| Message ID | 1502109470-2945-1-git-send-email-avolkov@ispras.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Aug 07, 2017 at 03:37:50PM +0300, Anton Volkov wrote: > +err_out: > return err; Any reason you can't just use return err; at the respective callsites? Thanks, Johannes
This is more of a style-oriented suggestion. This kind of template is commonly used in other modules. Regards, Anton On 07.08.2017 15:54, Johannes Thumshirn wrote: > On Mon, Aug 07, 2017 at 03:37:50PM +0300, Anton Volkov wrote: >> +err_out: >> return err; > > Any reason you can't just use return err; at the respective callsites? > > Thanks, > Johannes > -- Anton Volkov Linux Verification Center, ISPRAS web: http://linuxtesting.org e-mail: avolkov@ispras.ru
On Mon, Aug 07, 2017 at 04:09:12PM +0300, Anton Volkov wrote: > This is more of a style-oriented suggestion. This kind of template is > commonly used in other modules. Yes but there is no point in using gotos here (i.e. cleanup to be done), you an just return directly. And yes it is a minor nit. Anyways, Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
On Mon, Aug 07, 2017 at 03:37:50PM +0300, Anton Volkov wrote: > 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> Hi, Anton, Were you able to reproduce this issue or was it purely theoretical? If the former, it'd be nice if you could add a test case to blktests [1]. 1: https://github.com/osandov/blktests Thanks! Omar
Hello, Omar. It was a purely theoretical race that had been considered to be possible in real-life. Regards, Anton On 09.08.2017 01:00, Omar Sandoval wrote: > On Mon, Aug 07, 2017 at 03:37:50PM +0300, Anton Volkov wrote: >> 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> > > Hi, Anton, > > Were you able to reproduce this issue or was it purely theoretical? If > the former, it'd be nice if you could add a test case to blktests [1]. > > 1: https://github.com/osandov/blktests > > Thanks! > Omar > -- Anton Volkov Linux Verification Center, ISPRAS web: http://linuxtesting.org e-mail: avolkov@ispras.ru
On 08/07/2017 06:37 AM, Anton Volkov wrote: > 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). Added for 4.14, thanks.
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index ef83349..2fbd4089 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; }