d77a117e68
Given we have uninitialized list_heads being passed to list_add() it
will always be the case that those uninitialized values randomly trigger
the poison value. Especially since a list_add() operation will seed the
stack with the poison value for later stack allocations to trip over.
For example, see these two false positive reports:
list_add attempted on force-poisoned entry
WARNING: at lib/list_debug.c:34
[..]
NIP [c00000000043c390] __list_add+0xb0/0x150
LR [c00000000043c38c] __list_add+0xac/0x150
Call Trace:
__list_add+0xac/0x150 (unreliable)
__down+0x4c/0xf8
down+0x68/0x70
xfs_buf_lock+0x4c/0x150 [xfs]
list_add attempted on force-poisoned entry(0000000000000500),
new->next == d0000000059ecdb0, new->prev == 0000000000000500
WARNING: at lib/list_debug.c:33
[..]
NIP [c00000000042db78] __list_add+0xa8/0x140
LR [c00000000042db74] __list_add+0xa4/0x140
Call Trace:
__list_add+0xa4/0x140 (unreliable)
rwsem_down_read_failed+0x6c/0x1a0
down_read+0x58/0x60
xfs_log_commit_cil+0x7c/0x600 [xfs]
Fixes: commit 5c2c2587b1 ("mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Eryu Guan <eguan@redhat.com>
Tested-by: Eryu Guan <eguan@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
100 lines
2.6 KiB
C
100 lines
2.6 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/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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* 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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WARN(new == prev || new == next,
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"list_add double add: new=%p, prev=%p, next=%p.\n",
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new, prev, next);
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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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WRITE_ONCE(prev->next, new);
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}
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EXPORT_SYMBOL(__list_add);
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void __list_del_entry(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 (WARN(next == LIST_POISON1,
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"list_del corruption, %p->next is LIST_POISON1 (%p)\n",
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entry, LIST_POISON1) ||
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WARN(prev == LIST_POISON2,
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"list_del corruption, %p->prev is LIST_POISON2 (%p)\n",
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entry, LIST_POISON2) ||
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WARN(prev->next != entry,
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"list_del corruption. prev->next should be %p, "
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"but was %p\n", entry, prev->next) ||
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WARN(next->prev != entry,
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"list_del corruption. next->prev should be %p, "
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"but was %p\n", entry, next->prev))
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return;
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__list_del(prev, next);
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}
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EXPORT_SYMBOL(__list_del_entry);
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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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__list_del_entry(entry);
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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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/*
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* RCU variants.
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*/
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void __list_add_rcu(struct list_head *new,
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struct list_head *prev, struct list_head *next)
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{
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WARN(next->prev != prev,
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"list_add_rcu corruption. next->prev should be 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_rcu corruption. prev->next should be next (%p), but was %p. (prev=%p).\n",
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next, prev->next, prev);
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new->next = next;
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new->prev = prev;
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rcu_assign_pointer(list_next_rcu(prev), new);
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next->prev = new;
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}
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EXPORT_SYMBOL(__list_add_rcu);
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