On Mon, May 25, 2020 at 11:38:17AM +0200, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@xxxxxxxxx>
>
> Removing the "if (IS_ERR(dir)) dir = NULL;" check only works
> if we adjust the remaining code to not rely on it being NULL.
> Check IS_ERR_OR_NULL() before attempting to dereference it.
>
> I'm not actually entirely sure this fixes the syzbot crash as
> the kernel config indicates that they do have DEBUG_FS in the
> kernel, but this is what I found when looking there.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: d82574a8e5a4 ("cfg80211: no need to check return value of debugfs_create functions")
> Reported-by: syzbot+fd5332e429401bf42d18@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
> ---
> net/wireless/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/wireless/core.c b/net/wireless/core.c
> index 341402b4f178..ce024440fa51 100644
> --- a/net/wireless/core.c
> +++ b/net/wireless/core.c
> @@ -142,7 +142,7 @@ int cfg80211_dev_rename(struct cfg80211_registered_device *rdev,
> if (result)
> return result;
>
> - if (rdev->wiphy.debugfsdir)
> + if (!IS_ERR_OR_NULL(rdev->wiphy.debugfsdir))
> debugfs_rename(rdev->wiphy.debugfsdir->d_parent,
> rdev->wiphy.debugfsdir,
> rdev->wiphy.debugfsdir->d_parent, newname);
I missed that d_parent was being accessed, sorry about that. This looks
good to me:
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
