| Message ID | 20211114205839.15316-1-paskripkin@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | can: etas_es58x: fix error handling | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Series ignored based on subject |
Hi Pavel, Thanks for the patch! On Mon. 15 Nov 2021 at 05:58, Pavel Skripkin <paskripkin@gmail.com> wrote: > When register_candev() fails there are 2 possible device states: > NETREG_UNINITIALIZED and NETREG_UNREGISTERED. None of them are suitable > for calling unregister_candev(), because of following checks in > unregister_netdevice_many(): > > if (dev->reg_state == NETREG_UNINITIALIZED) > WARN_ON(1); > ... > BUG_ON(dev->reg_state != NETREG_REGISTERED); > > To avoid possible BUG_ON or WARN_ON let's free current netdev before > returning from es58x_init_netdev() and leave others (registered) > net devices for es58x_free_netdevs(). > > Fixes: 004653f0abf2 ("can: etas_es58x: add es58x_free_netdevs() to factorize code") Fixes: 8537257874e9 ("can: etas_es58x: add core support for ETAS ES58X CAN USB interfaces") The bug existed from the initial commit. Prior to the introduction of es58x_free_netdevs(), unregister_candev() was called in the error handling of es58x_probe(): https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/can/usb/etas_es58x/es58x_core.c?id=8537257874e949a59c834cecfd5a063e11b64b0b#n2234 > Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> > --- > drivers/net/can/usb/etas_es58x/es58x_core.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c > index 96a13c770e4a..41c721f2fbbe 100644 > --- a/drivers/net/can/usb/etas_es58x/es58x_core.c > +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c > @@ -2098,8 +2098,11 @@ static int es58x_init_netdev(struct es58x_device *es58x_dev, int channel_idx) > netdev->flags |= IFF_ECHO; /* We support local echo */ > > ret = register_candev(netdev); > - if (ret) > + if (ret) { > + free_candev(netdev); > + es58x_dev->netdev[channel_idx] = NULL; A nitpick, but if you don’t mind, I would prefer to set es58x_dev->netdev[channel_idx] after register_candev() succeeds so that we do not have to reset it to NULL in the error handling. diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c index ce2b9e1ce3af..fb0daad9b9c8 100644 --- a/drivers/net/can/usb/etas_es58x/es58x_core.c +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c @@ -2091,18 +2091,20 @@ static int es58x_init_netdev(struct es58x_device *es58x_dev, int channel_idx) return -ENOMEM; } SET_NETDEV_DEV(netdev, dev); - es58x_dev->netdev[channel_idx] = netdev; es58x_init_priv(es58x_dev, es58x_priv(netdev), channel_idx); netdev->netdev_ops = &es58x_netdev_ops; netdev->flags |= IFF_ECHO; /* We support local echo */ ret = register_candev(netdev); - if (ret) + if (ret) { + free_candev(netdev); return ret; + } netdev_queue_set_dql_min_limit(netdev_get_tx_queue(netdev, 0), es58x_dev->param->dql_min_limit); + es58x_dev->netdev[channel_idx] = netdev; return ret; } > return ret; > + } > > netdev_queue_set_dql_min_limit(netdev_get_tx_queue(netdev, 0), > es58x_dev->param->dql_min_limit);
On 11/15/21 08:27, Vincent MAILHOL wrote: > Hi Pavel, > > Thanks for the patch! > > On Mon. 15 Nov 2021 at 05:58, Pavel Skripkin <paskripkin@gmail.com> wrote: >> When register_candev() fails there are 2 possible device states: >> NETREG_UNINITIALIZED and NETREG_UNREGISTERED. None of them are suitable >> for calling unregister_candev(), because of following checks in >> unregister_netdevice_many(): >> >> if (dev->reg_state == NETREG_UNINITIALIZED) >> WARN_ON(1); >> ... >> BUG_ON(dev->reg_state != NETREG_REGISTERED); >> >> To avoid possible BUG_ON or WARN_ON let's free current netdev before >> returning from es58x_init_netdev() and leave others (registered) >> net devices for es58x_free_netdevs(). >> >> Fixes: 004653f0abf2 ("can: etas_es58x: add es58x_free_netdevs() to factorize code") > Hi, Vincent! > Fixes: 8537257874e9 ("can: etas_es58x: add core support for ETAS ES58X > CAN USB interfaces") > > The bug existed from the initial commit. Prior to the > introduction of es58x_free_netdevs(), unregister_candev() was > called in the error handling of es58x_probe(): > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/can/usb/etas_es58x/es58x_core.c?id=8537257874e949a59c834cecfd5a063e11b64b0b#n2234 > I see, will fix in v2 >> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> >> --- >> drivers/net/can/usb/etas_es58x/es58x_core.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c >> index 96a13c770e4a..41c721f2fbbe 100644 >> --- a/drivers/net/can/usb/etas_es58x/es58x_core.c >> +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c >> @@ -2098,8 +2098,11 @@ static int es58x_init_netdev(struct es58x_device *es58x_dev, int channel_idx) >> netdev->flags |= IFF_ECHO; /* We support local echo */ >> >> ret = register_candev(netdev); >> - if (ret) >> + if (ret) { >> + free_candev(netdev); >> + es58x_dev->netdev[channel_idx] = NULL; > > A nitpick, but if you don’t mind, I would prefer to set > es58x_dev->netdev[channel_idx] after register_candev() succeeds > so that we do not have to reset it to NULL in the error handling. > > diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c > b/drivers/net/can/usb/etas_es58x/es58x_core.c > index ce2b9e1ce3af..fb0daad9b9c8 100644 > --- a/drivers/net/can/usb/etas_es58x/es58x_core.c > +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c > @@ -2091,18 +2091,20 @@ static int es58x_init_netdev(struct > es58x_device *es58x_dev, int channel_idx) > return -ENOMEM; > } > SET_NETDEV_DEV(netdev, dev); > - es58x_dev->netdev[channel_idx] = netdev; > es58x_init_priv(es58x_dev, es58x_priv(netdev), channel_idx); > > netdev->netdev_ops = &es58x_netdev_ops; > netdev->flags |= IFF_ECHO; /* We support local echo */ > > ret = register_candev(netdev); > - if (ret) > + if (ret) { > + free_candev(netdev); > return ret; > + } > > netdev_queue_set_dql_min_limit(netdev_get_tx_queue(netdev, 0), > es58x_dev->param->dql_min_limit); > + es58x_dev->netdev[channel_idx] = netdev; > > return ret; > } > Also will do in v2. Thank you for your review :) With regards, Pavel Skripkin
diff --git a/drivers/net/can/usb/etas_es58x/es58x_core.c b/drivers/net/can/usb/etas_es58x/es58x_core.c index 96a13c770e4a..41c721f2fbbe 100644 --- a/drivers/net/can/usb/etas_es58x/es58x_core.c +++ b/drivers/net/can/usb/etas_es58x/es58x_core.c @@ -2098,8 +2098,11 @@ static int es58x_init_netdev(struct es58x_device *es58x_dev, int channel_idx) netdev->flags |= IFF_ECHO; /* We support local echo */ ret = register_candev(netdev); - if (ret) + if (ret) { + free_candev(netdev); + es58x_dev->netdev[channel_idx] = NULL; return ret; + } netdev_queue_set_dql_min_limit(netdev_get_tx_queue(netdev, 0), es58x_dev->param->dql_min_limit);
When register_candev() fails there are 2 possible device states: NETREG_UNINITIALIZED and NETREG_UNREGISTERED. None of them are suitable for calling unregister_candev(), because of following checks in unregister_netdevice_many(): if (dev->reg_state == NETREG_UNINITIALIZED) WARN_ON(1); ... BUG_ON(dev->reg_state != NETREG_REGISTERED); To avoid possible BUG_ON or WARN_ON let's free current netdev before returning from es58x_init_netdev() and leave others (registered) net devices for es58x_free_netdevs(). Fixes: 004653f0abf2 ("can: etas_es58x: add es58x_free_netdevs() to factorize code") Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> --- drivers/net/can/usb/etas_es58x/es58x_core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)