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[ldv-project] [net] rtl8188ee: a potential race condition

From Pavel Andrianov <andrianov@ispras.ru>
Newsgroups linux.kernel
Subject [ldv-project] [net] rtl8188ee: a potential race condition
Date 2016-06-10 11:30 +0200
Message-ID <rIqVj-2LW-3@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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Hi!

There is a potential data race in 
drivers/net/wireless/realtek/rtlwifi/rtl8188ee/rtl8188ee.ko.

In the function rtl88ee_gpio_radio_on_off_checking the flag 
ppsc->rfchange_inprogress is set with a spinlock protection. In the 
function rtl_ps_set_rf_state the flag is read also under a spinlock. But 
the function rtl88e_dm_watchdog read it without any locks. As a result 
rtl88e_dm_watchdog may execute the succeeding code while changing (with 
the flag rfchange_inprogress == true). I do not exactly determine the 
consequences, but likely they are not good if there exists such check. 
Could anybody more confident confirm this?

The function rtl_ps_set_rf_state is always called with its parameter 
[protect_or_not == false]. Is this flag really necessary, if the value 
'true' is never used? The function is also set the flag 
ppsc->rfchange_inprogress and may affect the rtl88e_dm_watchdog as in 
the previous case.

-- 
Pavel Andrianov
Linux Verification Center, ISPRAS
web: http://linuxtesting.org
e-mail: andrianov@ispras.ru

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[ldv-project] [net] rtl8188ee: a potential race condition Pavel Andrianov <andrianov@ispras.ru> - 2016-06-10 11:30 +0200

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