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| author | Christoph Hellwig <hch@lst.de> | 2017-01-24 14:50:19 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-01-24 07:55:53 -0700 |
| commit | 690e5325b8c7d5db05fc569c0f7b888bb4248272 (patch) | |
| tree | b9c39916a4397b1eb628e07e4fc6aff91219e393 /fs | |
| parent | a4685d2f58e2230d4e27fb2ee581d7ea35e5d046 (diff) | |
| download | linux-690e5325b8c7d5db05fc569c0f7b888bb4248272.tar.gz linux-690e5325b8c7d5db05fc569c0f7b888bb4248272.tar.bz2 linux-690e5325b8c7d5db05fc569c0f7b888bb4248272.zip | |
block: fix use after free in __blkdev_direct_IO
We can't dereference the dio structure after submitting the last bio for
this request, as I/O completion might have happened before the code is
run. Introduce a local is_sync variable instead.
Fixes: 542ff7bf ("block: new direct I/O implementation")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Matias Bjørling <m@bjorling.me>
Tested-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/block_dev.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 5db5d1340d69..3c47614a4b32 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -331,7 +331,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) struct blk_plug plug; struct blkdev_dio *dio; struct bio *bio; - bool is_read = (iov_iter_rw(iter) == READ); + bool is_read = (iov_iter_rw(iter) == READ), is_sync; loff_t pos = iocb->ki_pos; blk_qc_t qc = BLK_QC_T_NONE; int ret; @@ -344,7 +344,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) bio_get(bio); /* extra ref for the completion handler */ dio = container_of(bio, struct blkdev_dio, bio); - dio->is_sync = is_sync_kiocb(iocb); + dio->is_sync = is_sync = is_sync_kiocb(iocb); if (dio->is_sync) dio->waiter = current; else @@ -398,7 +398,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) } blk_finish_plug(&plug); - if (!dio->is_sync) + if (!is_sync) return -EIOCBQUEUED; for (;;) { |