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authorBen Hutchings <ben@decadent.org.uk>2014-04-19 14:36:43 +0100
committerBen Hutchings <ben@decadent.org.uk>2014-05-18 14:58:09 +0100
commit11e835193b386b219260cc97ca01158d0e4ff58f (patch)
tree5091aed7b120fe82036a305b97842ad47db66965 /drivers
parent74627ab15f07468eab311749ce4e225135daaa8b (diff)
rtl8192ce: Fix null dereference in watchdog
Dmitry Semyonov reported that after upgrading from 3.2.54 to 3.2.57 the rtl8192ce driver will crash when its interface is brought up. The oops message shows: [ 1833.611397] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 [ 1833.611455] IP: [<ffffffffa0410c6a>] rtl92ce_update_hal_rate_tbl+0x29/0x4db [rtl8192ce] ... [ 1833.613326] Call Trace: [ 1833.613346] [<ffffffffa02ad9c6>] ? rtl92c_dm_watchdog+0xd0b/0xec9 [rtl8192c_common] [ 1833.613391] [<ffffffff8105b5cf>] ? process_one_work+0x161/0x269 [ 1833.613425] [<ffffffff8105c598>] ? worker_thread+0xc2/0x145 [ 1833.613458] [<ffffffff8105c4d6>] ? manage_workers.isra.25+0x15b/0x15b [ 1833.613496] [<ffffffff8105f6d9>] ? kthread+0x76/0x7e [ 1833.613527] [<ffffffff81356b74>] ? kernel_thread_helper+0x4/0x10 [ 1833.613563] [<ffffffff8105f663>] ? kthread_worker_fn+0x139/0x139 [ 1833.613598] [<ffffffff81356b70>] ? gs_change+0x13/0x13 Disassembly of rtl92ce_update_hal_rate_tbl() shows that the 'sta' parameter was null. None of the changes to the rtlwifi family between 3.2.54 and 3.2.57 seem to directly cause this, and reverting commit f78bccd79ba3 ('rtlwifi: rtl8192ce: Fix too long disable of IRQs') doesn't fix it. rtl92c_dm_watchdog() calls rtl92ce_update_hal_rate_tbl() via rtl92c_dm_refresh_rate_adaptive_mask(), which does not appear in the call trace as it was inlined. That function has been completely removed upstream which may explain why this crash wasn't seen there. I'm not sure that it is sensible to completely remove rtl92c_dm_refresh_rate_adaptive_mask() without making other compensating changes elsewhere, so try to work around this for 3.2 by checking for a null pointer in rtl92c_dm_refresh_rate_adaptive_mask() and then skipping the call to rtl92ce_update_hal_rate_tbl(). References: https://bugs.debian.org/745137 References: https://bugs.debian.org/745462 Reported-by: Dmitry Semyonov <linulin@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Larry Finger <Larry.Finger@lwfinger.net> Cc: Chaoming Li <chaoming_li@realsil.com.cn>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/wireless/rtlwifi/rtl8192c/dm_common.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/net/wireless/rtlwifi/rtl8192c/dm_common.c b/drivers/net/wireless/rtlwifi/rtl8192c/dm_common.c
index a004ad75d568..ba7ef2fd4997 100644
--- a/drivers/net/wireless/rtlwifi/rtl8192c/dm_common.c
+++ b/drivers/net/wireless/rtlwifi/rtl8192c/dm_common.c
@@ -1228,11 +1228,14 @@ static void rtl92c_dm_refresh_rate_adaptive_mask(struct ieee80211_hw *hw)
if (rtlhal->interface == INTF_PCI) {
rcu_read_lock();
sta = ieee80211_find_sta(mac->vif, mac->bssid);
+ if (!sta)
+ goto out_unlock;
}
rtlpriv->cfg->ops->update_rate_tbl(hw, sta,
p_ra->ratr_state);
p_ra->pre_ratr_state = p_ra->ratr_state;
+ out_unlock:
if (rtlhal->interface == INTF_PCI)
rcu_read_unlock();
}