| Message ID | 1441883893-20596-1-git-send-email-sudipm.mukherjee@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | dd85ebf681ef0ee1fc985c353dd45e8b53b5dc1e |
| Headers | show |
Hi On 09/10/2015 02:18 PM, Sudip Mukherjee wrote: > During the last close we are freeing spidev if spidev->spi is NULL, but > just before checking if spidev->spi is NULL we are dereferencing it. > Lets add a check there to avoid the NULL dereference. > > Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org> > --- > drivers/spi/spidev.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c > index fba92a5..ef008e5 100644 > --- a/drivers/spi/spidev.c > +++ b/drivers/spi/spidev.c > @@ -651,7 +651,8 @@ static int spidev_release(struct inode *inode, struct file *filp) > kfree(spidev->rx_buffer); > spidev->rx_buffer = NULL; > > - spidev->speed_hz = spidev->spi->max_speed_hz; > + if (spidev->spi) > + spidev->speed_hz = spidev->spi->max_speed_hz; > > /* ... after we unbound from the underlying device? */ > spin_lock_irq(&spidev->spi_lock); Actually this fixes a *real* NULL dereference case but it is not related to normal open/close life cycle of spidev. It requires that spidev is kept open when SPI master is removed. spidev->spi is set to NULL in spidev_remove() and it is called before spidev_release() in case master is removed while spidev is in use It would be good to update this to commit log, add a tag below and Cc <stable@vger.kernel.org> Fixes: 9169051617df ("spi: spidev: Don't mangle max_speed_hz in underlying spi device") You can add these too: Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Sep 11, 2015 at 03:11:32PM +0300, Jarkko Nikula wrote: > Actually this fixes a *real* NULL dereference case but it is not related to > normal open/close life cycle of spidev. It requires that spidev is kept open > when SPI master is removed. > spidev->spi is set to NULL in spidev_remove() and it is called before > spidev_release() in case master is removed while spidev is in use > It would be good to update this to commit log, add a tag below and Cc > <stable@vger.kernel.org> > Fixes: 9169051617df ("spi: spidev: Don't mangle max_speed_hz in underlying > spi device") The patch was already applied :(
On Fri, Sep 11, 2015 at 01:25:13PM +0100, Mark Brown wrote: > On Fri, Sep 11, 2015 at 03:11:32PM +0300, Jarkko Nikula wrote: > > > Actually this fixes a *real* NULL dereference case but it is not related to > > normal open/close life cycle of spidev. It requires that spidev is kept open > > when SPI master is removed. > > > spidev->spi is set to NULL in spidev_remove() and it is called before > > spidev_release() in case master is removed while spidev is in use > > > It would be good to update this to commit log, add a tag below and Cc > > <stable@vger.kernel.org> > > > Fixes: 9169051617df ("spi: spidev: Don't mangle max_speed_hz in underlying > > spi device") > > The patch was already applied :( Applied? But usually I will receive an auto mail from you after applying. I dont think I have received any. regards sudip -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Sep 11, 2015 at 06:19:45PM +0530, Sudip Mukherjee wrote: > On Fri, Sep 11, 2015 at 01:25:13PM +0100, Mark Brown wrote: > > The patch was already applied :( > Applied? But usually I will receive an auto mail from you after applying. > I dont think I have received any. You get a mail when the changes are pushed, which had happened by the time I replied.
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index fba92a5..ef008e5 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -651,7 +651,8 @@ static int spidev_release(struct inode *inode, struct file *filp) kfree(spidev->rx_buffer); spidev->rx_buffer = NULL; - spidev->speed_hz = spidev->spi->max_speed_hz; + if (spidev->spi) + spidev->speed_hz = spidev->spi->max_speed_hz; /* ... after we unbound from the underlying device? */ spin_lock_irq(&spidev->spi_lock);
During the last close we are freeing spidev if spidev->spi is NULL, but just before checking if spidev->spi is NULL we are dereferencing it. Lets add a check there to avoid the NULL dereference. Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org> --- drivers/spi/spidev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)