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, 345 insertions, 0 deletions

diff --git a/sound/hda/common/bind.c b/sound/hda/common/bind.c
new file mode 100644
index 000000000..6a728a773
--- /dev/null
+++ b/sound/hda/common/bind.c
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HD-audio codec driver binding
+ * Copyright (c) Takashi Iwai <tiwai@suse.de>
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/export.h>
+#include <linux/pm.h>
+#include <sound/core.h>
+#include <sound/hda_codec.h>
+#include "hda_local.h"
+#include "hda_jack.h"
+
+/*
+ * find a matching codec id
+ */
+static int hda_codec_match(struct hdac_device *dev, const struct hdac_driver *drv)
+{
+	struct hda_codec *codec = container_of(dev, struct hda_codec, core);
+	const struct hda_codec_driver *driver =
+		container_of(drv, struct hda_codec_driver, core);
+	const struct hda_device_id *list;
+	/* check probe_id instead of vendor_id if set */
+	u32 id = codec->probe_id ? codec->probe_id : codec->core.vendor_id;
+	u32 rev_id = codec->core.revision_id;
+
+	for (list = driver->id; list->vendor_id; list++) {
+		if (list->vendor_id == id &&
+		    (!list->rev_id || list->rev_id == rev_id)) {
+			codec->preset = list;
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/* process an unsolicited event */
+static void hda_codec_unsol_event(struct hdac_device *dev, unsigned int ev)
+{
+	struct hda_codec *codec = container_of(dev, struct hda_codec, core);
+	struct hda_codec_driver *driver = hda_codec_to_driver(codec);
+
+	/* ignore unsol events during shutdown */
+	if (codec->card->shutdown || codec->bus->shutdown)
+		return;
+
+	/* ignore unsol events during system suspend/resume */
+	if (codec->core.dev.power.power_state.event != PM_EVENT_ON)
+		return;
+
+	if (driver->ops->unsol_event)
+		driver->ops->unsol_event(codec, ev);
+}
+
+/**
+ * snd_hda_codec_set_name - set the codec name
+ * @codec: the HDA codec
+ * @name: name string to set
+ */
+int snd_hda_codec_set_name(struct hda_codec *codec, const char *name)
+{
+	int err;
+
+	if (!name)
+		return 0;
+	err = snd_hdac_device_set_chip_name(&codec->core, name);
+	if (err < 0)
+		return err;
+
+	/* update the mixer name */
+	if (!*codec->card->mixername ||
+	    codec->bus->mixer_assigned >= codec->core.addr) {
+		snprintf(codec->card->mixername,
+			 sizeof(codec->card->mixername), "%s %s",
+			 codec->core.vendor_name, codec->core.chip_name);
+		codec->bus->mixer_assigned = codec->core.addr;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_hda_codec_set_name);
+
+static int hda_codec_driver_probe(struct device *dev)
+{
+	struct hda_codec *codec = dev_to_hda_codec(dev);
+	struct module *owner = dev->driver->owner;
+	struct hda_codec_driver *driver = hda_codec_to_driver(codec);
+	int err;
+
+	if (codec->bus->core.ext_ops) {
+		if (WARN_ON(!codec->bus->core.ext_ops->hdev_attach))
+			return -EINVAL;
+		return codec->bus->core.ext_ops->hdev_attach(&codec->core);
+	}
+
+	if (WARN_ON(!codec->preset))
+		return -EINVAL;
+
+	err = snd_hda_codec_set_name(codec, codec->preset->name);
+	if (err < 0)
+		goto error;
+	err = snd_hdac_regmap_init(&codec->core);
+	if (err < 0)
+		goto error;
+
+	if (!try_module_get(owner)) {
+		err = -EINVAL;
+		goto error;
+	}
+
+	if (WARN_ON(!(driver->ops && driver->ops->probe))) {
+		err = -EINVAL;
+		goto error_module_put;
+	}
+
+	err = driver->ops->probe(codec, codec->preset);
+	if (err < 0)
+		goto error_module_put;
+	err = snd_hda_codec_build_pcms(codec);
+	if (err < 0)
+		goto error_module;
+	err = snd_hda_codec_build_controls(codec);
+	if (err < 0)
+		goto error_module;
+	/* only register after the bus probe finished; otherwise it's racy */
+	if (!codec->bus->bus_probing && codec->card->registered) {
+		err = snd_card_register(codec->card);
+		if (err < 0)
+			goto error_module;
+		snd_hda_codec_register(codec);
+	}
+
+	codec->core.lazy_cache = true;
+	return 0;
+
+ error_module:
+	if (driver->ops->remove)
+		driver->ops->remove(codec);
+ error_module_put:
+	module_put(owner);
+
+ error:
+	snd_hda_codec_cleanup_for_unbind(codec);
+	codec->preset = NULL;
+	return err;
+}
+
+static int hda_codec_driver_remove(struct device *dev)
+{
+	struct hda_codec *codec = dev_to_hda_codec(dev);
+	struct hda_codec_driver *driver = hda_codec_to_driver(codec);
+
+	if (codec->bus->core.ext_ops) {
+		if (WARN_ON(!codec->bus->core.ext_ops->hdev_detach))
+			return -EINVAL;
+		return codec->bus->core.ext_ops->hdev_detach(&codec->core);
+	}
+
+	snd_hda_codec_disconnect_pcms(codec);
+	snd_hda_jack_tbl_disconnect(codec);
+	snd_refcount_sync(&codec->pcm_ref);
+	snd_power_sync_ref(codec->bus->card);
+
+	if (driver->ops->remove)
+		driver->ops->remove(codec);
+	snd_hda_codec_cleanup_for_unbind(codec);
+	codec->preset = NULL;
+	module_put(dev->driver->owner);
+	return 0;
+}
+
+static void hda_codec_driver_shutdown(struct device *dev)
+{
+	snd_hda_codec_shutdown(dev_to_hda_codec(dev));
+}
+
+int __hda_codec_driver_register(struct hda_codec_driver *drv, const char *name,
+			       struct module *owner)
+{
+	drv->core.driver.name = name;
+	drv->core.driver.owner = owner;
+	drv->core.driver.bus = &snd_hda_bus_type;
+	drv->core.driver.probe = hda_codec_driver_probe;
+	drv->core.driver.remove = hda_codec_driver_remove;
+	drv->core.driver.shutdown = hda_codec_driver_shutdown;
+	drv->core.driver.pm = pm_ptr(&hda_codec_driver_pm);
+	drv->core.type = HDA_DEV_LEGACY;
+	drv->core.match = hda_codec_match;
+	drv->core.unsol_event = hda_codec_unsol_event;
+	return driver_register(&drv->core.driver);
+}
+EXPORT_SYMBOL_GPL(__hda_codec_driver_register);
+
+void hda_codec_driver_unregister(struct hda_codec_driver *drv)
+{
+	driver_unregister(&drv->core.driver);
+}
+EXPORT_SYMBOL_GPL(hda_codec_driver_unregister);
+
+static inline bool codec_probed(struct hda_codec *codec)
+{
+	return device_attach(hda_codec_dev(codec)) > 0 && codec->preset;
+}
+
+/* try to auto-load codec module */
+static void request_codec_module(struct hda_codec *codec)
+{
+#ifdef MODULE
+	char modalias[32];
+	const char *mod = NULL;
+
+	switch (codec->probe_id) {
+	case HDA_CODEC_ID_GENERIC_HDMI:
+#if IS_MODULE(CONFIG_SND_HDA_CODEC_HDMI)
+		mod = "snd-hda-codec-hdmi";
+#endif
+		break;
+	case HDA_CODEC_ID_GENERIC:
+#if IS_MODULE(CONFIG_SND_HDA_GENERIC)
+		mod = "snd-hda-codec-generic";
+#endif
+		break;
+	default:
+		snd_hdac_codec_modalias(&codec->core, modalias, sizeof(modalias));
+		mod = modalias;
+		break;
+	}
+
+	if (mod)
+		request_module(mod);
+#endif /* MODULE */
+}
+
+/* try to auto-load and bind the codec module */
+static void codec_bind_module(struct hda_codec *codec)
+{
+#ifdef MODULE
+	request_codec_module(codec);
+	if (codec_probed(codec))
+		return;
+#endif
+}
+
+#if IS_ENABLED(CONFIG_SND_HDA_CODEC_HDMI)
+/* if all audio out widgets are digital, let's assume the codec as a HDMI/DP */
+static bool is_likely_hdmi_codec(struct hda_codec *codec)
+{
+	hda_nid_t nid;
+
+	/*
+	 * For ASoC users, if snd_hda_hdmi_codec module is denylisted and any
+	 * event causes i915 enumeration to fail, ->wcaps remains uninitialized.
+	 */
+	if (!codec->wcaps)
+		return true;
+
+	for_each_hda_codec_node(nid, codec) {
+		unsigned int wcaps = get_wcaps(codec, nid);
+		switch (get_wcaps_type(wcaps)) {
+		case AC_WID_AUD_IN:
+			return false; /* HDMI parser supports only HDMI out */
+		case AC_WID_AUD_OUT:
+			if (!(wcaps & AC_WCAP_DIGITAL))
+				return false;
+			break;
+		}
+	}
+	return true;
+}
+#else
+/* no HDMI codec parser support */
+#define is_likely_hdmi_codec(codec)	false
+#endif /* CONFIG_SND_HDA_CODEC_HDMI */
+
+static int codec_bind_generic(struct hda_codec *codec)
+{
+	if (codec->probe_id)
+		return -ENODEV;
+
+	if (is_likely_hdmi_codec(codec)) {
+		codec->probe_id = HDA_CODEC_ID_GENERIC_HDMI;
+		request_codec_module(codec);
+		if (codec_probed(codec))
+			return 0;
+	}
+
+	codec->probe_id = HDA_CODEC_ID_GENERIC;
+	request_codec_module(codec);
+	if (codec_probed(codec))
+		return 0;
+	return -ENODEV;
+}
+
+#if IS_ENABLED(CONFIG_SND_HDA_GENERIC)
+#define is_generic_config(codec) \
+	(codec->modelname && !strcmp(codec->modelname, "generic"))
+#else
+#define is_generic_config(codec)	0
+#endif
+
+/**
+ * snd_hda_codec_configure - (Re-)configure the HD-audio codec
+ * @codec: the HDA codec
+ *
+ * Start parsing of the given codec tree and (re-)initialize the whole
+ * codec driver binding.
+ *
+ * Returns 0 if successful or a negative error code.
+ */
+int snd_hda_codec_configure(struct hda_codec *codec)
+{
+	int err;
+
+	if (codec->configured)
+		return 0;
+
+	if (is_generic_config(codec))
+		codec->probe_id = HDA_CODEC_ID_GENERIC;
+	else
+		codec->probe_id = 0;
+
+	if (!device_is_registered(&codec->core.dev)) {
+		err = snd_hdac_device_register(&codec->core);
+		if (err < 0)
+			return err;
+	}
+
+	if (!codec->preset)
+		codec_bind_module(codec);
+	if (!codec->preset) {
+		err = codec_bind_generic(codec);
+		if (err < 0) {
+			codec_dbg(codec, "Unable to bind the codec\n");
+			return err;
+		}
+	}
+
+	codec->configured = 1;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_hda_codec_configure);