diff options
| author | Alexander Potapenko <glider@google.com> | 2017-01-23 15:06:43 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-01-23 16:30:28 +0100 |
| commit | 4d608baac5f4e72b033a122b2d6d9499532c3afc (patch) | |
| tree | 4cc869d09280f2f09b536efb9cd7719910a2940f /block | |
| parent | blk-mq: allow resize of scheduler requests (diff) | |
| download | linux-4d608baac5f4e72b033a122b2d6d9499532c3afc.tar.xz linux-4d608baac5f4e72b033a122b2d6d9499532c3afc.zip | |
block: Initialize cfqq->ioprio_class in cfq_get_queue()
KMSAN (KernelMemorySanitizer, a new error detection tool) reports use of
uninitialized memory in cfq_init_cfqq():
==================================================================
BUG: KMSAN: use of unitialized memory
...
Call Trace:
[< inline >] __dump_stack lib/dump_stack.c:15
[<ffffffff8202ac97>] dump_stack+0x157/0x1d0 lib/dump_stack.c:51
[<ffffffff813e9b65>] kmsan_report+0x205/0x360 ??:?
[<ffffffff813eabbb>] __msan_warning+0x5b/0xb0 ??:?
[< inline >] cfq_init_cfqq block/cfq-iosched.c:3754
[<ffffffff8201e110>] cfq_get_queue+0xc80/0x14d0 block/cfq-iosched.c:3857
...
origin:
[<ffffffff8103ab37>] save_stack_trace+0x27/0x50 arch/x86/kernel/stacktrace.c:67
[<ffffffff813e836b>] kmsan_internal_poison_shadow+0xab/0x150 ??:?
[<ffffffff813e88ab>] kmsan_poison_slab+0xbb/0x120 ??:?
[< inline >] allocate_slab mm/slub.c:1627
[<ffffffff813e533f>] new_slab+0x3af/0x4b0 mm/slub.c:1641
[< inline >] new_slab_objects mm/slub.c:2407
[<ffffffff813e0ef3>] ___slab_alloc+0x323/0x4a0 mm/slub.c:2564
[< inline >] __slab_alloc mm/slub.c:2606
[< inline >] slab_alloc_node mm/slub.c:2669
[<ffffffff813dfb42>] kmem_cache_alloc_node+0x1d2/0x1f0 mm/slub.c:2746
[<ffffffff8201d90d>] cfq_get_queue+0x47d/0x14d0 block/cfq-iosched.c:3850
...
==================================================================
(the line numbers are relative to 4.8-rc6, but the bug persists
upstream)
The uninitialized struct cfq_queue is created by kmem_cache_alloc_node()
and then passed to cfq_init_cfqq(), which accesses cfqq->ioprio_class
before it's initialized.
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/cfq-iosched.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 37aeb20fa454..c472886c727f 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3864,6 +3864,8 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, goto out; } + /* cfq_init_cfqq() assumes cfqq->ioprio_class is initialized. */ + cfqq->ioprio_class = IOPRIO_CLASS_NONE; cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync); cfq_init_prio_data(cfqq, cic); cfq_link_cfqq_cfqg(cfqq, cfqg); |