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SubjectRe: [PATCH] rtlwifi: Add the missing rcu_read_lock/unlock
On 02/27/2011 02:59 PM, Alessio Igor Bogani wrote:
> ===================================================
> [ INFO: suspicious rcu_dereference_check() usage. ]
> ---------------------------------------------------
> net/mac80211/sta_info.c:125 invoked rcu_dereference_check() without protection!
>
> other info that might help us debug this:
>
> rcu_scheduler_active = 1, debug_locks = 0
> 5 locks held by wpa_supplicant/468:
> #0: (rtnl_mutex){+.+.+.}, at: [<c1465d84>] rtnl_lock+0x14/0x20
> #1: (&rdev->mtx){+.+.+.}, at: [<f84b8c2b>] cfg80211_mgd_wext_siwfreq+0x6b/0x170 [cfg80211]
> #2: (&rdev->devlist_mtx){+.+.+.}, at: [<f84b8c37>] cfg80211_mgd_wext_siwfreq+0x77/0x170 [cfg80211]
> #3: (&wdev->mtx){+.+.+.}, at: [<f84b8c44>] cfg80211_mgd_wext_siwfreq+0x84/0x170 [cfg80211]
> #4: (&rtlpriv->locks.conf_mutex){+.+.+.}, at: [<f8506476>] rtl_op_bss_info_changed+0x26/0xc10 [rtlwifi]
>
> stack backtrace:
> Pid: 468, comm: wpa_supplicant Not tainted 2.6.38-rc6+ #79
> Call Trace:
> [<c108806a>] ? lockdep_rcu_dereference+0xaa/0xb0
> [<f8523d2c>] ? sta_info_get_bss+0x19c/0x1b0 [mac80211]
> [<f8523d62>] ? ieee80211_find_sta+0x22/0x40 [mac80211]
> [<f850661c>] ? rtl_op_bss_info_changed+0x1cc/0xc10 [rtlwifi]
> [<c153671c>] ? __mutex_unlock_slowpath+0x14c/0x160
> [<c153673d>] ? mutex_unlock+0xd/0x10
> [<f8507180>] ? rtl_op_config+0x120/0x310 [rtlwifi]
> [<c10896db>] ? trace_hardirqs_on+0xb/0x10
> [<f8522169>] ? ieee80211_bss_info_change_notify+0xf9/0x1f0 [mac80211]
> [<f8506450>] ? rtl_op_bss_info_changed+0x0/0xc10 [rtlwifi]
> [<f853646f>] ? ieee80211_set_channel+0xbf/0xd0 [mac80211]
> [<f84b5f41>] ? cfg80211_set_freq+0x121/0x180 [cfg80211]
> [<f85363b0>] ? ieee80211_set_channel+0x0/0xd0 [mac80211]
> [<f84b8ceb>] ? cfg80211_mgd_wext_siwfreq+0x12b/0x170 [cfg80211]
> [<f84b87eb>] ? cfg80211_wext_siwfreq+0x9b/0x100 [cfg80211]
> [<c153b98b>] ? sub_preempt_count+0x7b/0xb0
> [<c150f874>] ? ioctl_standard_call+0x74/0x3b0
> [<c1465d84>] ? rtnl_lock+0x14/0x20
> [<f84b8750>] ? cfg80211_wext_siwfreq+0x0/0x100 [cfg80211]
> [<c14568bd>] ? __dev_get_by_name+0x8d/0xb0
> [<c150fddb>] ? wext_handle_ioctl+0x16b/0x180
> [<f84b8750>] ? cfg80211_wext_siwfreq+0x0/0x100 [cfg80211]
> [<c145bc7a>] ? dev_ioctl+0x5ba/0x720
> [<c108a947>] ? __lock_acquire+0x3e7/0x19b0
> [<c1443b0b>] ? sock_ioctl+0x1eb/0x290
> [<c108bfa5>] ? lock_release_non_nested+0x95/0x2f0
> [<c1443920>] ? sock_ioctl+0x0/0x290
> [<c114d74d>] ? do_vfs_ioctl+0x7d/0x5c0
> [<c1112232>] ? might_fault+0x62/0xb0
> [<c113e3c6>] ? fget_light+0x226/0x390
> [<c1112278>] ? might_fault+0xa8/0xb0
> [<c114dd17>] ? sys_ioctl+0x87/0x90
> [<c1002f9f>] ? sysenter_do_call+0x12/0x38
>
> This work was supported by a hardware donation from the CE Linux Forum.
>
> Signed-off-by: Alessio Igor Bogani<abogani@kernel.org>
> ---
> drivers/net/wireless/rtlwifi/core.c | 4 ++++
> drivers/net/wireless/rtlwifi/rtl8192ce/trx.c | 5 ++++-
> 2 files changed, 8 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/wireless/rtlwifi/core.c b/drivers/net/wireless/rtlwifi/core.c
> index d6a924a..b93f12d 100644
> --- a/drivers/net/wireless/rtlwifi/core.c
> +++ b/drivers/net/wireless/rtlwifi/core.c
> @@ -552,6 +552,7 @@ static void rtl_op_bss_info_changed(struct ieee80211_hw *hw,
> RT_TRACE(rtlpriv, COMP_MAC80211, DBG_TRACE,
> ("BSS_CHANGED_HT\n"));
>
> + rcu_read_lock();
> sta = ieee80211_find_sta(mac->vif, mac->bssid);
>
> if (sta) {
> @@ -564,6 +565,7 @@ static void rtl_op_bss_info_changed(struct ieee80211_hw *hw,
> mac->current_ampdu_factor =
> sta->ht_cap.ampdu_factor;
> }
> + rcu_read_unlock();
>
> rtlpriv->cfg->ops->set_hw_reg(hw, HW_VAR_SHORTGI_DENSITY,
> (u8 *) (&mac->max_mss_density));
> @@ -615,6 +617,7 @@ static void rtl_op_bss_info_changed(struct ieee80211_hw *hw,
> else
> mac->mode = WIRELESS_MODE_G;
>
> + rcu_read_lock();
> sta = ieee80211_find_sta(mac->vif, mac->bssid);
>
> if (sta) {
> @@ -649,6 +652,7 @@ static void rtl_op_bss_info_changed(struct ieee80211_hw *hw,
> */
> }
> }
> + rcu_read_unlock();
>
> /*mac80211 just give us CCK rates any time
> *So we add G rate in basic rates when
> diff --git a/drivers/net/wireless/rtlwifi/rtl8192ce/trx.c b/drivers/net/wireless/rtlwifi/rtl8192ce/trx.c
> index bf5852f..8a8b0e2 100644
> --- a/drivers/net/wireless/rtlwifi/rtl8192ce/trx.c
> +++ b/drivers/net/wireless/rtlwifi/rtl8192ce/trx.c
> @@ -729,7 +729,7 @@ void rtl92ce_tx_fill_desc(struct ieee80211_hw *hw,
> struct rtl_ps_ctl *ppsc = rtl_psc(rtl_priv(hw));
> bool b_defaultadapter = true;
>
> - struct ieee80211_sta *sta = ieee80211_find_sta(mac->vif, mac->bssid);
> + struct ieee80211_sta *sta;
>
> u8 *pdesc = (u8 *) pdesc_tx;
> struct rtl_tcb_desc tcb_desc;
> @@ -811,10 +811,13 @@ void rtl92ce_tx_fill_desc(struct ieee80211_hw *hw,
> SET_TX_DESC_LINIP(pdesc, 0);
> SET_TX_DESC_PKT_SIZE(pdesc, (u16) skb->len);
>
> + rcu_read_lock();
> + sta = ieee80211_find_sta(mac->vif, mac->bssid);
> if (sta) {
> u8 ampdu_density = sta->ht_cap.ampdu_density;
> SET_TX_DESC_AMPDU_DENSITY(pdesc, ampdu_density);
> }
> + rcu_read_unlock();
>
> if (info->control.hw_key) {
> struct ieee80211_key_conf *keyconf =

When I turned RCU lock debugging on, I got the same diagnostic.

BTW, drivers/net/wireless/rtlwifi/rtl8192cu/trx.c has the same problem in
rtl92cu_tx_fill_desc() as you found in the rtl8192ce version of the routine. Do
you want to include that in a V2 of the patch, or should I prepare a second one?

For the content of this one, ACK.

Larry


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