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, 125 insertions, 0 deletions

diff --git a/drivers/ata/pata_piccolo.c b/drivers/ata/pata_piccolo.c
new file mode 100644
index 000000000..beb53bd99
--- /dev/null
+++ b/drivers/ata/pata_piccolo.c
@@ -0,0 +1,125 @@
+/*
+ *  pata_piccolo.c - Toshiba Piccolo PATA/SATA controller driver.
+ *
+ *  This is basically an update to ata_generic.c to add Toshiba Piccolo support
+ *  then split out to keep ata_generic "clean".
+ *
+ *  Copyright 2005 Red Hat Inc, all rights reserved.
+ *
+ *  Elements from ide/pci/generic.c
+ *	    Copyright (C) 2001-2002	Andre Hedrick <andre@linux-ide.org>
+ *	    Portions (C) Copyright 2002  Red Hat Inc <alan@redhat.com>
+ *
+ *  May be copied or modified under the terms of the GNU General Public License
+ *
+ *  The timing data tables/programming info are courtesy of the NetBSD driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <scsi/scsi_host.h>
+#include <linux/libata.h>
+
+#define DRV_NAME "pata_piccolo"
+#define DRV_VERSION "0.0.1"
+
+
+
+static void tosh_set_piomode(struct ata_port *ap, struct ata_device *adev)
+{
+	static const u16 pio[6] = {	/* For reg 0x50 low word & E088 */
+		0x0566, 0x0433, 0x0311, 0x0201, 0x0200, 0x0100
+	};
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	u16 conf;
+	pci_read_config_word(pdev, 0x50, &conf);
+	conf &= 0xE088;
+	conf |= pio[adev->pio_mode - XFER_PIO_0];
+	pci_write_config_word(pdev, 0x50, conf);
+}
+
+static void tosh_set_dmamode(struct ata_port *ap, struct ata_device *adev)
+{
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	u32 conf;
+	pci_read_config_dword(pdev, 0x5C, &conf);
+	conf &= 0x78FFE088;	/* Keep the other bits */
+	if (adev->dma_mode >= XFER_UDMA_0) {
+		int udma = adev->dma_mode - XFER_UDMA_0;
+		conf |= 0x80000000;
+		conf |= (udma + 2) << 28;
+		conf |= (2 - udma) * 0x111;	/* spread into three nibbles */
+	} else {
+		static const u32 mwdma[4] = {
+			0x0655, 0x0200, 0x0200, 0x0100
+		};
+		conf |= mwdma[adev->dma_mode - XFER_MW_DMA_0];
+	}
+	pci_write_config_dword(pdev, 0x5C, conf);
+}
+
+
+static const struct scsi_host_template tosh_sht = {
+	ATA_BMDMA_SHT(DRV_NAME),
+};
+
+static struct ata_port_operations tosh_port_ops = {
+	.inherits	= &ata_bmdma_port_ops,
+	.cable_detect	= ata_cable_unknown,
+	.set_piomode	= tosh_set_piomode,
+	.set_dmamode	= tosh_set_dmamode
+};
+
+/**
+ *	ata_tosh_init_one		-	attach generic IDE
+ *	@dev: PCI device found
+ *	@id: match entry
+ *
+ *	Called each time a matching IDE interface is found. We check if the
+ *	interface is one we wish to claim and if so we perform any chip
+ *	specific hacks then let the ATA layer do the heavy lifting.
+ */
+
+static int ata_tosh_init_one(struct pci_dev *dev, const struct pci_device_id *id)
+{
+	static const struct ata_port_info info = {
+		.flags = ATA_FLAG_SLAVE_POSS,
+		.pio_mask = ATA_PIO5,
+		.mwdma_mask = ATA_MWDMA2,
+		.udma_mask = ATA_UDMA2,
+		.port_ops = &tosh_port_ops
+	};
+	const struct ata_port_info *ppi[] = { &info, &ata_dummy_port_info };
+	/* Just one port for the moment */
+	return ata_pci_bmdma_init_one(dev, ppi, &tosh_sht, NULL, 0);
+}
+
+static const struct pci_device_id ata_tosh[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_TOSHIBA,PCI_DEVICE_ID_TOSHIBA_PICCOLO_1), },
+	{ PCI_DEVICE(PCI_VENDOR_ID_TOSHIBA,PCI_DEVICE_ID_TOSHIBA_PICCOLO_2),  },
+	{ PCI_DEVICE(PCI_VENDOR_ID_TOSHIBA,PCI_DEVICE_ID_TOSHIBA_PICCOLO_3),  },
+	{ PCI_DEVICE(PCI_VENDOR_ID_TOSHIBA,PCI_DEVICE_ID_TOSHIBA_PICCOLO_5),  },
+	{ 0, },
+};
+
+static struct pci_driver ata_tosh_pci_driver = {
+	.name 		= DRV_NAME,
+	.id_table	= ata_tosh,
+	.probe 		= ata_tosh_init_one,
+	.remove		= ata_pci_remove_one,
+#ifdef CONFIG_PM_SLEEP
+	.suspend	= ata_pci_device_suspend,
+	.resume		= ata_pci_device_resume,
+#endif
+};
+
+module_pci_driver(ata_tosh_pci_driver);
+
+MODULE_AUTHOR("Alan Cox");
+MODULE_DESCRIPTION("Low level driver for Toshiba Piccolo ATA");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(pci, ata_tosh);
+MODULE_VERSION(DRV_VERSION);