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authorChristoph Hellwig <hch@lst.de>2017-01-24 14:50:19 +0100
committerJens Axboe <axboe@fb.com>2017-01-24 07:55:53 -0700
commit690e5325b8c7d5db05fc569c0f7b888bb4248272 (patch)
treeb9c39916a4397b1eb628e07e4fc6aff91219e393 /fs
parenta4685d2f58e2230d4e27fb2ee581d7ea35e5d046 (diff)
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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.c6
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 (;;) {