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/xtensa.h | 49 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 include/sound/sof/xtensa.h (limited to 'include/sound/sof/xtensa.h') diff --git a/include/sound/sof/xtensa.h b/include/sound/sof/xtensa.h new file mode 100644 index 000000000..ef70f8e26 --- /dev/null +++ b/include/sound/sof/xtensa.h @@ -0,0 +1,49 @@ +/* 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) 2018 Intel Corporation + */ + +#ifndef __INCLUDE_SOUND_SOF_XTENSA_H__ +#define __INCLUDE_SOUND_SOF_XTENSA_H__ + +#include + +/* + * Architecture specific debug + */ + +/* Xtensa Firmware Oops data */ +struct sof_ipc_dsp_oops_xtensa { + struct sof_ipc_dsp_oops_arch_hdr arch_hdr; + struct sof_ipc_dsp_oops_plat_hdr plat_hdr; + uint32_t exccause; + uint32_t excvaddr; + uint32_t ps; + uint32_t epc1; + uint32_t epc2; + uint32_t epc3; + uint32_t epc4; + uint32_t epc5; + uint32_t epc6; + uint32_t epc7; + uint32_t eps2; + uint32_t eps3; + uint32_t eps4; + uint32_t eps5; + uint32_t eps6; + uint32_t eps7; + uint32_t depc; + uint32_t intenable; + uint32_t interrupt; + uint32_t sar; + uint32_t debugcause; + uint32_t windowbase; + uint32_t windowstart; + uint32_t excsave1; + uint32_t ar[]; +} __packed; + +#endif -- cgit v1.3.1