0);
+
+	esp->cfreq = fmhz;
+}
+
+static void esp_get_bursts(struct esp *esp, struct platform_device *dma_of)
+{
+	struct device_node *dma_dp = dma_of->dev.of_node;
+	struct platform_device *op = to_platform_device(esp->dev);
+	struct device_node *dp;
+	u8 bursts, val;
+
+	dp = op->dev.of_node;
+	bursts = of_getintprop_default(dp, "burst-sizes", 0xff);
+	val = of_getintprop_default(dma_dp, "burst-sizes", 0xff);
+	if (val != 0xff)
+		bursts &= val;
+
+	val = of_getintprop_default(dma_dp->parent, "burst-sizes", 0xff);
+	if (val != 0xff)
+		bursts &= val;
+
+	if (bursts == 0xff ||
+	    (bursts & DMA_BURST16) == 0 ||
+	    (bursts & DMA_BURST32) == 0)
+		bursts = (DMA_BURST32 - 1);
+
+	esp->bursts = bursts;
+}
+
+static void esp_sbus_get_props(struct esp *esp, struct platform_device *espdma)
+{
+	esp_get_scsi_id(esp, espdma);
+	esp_get_differential(esp);
+	esp_get_clock_params(esp);
+	esp_get_bursts(esp, espdma);
+}
+
+static void sbus_esp_write8(struct esp *esp, u8 val, unsigned long reg)
+{
+	sbus_writeb(val, esp->regs + (reg * 4UL));
+}
+
+static u8 sbus_esp_read8(struct esp *esp, unsigned long reg)
+{
+	return sbus_readb(esp->regs + (reg * 4UL));
+}
+
+static int sbus_esp_irq_pending(struct esp *esp)
+{
+	if (dma_read32(DMA_CSR) & (DMA_HNDL_INTR | DMA_HNDL_ERROR))
+		return 1;
+	return 0;
+}
+
+static void sbus_esp_reset_dma(struct esp *esp)
+{
+	int can_do_burst16, can_do_burst32, can_do_burst64;
+	int can_do_sbus64, lim;
+	struct platform_device *op = to_platform_device(esp->dev);
+	u32 val;
+
+	can_do_burst16 = (esp->bursts & DMA_BURST16) != 0;
+	can_do_burst32 = (esp->bursts & DMA_BURST32) != 0;
+	can_do_burst64 = 0;
+	can_do_sbus64 = 0;
+	if (sbus_can_dma_64bit())
+		can_do_sbus64 = 1;
+	if (sbus_can_burst64())
+		can_do_burst64 = (esp->bursts & DMA_BURST64) != 0;
+
+	/* Put the DVMA into a known state. */
+	if (esp->dmarev != dvmahme) {
+		val = dma_read32(DMA_CSR);
+		dma_write32(val | DMA_RST_SCSI, DMA_CSR);
+		dma_write32(val & ~DMA_RST_SCSI, DMA_CSR);
+	}
+	switch (esp->dmarev) {
+	case dvmahme:
+		dma_write32(DMA_RESET_FAS366, DMA_CSR);
+		dma_write32(DMA_RST_SCSI, DMA_CSR);
+
+		esp->prev_hme_dmacsr = (DMA_PARITY_OFF | DMA_2CLKS |
+					DMA_SCSI_DISAB | DMA_INT_ENAB);
+
+		esp->prev_hme_dmacsr &= ~(DMA_ENABLE | DMA_ST_WRITE |
+					  DMA_BRST_SZ);
+
+		if (can_do_burst64)
+			esp->prev_hme_dmacsr |= DMA_BRST64;
+		else if (can_do_burst32)
+			esp->prev_hme_dmacsr |= DMA_BRST32;
+
+		if (can_do_sbus64) {
+			esp->prev_hme_dmacsr |= DMA_SCSI_SBUS64;
+			sbus_set_sbus64(&op->dev, esp->bursts);
+		}
+
+		lim = 1000;
+		while (dma_read32(DMA_CSR) & DMA_PEND_READ) {
+			if (--lim == 0) {
+				printk(KERN_ALERT PFX "esp%d: DMA_PEND_READ "
+				       "will not clear!\n",
+				       esp->host->unique_id);
+				break;
+			}
+			udelay(1);
+		}
+
+		dma_write32(0, DMA_CSR);
+		dma_write32(esp->prev_hme_dmacsr, DMA_CSR);
+
+		dma_write32(0, DMA_ADDR);
+		break;
+
+	case dvmarev2:
+		if (esp->rev != ESP100) {
+			val = dma_read32(DMA_CSR);
+			dma_write32(val | DMA_3CLKS, DMA_CSR);
+		}
+		break;
+
+	case dvmarev3:
+		val = dma_read32(DMA_CSR);
+		val &= ~DMA_3CLKS;
+		val |= DMA_2CLKS;
+		if (can_do_burst32) {
+			val &= ~DMA_BRST_SZ;
+			val |= DMA_BRST32;
+		}
+		dma_write32(val, DMA_CSR);
+		break;
+
+	case dvmaesc1:
+		val = dma_read32(DMA_CSR);
+		val |= DMA_ADD_ENABLE;
+		val &= ~DMA_BCNT_ENAB;
+		if (!can_do_burst32 && can_do_burst16) {
+			val |= DMA_ESC_BURST;
+		} else {
+			val &= ~(DMA_ESC_BURST);
+		}
+		dma_write32(val, DMA_CSR);
+		break;
+
+	default:
+		break;
+	}
+
+	/* Enable interrupts.  */
+	val = dma_read32(DMA_CSR);
+	dma_write32(val | DMA_INT_ENAB, DMA_CSR);
+}
+
+static void sbus_esp_dma_drain(struct esp *esp)
+{
+	u32 csr;
+	int lim;
+
+	if (esp->dmarev == dvmahme)
+		return;
+
+	csr = dma_read32(DMA_CSR);
+	if (!(csr & DMA_FIFO_ISDRAIN))
+		return;
+
+	if (esp->dmarev != dvmarev3 && esp->dmarev != dvmaesc1)
+		dma_write32(csr | DMA_FIFO_STDRAIN, DMA_CSR);
+
+	lim = 1000;
+	while (dma_read32(DMA_CSR) & DMA_FIFO_ISDRAIN) {
+		if (--lim == 0) {
+			printk(KERN_ALERT PFX "esp%d: DMA will not drain!\n",
+			       esp->host->unique_id);
+			break;
+		}
+		udelay(1);
+	}
+}
+
+static void sbus_esp_dma_invalidate(struct esp *esp)
+{
+	if (esp->dmarev == dvmahme) {
+		dma_write32(DMA_RST_SCSI, DMA_CSR);
+
+		esp->prev_hme_dmacsr = ((esp->prev_hme_dmacsr |
+					 (DMA_PARITY_OFF | DMA_2CLKS |
+					  DMA_SCSI_DISAB | DMA_INT_ENAB)) &
+					~(DMA_ST_WRITE | DMA_ENABLE));
+
+		dma_write32(0, DMA_CSR);
+		dma_write32(esp->prev_hme_dmacsr, DMA_CSR);
+
+		/* This is necessary to avoid having the SCSI channel
+		 * engine lock up on us.
+		 */
+		dma_write32(0, DMA_ADDR);
+	} else {
+		u32 val;
+		int lim;
+
+		lim = 1000;
+		while ((val = dma_read32(DMA_CSR)) & DMA_PEND_READ) {
+			if (--lim == 0) {
+				printk(KERN_ALERT PFX "esp%d: DMA will not "
+				       "invalidate!\n", esp->host->unique_id);
+				break;
+			}
+			udelay(1);
+		}
+
+		val &= ~(DMA_ENABLE | DMA_ST_WRITE | DMA_BCNT_ENAB);
+		val |= DMA_FIFO_INV;
+		dma_write32(val, DMA_CSR);
+		val &= ~DMA_FIFO_INV;
+		dma_write32(val, DMA_CSR);
+	}
+}
+
+static void sbus_esp_send_dma_cmd(struct esp *esp, u32 addr, u32 esp_count,
+				  u32 dma_count, int write, u8 cmd)
+{
+	u32 csr;
+
+	BUG_ON(!(cmd & ESP_CMD_DMA));
+
+	sbus_esp_write8(esp, (esp_count >> 0) & 0xff, ESP_TCLOW);
+	sbus_esp_write8(esp, (esp_count >> 8) & 0xff, ESP_TCMED);
+	if (esp->rev == FASHME) {
+		sbus_esp_write8(esp, (esp_count >> 16) & 0xff, FAS_RLO);
+		sbus_esp_write8(esp, 0, FAS_RHI);
+
+		scsi_esp_cmd(esp, cmd);
+
+		csr = esp->prev_hme_dmacsr;
+		csr |= DMA_SCSI_DISAB | DMA_ENABLE;
+		if (write)
+			csr |= DMA_ST_WRITE;
+		else
+			csr &= ~DMA_ST_WRITE;
+		esp->prev_hme_dmacsr = csr;
+
+		dma_write32(dma_count, DMA_COUNT);
+		dma_write32(addr, DMA_ADDR);
+		dma_write32(csr, DMA_CSR);
+	} else {
+		csr = dma_read32(DMA_CSR);
+		csr |= DMA_ENABLE;
+		if (write)
+			csr |= DMA_ST_WRITE;
+		else
+			csr &= ~DMA_ST_WRITE;
+		dma_write32(csr, DMA_CSR);
+		if (esp->dmarev == dvmaesc1) {
+			u32 end = PAGE_ALIGN(addr + dma_count + 16U);
+			dma_write32(end - addr, DMA_COUNT);
+		}
+		dma_write32(addr, DMA_ADDR);
+
+		scsi_esp_cmd(esp, cmd);
+	}
+
+}
+
+static int sbus_esp_dma_error(struct esp *esp)
+{
+	u32 csr = dma_read32(DMA_CSR);
+
+	if (csr & DMA_HNDL_ERROR)
+		return 1;
+
+	return 0;
+}
+
+static const struct esp_driver_ops sbus_esp_ops = {
+	.esp_write8	=	sbus_esp_write8,
+	.esp_read8	=	sbus_esp_read8,
+	.irq_pending	=	sbus_esp_irq_pending,
+	.reset_dma	=	sbus_esp_reset_dma,
+	.dma_drain	=	sbus_esp_dma_drain,
+	.dma_invalidate	=	sbus_esp_dma_invalidate,
+	.send_dma_cmd	=	sbus_esp_send_dma_cmd,
+	.dma_error	=	sbus_esp_dma_error,
+};
+
+static int esp_sbus_probe_one(struct platform_device *op,
+			      struct platform_device *espdma, int hme)
+{
+	const struct scsi_host_template *tpnt = &scsi_esp_template;
+	struct Scsi_Host *host;
+	struct esp *esp;
+	int err;
+
+	host = scsi_host_alloc(tpnt, sizeof(struct esp));
+
+	err = -ENOMEM;
+	if (!host)
+		goto fail;
+
+	host->max_id = (hme ? 16 : 8);
+	esp = shost_priv(host);
+
+	esp->host = host;
+	esp->dev = &op->dev;
+	esp->ops = &sbus_esp_ops;
+
+	if (hme)
+		esp->flags |= ESP_FLAG_WIDE_CAPABLE;
+
+	err = esp_sbus_setup_dma(esp, espdma);
+	if (err < 0)
+		goto fail_unlink;
+
+	err = esp_sbus_map_regs(esp, hme);
+	if (err < 0)
+		goto fail_unlink;
+
+	err = esp_sbus_map_command_block(esp);
+	if (err < 0)
+		goto fail_unmap_regs;
+
+	err = esp_sbus_register_irq(esp);
+	if (err < 0)
+		goto fail_unmap_command_block;
+
+	esp_sbus_get_props(esp, espdma);
+
+	/* Before we try to touch the ESP chip, ESC1 dma can
+	 * come up with the reset bit set, so make sure that
+	 * is clear first.
+	 */
+	if (esp->dmarev == dvmaesc1) {
+		u32 val = dma_read32(DMA_CSR);
+
+		dma_write32(val & ~DMA_RST_SCSI, DMA_CSR);
+	}
+
+	dev_set_drvdata(&op->dev, esp);
+
+	err = scsi_esp_register(esp);
+	if (err)
+		goto fail_free_irq;
+
+	return 0;
+
+fail_free_irq:
+	free_irq(host->irq, esp);
+fail_unmap_command_block:
+	dma_free_coherent(&op->dev, 16,
+			  esp->command_block,
+			  esp->command_block_dma);
+fail_unmap_regs:
+	of_iounmap(&op->resource[(hme ? 1 : 0)], esp->regs, SBUS_ESP_REG_SIZE);
+fail_unlink:
+	scsi_host_put(host);
+fail:
+	return err;
+}
+
+static int esp_sbus_probe(struct platform_device *op)
+{
+	struct device_node *dma_node = NULL;
+	struct device_node *dp = op->dev.of_node;
+	struct platform_device *dma_of = NULL;
+	int hme = 0;
+	int ret;
+
+	if (of_node_name_eq(dp->parent, "espdma") ||
+	    of_node_name_eq(dp->parent, "dma"))
+		dma_node = dp->parent;
+	else if (of_node_name_eq(dp, "SUNW,fas")) {
+		dma_node = op->dev.of_node;
+		hme = 1;
+	}
+	if (dma_node)
+		dma_of = of_find_device_by_node(dma_node);
+	if (!dma_of)
+		return -ENODEV;
+
+	ret = esp_sbus_probe_one(op, dma_of, hme);
+	if (ret)
+		put_device(&dma_of->dev);
+
+	return ret;
+}
+
+static void esp_sbus_remove(struct platform_device *op)
+{
+	struct esp *esp = dev_get_drvdata(&op->dev);
+	struct platform_device *dma_of = esp->dma;
+	unsigned int irq = esp->host->irq;
+	bool is_hme;
+	u32 val;
+
+	scsi_esp_unregister(esp);
+
+	/* Disable interrupts.  */
+	val = dma_read32(DMA_CSR);
+	dma_write32(val & ~DMA_INT_ENAB, DMA_CSR);
+
+	free_irq(irq, esp);
+
+	is_hme = (esp->dmarev == dvmahme);
+
+	dma_free_coherent(&op->dev, 16,
+			  esp->command_block,
+			  esp->command_block_dma);
+	of_iounmap(&op->resource[(is_hme ? 1 : 0)], esp->regs,
+		   SBUS_ESP_REG_SIZE);
+	of_iounmap(&dma_of->resource[0], esp->dma_regs,
+		   resource_size(&dma_of->resource[0]));
+
+	scsi_host_put(esp->host);
+
+	dev_set_drvdata(&op->dev, NULL);
+
+	put_device(&dma_of->dev);
+}
+
+static const struct of_device_id esp_match[] = {
+	{
+		.name = "SUNW,esp",
+	},
+	{
+		.name = "SUNW,fas",
+	},
+	{
+		.name = "esp",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, esp_match);
+
+static struct platform_driver esp_sbus_driver = {
+	.driver = {
+		.name = "esp",
+		.of_match_table = esp_match,
+	},
+	.probe		= esp_sbus_probe,
+	.remove		= esp_sbus_remove,
+};
+module_platform_driver(esp_sbus_driver);
+
+MODULE_DESCRIPTION("Sun ESP SCSI driver");
+MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);