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In some circumstances, attempts are made to add entries to or to remove entries from an uninitialized list. A prime example is amdgpu_bo_vm_destroy(): It is indirectly called from ttm_bo_init_reserved() if that function fails, and tries to remove an entry from a list. However, that list is only initialized in amdgpu_bo_create_vm() after the call to ttm_bo_init_reserved() returned success. This results in crashes such as BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 1479 Comm: chrome Not tainted 5.10.110-15768-g29a72e65dae5 Hardware name: Google Grunt/Grunt, BIOS Google_Grunt.11031.149.0 07/15/2020 RIP: 0010:__list_del_entry_valid+0x26/0x7d ... Call Trace: amdgpu_bo_vm_destroy+0x48/0x8b ttm_bo_init_reserved+0x1d7/0x1e0 amdgpu_bo_create+0x212/0x476 ? amdgpu_bo_user_destroy+0x23/0x23 ? kmem_cache_alloc+0x60/0x271 amdgpu_bo_create_vm+0x40/0x7d amdgpu_vm_pt_create+0xe8/0x24b ... Check if the list's prev and next pointers are NULL to catch such problems. Link: https://lkml.kernel.org/r/20220531222951.92073-1-linux@roeck-us.net Signed-off-by: Guenter Roeck <linux@roeck-us.net> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
71 lines
2.2 KiB
C
71 lines
2.2 KiB
C
/*
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* Copyright 2006, Red Hat, Inc., Dave Jones
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* Released under the General Public License (GPL).
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*
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* This file contains the linked list validation for DEBUG_LIST.
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*/
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#include <linux/export.h>
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#include <linux/list.h>
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#include <linux/bug.h>
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#include <linux/kernel.h>
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#include <linux/rculist.h>
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/*
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* Check that the data structures for the list manipulations are reasonably
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* valid. Failures here indicate memory corruption (and possibly an exploit
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* attempt).
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*/
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bool __list_add_valid(struct list_head *new, struct list_head *prev,
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struct list_head *next)
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{
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if (CHECK_DATA_CORRUPTION(prev == NULL,
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"list_add corruption. prev is NULL.\n") ||
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CHECK_DATA_CORRUPTION(next == NULL,
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"list_add corruption. next is NULL.\n") ||
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CHECK_DATA_CORRUPTION(next->prev != prev,
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"list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n",
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prev, next->prev, next) ||
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CHECK_DATA_CORRUPTION(prev->next != next,
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"list_add corruption. prev->next should be next (%px), but was %px. (prev=%px).\n",
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next, prev->next, prev) ||
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CHECK_DATA_CORRUPTION(new == prev || new == next,
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"list_add double add: new=%px, prev=%px, next=%px.\n",
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new, prev, next))
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return false;
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return true;
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}
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EXPORT_SYMBOL(__list_add_valid);
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bool __list_del_entry_valid(struct list_head *entry)
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{
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struct list_head *prev, *next;
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prev = entry->prev;
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next = entry->next;
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if (CHECK_DATA_CORRUPTION(next == NULL,
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"list_del corruption, %px->next is NULL\n", entry) ||
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CHECK_DATA_CORRUPTION(prev == NULL,
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"list_del corruption, %px->prev is NULL\n", entry) ||
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CHECK_DATA_CORRUPTION(next == LIST_POISON1,
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"list_del corruption, %px->next is LIST_POISON1 (%px)\n",
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entry, LIST_POISON1) ||
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CHECK_DATA_CORRUPTION(prev == LIST_POISON2,
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"list_del corruption, %px->prev is LIST_POISON2 (%px)\n",
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entry, LIST_POISON2) ||
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CHECK_DATA_CORRUPTION(prev->next != entry,
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"list_del corruption. prev->next should be %px, but was %px. (prev=%px)\n",
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entry, prev->next, prev) ||
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CHECK_DATA_CORRUPTION(next->prev != entry,
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"list_del corruption. next->prev should be %px, but was %px. (next=%px)\n",
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entry, next->prev, next))
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return false;
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return true;
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}
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EXPORT_SYMBOL(__list_del_entry_valid);
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