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, 272 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
new file mode 100644
index 000000000..2652fecbf
--- /dev/null
+++ b/drivers/scsi/scsi_pm.c
@@ -0,0 +1,272 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *	scsi_pm.c	Copyright (C) 2010 Alan Stern
+ *
+ *	SCSI dynamic Power Management
+ *		Initial version: Alan Stern <stern@rowland.harvard.edu>
+ */
+
+#include <linux/pm_runtime.h>
+#include <linux/export.h>
+#include <linux/blk-pm.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_host.h>
+
+#include "scsi_priv.h"
+
+#ifdef CONFIG_PM_SLEEP
+
+static int do_scsi_suspend(struct device *dev, const struct dev_pm_ops *pm)
+{
+	return pm && pm->suspend ? pm->suspend(dev) : 0;
+}
+
+static int do_scsi_freeze(struct device *dev, const struct dev_pm_ops *pm)
+{
+	return pm && pm->freeze ? pm->freeze(dev) : 0;
+}
+
+static int do_scsi_poweroff(struct device *dev, const struct dev_pm_ops *pm)
+{
+	return pm && pm->poweroff ? pm->poweroff(dev) : 0;
+}
+
+static int do_scsi_resume(struct device *dev, const struct dev_pm_ops *pm)
+{
+	return pm && pm->resume ? pm->resume(dev) : 0;
+}
+
+static int do_scsi_thaw(struct device *dev, const struct dev_pm_ops *pm)
+{
+	return pm && pm->thaw ? pm->thaw(dev) : 0;
+}
+
+static int do_scsi_restore(struct device *dev, const struct dev_pm_ops *pm)
+{
+	return pm && pm->restore ? pm->restore(dev) : 0;
+}
+
+static int scsi_dev_type_suspend(struct device *dev,
+		int (*cb)(struct device *, const struct dev_pm_ops *))
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	int err;
+
+	err = scsi_device_quiesce(to_scsi_device(dev));
+	if (err == 0) {
+		err = cb(dev, pm);
+		if (err)
+			scsi_device_resume(to_scsi_device(dev));
+	}
+	dev_dbg(dev, "scsi suspend: %d\n", err);
+	return err;
+}
+
+static int
+scsi_bus_suspend_common(struct device *dev,
+		int (*cb)(struct device *, const struct dev_pm_ops *))
+{
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	return scsi_dev_type_suspend(dev, cb);
+}
+
+static int scsi_bus_resume_common(struct device *dev,
+		int (*cb)(struct device *, const struct dev_pm_ops *))
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	int err;
+
+	if (!scsi_is_sdev_device(dev))
+		return 0;
+
+	err = cb(dev, pm);
+	scsi_device_resume(to_scsi_device(dev));
+	dev_dbg(dev, "scsi resume: %d\n", err);
+
+	return err;
+}
+
+static int scsi_bus_prepare(struct device *dev)
+{
+	if (scsi_is_host_device(dev)) {
+		/* Wait until async scanning is finished */
+		scsi_complete_async_scans();
+	}
+	return 0;
+}
+
+static int scsi_bus_suspend(struct device *dev)
+{
+	return scsi_bus_suspend_common(dev, do_scsi_suspend);
+}
+
+static int scsi_bus_resume(struct device *dev)
+{
+	return scsi_bus_resume_common(dev, do_scsi_resume);
+}
+
+static int scsi_bus_freeze(struct device *dev)
+{
+	return scsi_bus_suspend_common(dev, do_scsi_freeze);
+}
+
+static int scsi_bus_thaw(struct device *dev)
+{
+	return scsi_bus_resume_common(dev, do_scsi_thaw);
+}
+
+static int scsi_bus_poweroff(struct device *dev)
+{
+	return scsi_bus_suspend_common(dev, do_scsi_poweroff);
+}
+
+static int scsi_bus_restore(struct device *dev)
+{
+	return scsi_bus_resume_common(dev, do_scsi_restore);
+}
+
+#else /* CONFIG_PM_SLEEP */
+
+#define scsi_bus_prepare		NULL
+#define scsi_bus_suspend		NULL
+#define scsi_bus_resume			NULL
+#define scsi_bus_freeze			NULL
+#define scsi_bus_thaw			NULL
+#define scsi_bus_poweroff		NULL
+#define scsi_bus_restore		NULL
+
+#endif /* CONFIG_PM_SLEEP */
+
+static int sdev_runtime_suspend(struct device *dev)
+{
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	struct scsi_device *sdev = to_scsi_device(dev);
+	int err = 0;
+
+	err = blk_pre_runtime_suspend(sdev->request_queue);
+	if (err)
+		return err;
+	if (pm && pm->runtime_suspend)
+		err = pm->runtime_suspend(dev);
+	blk_post_runtime_suspend(sdev->request_queue, err);
+
+	return err;
+}
+
+static int scsi_runtime_suspend(struct device *dev)
+{
+	int err = 0;
+
+	dev_dbg(dev, "scsi_runtime_suspend\n");
+	if (scsi_is_sdev_device(dev))
+		err = sdev_runtime_suspend(dev);
+
+	/* Insert hooks here for targets, hosts, and transport classes */
+
+	return err;
+}
+
+static int sdev_runtime_resume(struct device *dev)
+{
+	struct scsi_device *sdev = to_scsi_device(dev);
+	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
+	int err = 0;
+
+	blk_pre_runtime_resume(sdev->request_queue);
+	if (pm && pm->runtime_resume)
+		err = pm->runtime_resume(dev);
+	blk_post_runtime_resume(sdev->request_queue);
+
+	return err;
+}
+
+static int scsi_runtime_resume(struct device *dev)
+{
+	int err = 0;
+
+	dev_dbg(dev, "scsi_runtime_resume\n");
+	if (scsi_is_sdev_device(dev))
+		err = sdev_runtime_resume(dev);
+
+	/* Insert hooks here for targets, hosts, and transport classes */
+
+	return err;
+}
+
+static int scsi_runtime_idle(struct device *dev)
+{
+	dev_dbg(dev, "scsi_runtime_idle\n");
+
+	/* Insert hooks here for targets, hosts, and transport classes */
+
+	if (scsi_is_sdev_device(dev)) {
+		pm_runtime_autosuspend(dev);
+		return -EBUSY;
+	}
+
+	return 0;
+}
+
+int scsi_autopm_get_device(struct scsi_device *sdev)
+{
+	int	err;
+
+	err = pm_runtime_get_sync(&sdev->sdev_gendev);
+	if (err < 0 && err !=-EACCES)
+		pm_runtime_put_sync(&sdev->sdev_gendev);
+	else
+		err = 0;
+	return err;
+}
+EXPORT_SYMBOL_GPL(scsi_autopm_get_device);
+
+void scsi_autopm_put_device(struct scsi_device *sdev)
+{
+	pm_runtime_put_sync(&sdev->sdev_gendev);
+}
+EXPORT_SYMBOL_GPL(scsi_autopm_put_device);
+
+void scsi_autopm_get_target(struct scsi_target *starget)
+{
+	pm_runtime_get_sync(&starget->dev);
+}
+
+void scsi_autopm_put_target(struct scsi_target *starget)
+{
+	pm_runtime_put_sync(&starget->dev);
+}
+
+int scsi_autopm_get_host(struct Scsi_Host *shost)
+{
+	int	err;
+
+	err = pm_runtime_get_sync(&shost->shost_gendev);
+	if (err < 0 && err !=-EACCES)
+		pm_runtime_put_sync(&shost->shost_gendev);
+	else
+		err = 0;
+	return err;
+}
+
+void scsi_autopm_put_host(struct Scsi_Host *shost)
+{
+	pm_runtime_put_sync(&shost->shost_gendev);
+}
+
+const struct dev_pm_ops scsi_bus_pm_ops = {
+	.prepare =		scsi_bus_prepare,
+	.suspend =		scsi_bus_suspend,
+	.resume =		scsi_bus_resume,
+	.freeze =		scsi_bus_freeze,
+	.thaw =			scsi_bus_thaw,
+	.poweroff =		scsi_bus_poweroff,
+	.restore =		scsi_bus_restore,
+	.runtime_suspend =	scsi_runtime_suspend,
+	.runtime_resume =	scsi_runtime_resume,
+	.runtime_idle =		scsi_runtime_idle,
+};