diff options
| author | Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com> | 2020-06-04 16:51:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-04 19:06:26 -0700 |
| commit | e1c3cdb26ab881b77486dc50370356a349077c74 (patch) | |
| tree | dc5ef6ebebbdc59ab3c4ecedbe8d574a72abb0c1 /drivers/rapidio | |
| parent | 762a3af6faa0682e5b30b67b1db156c7df55f2c7 (diff) | |
| download | linux-e1c3cdb26ab881b77486dc50370356a349077c74.tar.bz2 | |
rapidio: avoid data race between file operation callbacks and mport_cdev_add().
Fields of md(mport_dev) are set after cdev_device_add(). However, the
file operation callbacks can be called after cdev_device_add() and
therefore accesses to fields of md in the callbacks can race with the rest
of the mport_cdev_add() function.
One such example is INIT_LIST_HEAD(&md->portwrites) in mport_cdev_add(),
the list is initialised after cdev_device_add(). This can race with
list_add_tail(&pw_filter->md_node,&md->portwrites) in
rio_mport_add_pw_filter() which is called by unlocked_ioctl.
To avoid such data races use cdev_device_add() after initializing md.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Alexandre Bounine <alex.bou9@gmail.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Mike Marshall <hubcap@omnibond.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Pavel Andrianov <andrianov@ispras.ru>
Link: http://lkml.kernel.org/r/20200426112950.1803-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/rapidio')
| -rw-r--r-- | drivers/rapidio/devices/rio_mport_cdev.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c index 10af330153b5..0b85a80ae7ef 100644 --- a/drivers/rapidio/devices/rio_mport_cdev.c +++ b/drivers/rapidio/devices/rio_mport_cdev.c @@ -2384,13 +2384,6 @@ static struct mport_dev *mport_cdev_add(struct rio_mport *mport) cdev_init(&md->cdev, &mport_fops); md->cdev.owner = THIS_MODULE; - ret = cdev_device_add(&md->cdev, &md->dev); - if (ret) { - rmcd_error("Failed to register mport %d (err=%d)", - mport->id, ret); - goto err_cdev; - } - INIT_LIST_HEAD(&md->doorbells); spin_lock_init(&md->db_lock); INIT_LIST_HEAD(&md->portwrites); @@ -2410,6 +2403,13 @@ static struct mport_dev *mport_cdev_add(struct rio_mport *mport) #else md->properties.transfer_mode |= RIO_TRANSFER_MODE_TRANSFER; #endif + + ret = cdev_device_add(&md->cdev, &md->dev); + if (ret) { + rmcd_error("Failed to register mport %d (err=%d)", + mport->id, ret); + goto err_cdev; + } ret = rio_query_mport(mport, &attr); if (!ret) { md->properties.flags = attr.flags; |