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https://github.com/torvalds/linux
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e3f76e3386
Use the magic LIST_POISON* values to detect an incorrect use of list_del on a deleted entry. This DEBUG_LIST specific warning is easier to understand than the generic Oops message caused by LIST_POISON dereference. Signed-off-by: Baruch Siach <baruch@tkos.co.il> Cc: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
63 lines
1.7 KiB
C
63 lines
1.7 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 implementations for
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* DEBUG_LIST.
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*/
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#include <linux/module.h>
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#include <linux/list.h>
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/*
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* Insert a new entry between two known consecutive entries.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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void __list_add(struct list_head *new,
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struct list_head *prev,
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struct list_head *next)
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{
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WARN(next->prev != prev,
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"list_add corruption. next->prev should be "
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"prev (%p), but was %p. (next=%p).\n",
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prev, next->prev, next);
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WARN(prev->next != next,
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"list_add corruption. prev->next should be "
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"next (%p), but was %p. (prev=%p).\n",
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next, prev->next, prev);
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next->prev = new;
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new->next = next;
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new->prev = prev;
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prev->next = new;
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}
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EXPORT_SYMBOL(__list_add);
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/**
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* list_del - deletes entry from list.
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* @entry: the element to delete from the list.
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* Note: list_empty on entry does not return true after this, the entry is
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* in an undefined state.
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*/
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void list_del(struct list_head *entry)
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{
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WARN(entry->next == LIST_POISON1,
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"list_del corruption, next is LIST_POISON1 (%p)\n",
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LIST_POISON1);
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WARN(entry->next != LIST_POISON1 && entry->prev == LIST_POISON2,
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"list_del corruption, prev is LIST_POISON2 (%p)\n",
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LIST_POISON2);
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WARN(entry->prev->next != entry,
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"list_del corruption. prev->next should be %p, "
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"but was %p\n", entry, entry->prev->next);
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WARN(entry->next->prev != entry,
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"list_del corruption. next->prev should be %p, "
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"but was %p\n", entry, entry->next->prev);
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__list_del(entry->prev, entry->next);
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entry->next = LIST_POISON1;
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entry->prev = LIST_POISON2;
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}
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EXPORT_SYMBOL(list_del);
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