diff options
| author | Anton Volkov <avolkov@ispras.ru> | 2017-08-07 15:37:50 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-08-15 21:49:20 +0300 |
| commit | a8c1d064d3e80aa9e3ca39e908391e433cc53f78 (patch) | |
| tree | e6f2c12bab61e12cf34d1b8815bb224d63a482cb /drivers/block/loop.c | |
| parent | b3193bc0dca9bb69c8ba1ec1a318105c76eb4172 (diff) | |
| download | linux-a8c1d064d3e80aa9e3ca39e908391e433cc53f78.tar.xz | |
loop: fix to a race condition due to the early registration of device
The early device registration made possible a race leading to allocations
of disks with wrong minors.
This patch moves the device registration further down the loop_init
function to make the race infeasible.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Anton Volkov <avolkov@ispras.ru>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/loop.c')
| -rw-r--r-- | drivers/block/loop.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index ef8334949b42..2fbd4089c20e 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1996,10 +1996,6 @@ static int __init loop_init(void) struct loop_device *lo; int err; - err = misc_register(&loop_misc); - if (err < 0) - return err; - part_shift = 0; if (max_part > 0) { part_shift = fls(max_part); @@ -2017,12 +2013,12 @@ static int __init loop_init(void) if ((1UL << part_shift) > DISK_MAX_PARTS) { err = -EINVAL; - goto misc_out; + goto err_out; } if (max_loop > 1UL << (MINORBITS - part_shift)) { err = -EINVAL; - goto misc_out; + goto err_out; } /* @@ -2041,6 +2037,11 @@ static int __init loop_init(void) range = 1UL << MINORBITS; } + err = misc_register(&loop_misc); + if (err < 0) + goto err_out; + + if (register_blkdev(LOOP_MAJOR, "loop")) { err = -EIO; goto misc_out; @@ -2060,6 +2061,7 @@ static int __init loop_init(void) misc_out: misc_deregister(&loop_misc); +err_out: return err; } |