From: Laura Abbott <labbott@redhat.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Luca Coelho <luca@coelho.fi>
Cc: linux-kernel@vger.kernel.org,
Johannes Berg <johannes.berg@intel.com>,
Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
Intel Linux Wireless <linuxwifi@intel.com>,
Kalle Valo <kvalo@codeaurora.org>,
linux-wireless@vger.kernel.org,
Luca Coelho <luciano.coelho@intel.com>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH] iwlwifi: properly check debugfs dentry before using it
Date: Mon, 1 Apr 2019 08:39:26 -0700 [thread overview]
Message-ID: <50bffbea-69b5-71f4-0b9c-aead1ffc54da@redhat.com> (raw)
In-Reply-To: <20190330093152.GB14300@kroah.com>
On 3/30/19 2:31 AM, Greg Kroah-Hartman wrote:
> debugfs can now report an error code if something went wrong instead of
> just NULL. So if the return value is to be used as a "real" dentry, it
> needs to be checked if it is an error before dereferencing it.
>
> This is now happening because of ff9fb72bc077 ("debugfs: return error
> values, not NULL"). If multiple iwlwifi devices are in the system, this
> can cause problems when the driver attempts to create the main debugfs
> directory again. Later on in the code we fail horribly by trying to
> dereference a pointer that is an error value.
>
> Reported-by: Laura Abbott <labbott@redhat.com>
Can you add
Reported-by: Gabriel Ramirez <gabriello.ramirez@gmail.com>
for the bugzilla reporter who took the time to do the bisect?
I'll ask for testing as well.
> Cc: Johannes Berg <johannes.berg@intel.com>
> Cc: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
> Cc: Luca Coelho <luciano.coelho@intel.com>
> Cc: Intel Linux Wireless <linuxwifi@intel.com>
> Cc: Kalle Valo <kvalo@codeaurora.org>
> Cc: stable <stable@vger.kernel.org> # 5.0
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
>
> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
> index 2453ceabf00d..6925527d8457 100644
> --- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
> +++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
> @@ -774,8 +774,7 @@ void iwl_mvm_vif_dbgfs_register(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
> return;
>
> mvmvif->dbgfs_dir = debugfs_create_dir("iwlmvm", dbgfs_dir);
> -
> - if (!mvmvif->dbgfs_dir) {
> + if (IS_ERR_OR_NULL(mvmvif->dbgfs_dir)) {
> IWL_ERR(mvm, "Failed to create debugfs directory under %pd\n",
> dbgfs_dir);
> return;
>
next prev parent reply other threads:[~2019-04-01 15:39 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-22 15:21 [PATCH] iwlwifi: mvm: no need to check return value of debugfs_create functions Greg Kroah-Hartman
2019-01-25 19:30 ` Luciano Coelho
2019-03-26 23:55 ` Laura Abbott
2019-03-27 1:26 ` Greg Kroah-Hartman
2019-03-27 1:47 ` Laura Abbott
2019-03-27 1:53 ` Greg Kroah-Hartman
2019-03-27 6:35 ` Luca Coelho
2019-03-30 9:22 ` Greg Kroah-Hartman
2019-03-30 9:31 ` [PATCH] iwlwifi: properly check debugfs dentry before using it Greg Kroah-Hartman
2019-04-01 15:39 ` Laura Abbott [this message]
2019-04-17 7:02 ` Luca Coelho
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