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| author | Dan Williams <dan.j.williams@intel.com> | 2016-03-09 14:08:10 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-09 15:43:42 -0800 |
| commit | d77a117e6871ff78a06def46583d23752593de60 (patch) | |
| tree | 79bf0536897d69bcca3832dd77f4ac1ce6ec034e /lib/list_debug.c | |
| parent | 06b241f32c711d7ca868a0351dd97fe91fd8817b (diff) | |
| download | lwn-d77a117e6871ff78a06def46583d23752593de60.tar.gz lwn-d77a117e6871ff78a06def46583d23752593de60.zip | |
list: kill list_force_poison()
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 5c2c2587b132 ("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>
Diffstat (limited to 'lib/list_debug.c')
| -rw-r--r-- | lib/list_debug.c | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/lib/list_debug.c b/lib/list_debug.c index 3345a089ef7b..3859bf63561c 100644 --- a/lib/list_debug.c +++ b/lib/list_debug.c @@ -12,13 +12,6 @@ #include <linux/kernel.h> #include <linux/rculist.h> -static struct list_head force_poison; -void list_force_poison(struct list_head *entry) -{ - entry->next = &force_poison; - entry->prev = &force_poison; -} - /* * Insert a new entry between two known consecutive entries. * @@ -30,8 +23,6 @@ void __list_add(struct list_head *new, struct list_head *prev, struct list_head *next) { - WARN(new->next == &force_poison || new->prev == &force_poison, - "list_add attempted on force-poisoned entry\n"); WARN(next->prev != prev, "list_add corruption. next->prev should be " "prev (%p), but was %p. (next=%p).\n", |