Re: [PATCH] can: etas_es58x: fix error handling
flat view
From: Pavel Skripkin <hidden>
Date: 2021-11-15 07:40:50
Also in:
linux-can, lkml
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 [off-list ref] wrote:quoted
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#n2234I see, will fix in v2
quoted hunk ↗ jump to hunk
quoted
Signed-off-by: Pavel Skripkin <redacted> --- 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.cb/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(structes58x_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