ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faultsgrafted

When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set,
a user fault may trigger show_pte() without any lock.
If another thread in the same process concurrently calls munmap(),
the page table pages may be freed while show_pte() is still traversing
them, causing a use-after-free in show_pte().

If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table
of PMD are freed when show_pte() is running.

Acquire mmap_write_lock() around show_pte() for user faults to fix the
contention.

For user faults, additionally restrict that show_pte() is called only
when the addr is a user-space address (addr < TASK_SIZE). This is because
the lock of tsk->mm only protects the virtual memory of user address space,
furthermore, dumping the page tables of a kernel-space address for user
faults is unnecessary and may have security implications.

Keep everything unchanged for kernel faults, because the kernel is
already in the "oops" state, acquiring a lock may risk a deadlock.

Co-developed-by: Qi Xi <xiqi2@huawei.com>

Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults")
Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Qi Xi <xiqi2@huawei.com>
Signed-off-by: Xie Yuanbin <xieyuanbin1@huawei.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 121 insertions, 0 deletions

diff --git a/include/trace/events/sof.h b/include/trace/events/sof.h
new file mode 100644
index 000000000..3061423c0
--- /dev/null
+++ b/include/trace/events/sof.h
@@ -0,0 +1,121 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright(c) 2022 Intel Corporation
+ *
+ * Author: Noah Klayman <noah.klayman@intel.com>
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM sof
+
+#if !defined(_TRACE_SOF_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SOF_H
+#include <linux/tracepoint.h>
+#include <linux/types.h>
+#include <sound/sof/stream.h>
+#include "../../../sound/soc/sof/sof-audio.h"
+
+DECLARE_EVENT_CLASS(sof_widget_template,
+	TP_PROTO(struct snd_sof_widget *swidget),
+	TP_ARGS(swidget),
+	TP_STRUCT__entry(
+		__string(name, swidget->widget->name)
+		__field(int, use_count)
+	),
+	TP_fast_assign(
+		__assign_str(name);
+		__entry->use_count = swidget->use_count;
+	),
+	TP_printk("name=%s use_count=%d", __get_str(name), __entry->use_count)
+);
+
+DEFINE_EVENT(sof_widget_template, sof_widget_setup,
+	TP_PROTO(struct snd_sof_widget *swidget),
+	TP_ARGS(swidget)
+);
+
+DEFINE_EVENT(sof_widget_template, sof_widget_free,
+	TP_PROTO(struct snd_sof_widget *swidget),
+	TP_ARGS(swidget)
+);
+
+TRACE_EVENT(sof_ipc3_period_elapsed_position,
+	TP_PROTO(struct snd_sof_dev *sdev, struct sof_ipc_stream_posn *posn),
+	TP_ARGS(sdev, posn),
+	TP_STRUCT__entry(
+		__string(device_name, dev_name(sdev->dev))
+		__field(u64, host_posn)
+		__field(u64, dai_posn)
+		__field(u64, wallclock)
+	),
+	TP_fast_assign(
+		__assign_str(device_name);
+		__entry->host_posn = posn->host_posn;
+		__entry->dai_posn = posn->dai_posn;
+		__entry->wallclock = posn->wallclock;
+	),
+	TP_printk("device_name=%s host_posn=%#llx dai_posn=%#llx wallclock=%#llx",
+		  __get_str(device_name), __entry->host_posn, __entry->dai_posn,
+		  __entry->wallclock)
+);
+
+TRACE_EVENT(sof_pcm_pointer_position,
+	TP_PROTO(struct snd_sof_dev *sdev,
+		struct snd_sof_pcm *spcm,
+		struct snd_pcm_substream *substream,
+		snd_pcm_uframes_t dma_posn,
+		snd_pcm_uframes_t dai_posn
+	),
+	TP_ARGS(sdev, spcm, substream, dma_posn, dai_posn),
+	TP_STRUCT__entry(
+		__string(device_name, dev_name(sdev->dev))
+		__field(u32, pcm_id)
+		__field(int, stream)
+		__field(unsigned long, dma_posn)
+		__field(unsigned long, dai_posn)
+	),
+	TP_fast_assign(
+		__assign_str(device_name);
+		__entry->pcm_id = le32_to_cpu(spcm->pcm.pcm_id);
+		__entry->stream = substream->stream;
+		__entry->dma_posn = dma_posn;
+		__entry->dai_posn = dai_posn;
+	),
+	TP_printk("device_name=%s pcm_id=%d stream=%d dma_posn=%lu dai_posn=%lu",
+		  __get_str(device_name), __entry->pcm_id, __entry->stream,
+		  __entry->dma_posn, __entry->dai_posn)
+);
+
+TRACE_EVENT(sof_stream_position_ipc_rx,
+	TP_PROTO(struct device *dev),
+	TP_ARGS(dev),
+	TP_STRUCT__entry(
+		__string(device_name, dev_name(dev))
+	),
+	TP_fast_assign(
+		__assign_str(device_name);
+	),
+	TP_printk("device_name=%s", __get_str(device_name))
+);
+
+TRACE_EVENT(sof_ipc4_fw_config,
+	TP_PROTO(struct snd_sof_dev *sdev, char *key, u32 value),
+	TP_ARGS(sdev, key, value),
+	TP_STRUCT__entry(
+		__string(device_name, dev_name(sdev->dev))
+		__string(key, key)
+		__field(u32, value)
+	),
+	TP_fast_assign(
+		__assign_str(device_name);
+		__assign_str(key);
+		__entry->value = value;
+	),
+	TP_printk("device_name=%s key=%s value=%d",
+		  __get_str(device_name), __get_str(key), __entry->value)
+);
+
+#endif /* _TRACE_SOF_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>