From 1039bffd6ae9c75b42b7d148d6c1106134107b66 Mon Sep 17 00:00:00 2001 From: Xie Yuanbin Date: Tue, 28 Jul 2026 03:16:42 +0100 Subject: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults 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 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) Reviewed-by: Linus Walleij Signed-off-by: Qi Xi Signed-off-by: Xie Yuanbin Signed-off-by: Russell King --- include/sound/sof/debug.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 include/sound/sof/debug.h (limited to 'include/sound/sof/debug.h') diff --git a/include/sound/sof/debug.h b/include/sound/sof/debug.h new file mode 100644 index 000000000..8b308d7e5 --- /dev/null +++ b/include/sound/sof/debug.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */ +/* + * This file is provided under a dual BSD/GPLv2 license. When using or + * redistributing this file, you may do so under either license. + * + * Copyright(c) 2020 Intel Corporation + * + * Author: Karol Trzcinski + */ + +#ifndef __INCLUDE_SOUND_SOF_DEBUG_H__ +#define __INCLUDE_SOUND_SOF_DEBUG_H__ + +#include + +/** ABI3.18 */ +enum sof_ipc_dbg_mem_zone { + SOF_IPC_MEM_ZONE_SYS = 0, /**< System zone */ + SOF_IPC_MEM_ZONE_SYS_RUNTIME = 1, /**< System-runtime zone */ + SOF_IPC_MEM_ZONE_RUNTIME = 2, /**< Runtime zone */ + SOF_IPC_MEM_ZONE_BUFFER = 3, /**< Buffer zone */ + SOF_IPC_MEM_ZONE_RUNTIME_SHARED = 4, /**< System runtime zone */ + SOF_IPC_MEM_ZONE_SYS_SHARED = 5, /**< System shared zone */ +}; + +/** ABI3.18 */ +struct sof_ipc_dbg_mem_usage_elem { + uint32_t zone; /**< see sof_ipc_dbg_mem_zone */ + uint32_t id; /**< heap index within zone */ + uint32_t used; /**< number of bytes used in zone */ + uint32_t free; /**< number of bytes free to use within zone */ + uint32_t reserved; /**< for future use */ +} __packed; + +/** ABI3.18 */ +struct sof_ipc_dbg_mem_usage { + struct sof_ipc_reply rhdr; /**< generic IPC reply header */ + uint32_t reserved[4]; /**< reserved for future use */ + uint32_t num_elems; /**< elems[] counter */ + struct sof_ipc_dbg_mem_usage_elem elems[]; /**< memory usage information */ +} __packed; + +#endif -- cgit v1.3.1