Re: [ldv-project] [net] rtl8188ee: a potential race condition
On 06/24/2016 09:17 AM, Vaishali Thakkar wrote: On Friday 10 June 2016 01:51 PM, Pavel Andrianov wrote: 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. I think the patch was sent sometime ago for removing the parameter. But I am not sure why it's not applied. May be Larry can have better idea about this. Here, is link to the patch: http://linux-wireless.vger.kernel.narkive.com/mu4t9xxr/patch-3-4-rtlwifi-rtl8192cu-remove-unused-parameter The patch for rtl8192cu was applied as commit 4b9d8d67b44a on Jun 20 2011, but the unused parameter was reintroduced as part of an update of the power-save code with commit d3feae41a347 on Sep 22 2014. My recollection is that Realtek envisioned a driver that needed this parameter to be true. As none has yet been introduced, I will prepare a patch to remove it again. I am also testing a patch to remove the race condition in rtl8188ee. Larry
Re: [ldv-project] [net] rtl8188ee: a potential race condition
On 06/24/2016 09:17 AM, Vaishali Thakkar wrote: On Friday 10 June 2016 01:51 PM, Pavel Andrianov wrote: 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. I think the patch was sent sometime ago for removing the parameter. But I am not sure why it's not applied. May be Larry can have better idea about this. Here, is link to the patch: http://linux-wireless.vger.kernel.narkive.com/mu4t9xxr/patch-3-4-rtlwifi-rtl8192cu-remove-unused-parameter The patch for rtl8192cu was applied as commit 4b9d8d67b44a on Jun 20 2011, but the unused parameter was reintroduced as part of an update of the power-save code with commit d3feae41a347 on Sep 22 2014. My recollection is that Realtek envisioned a driver that needed this parameter to be true. As none has yet been introduced, I will prepare a patch to remove it again. I am also testing a patch to remove the race condition in rtl8188ee. Larry
Re: [ldv-project] [net] rtl8188ee: a potential race condition
On Friday 10 June 2016 01:51 PM, Pavel Andrianov wrote: > 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. I think the patch was sent sometime ago for removing the parameter. But I am not sure why it's not applied. May be Larry can have better idea about this. Here, is link to the patch: http://linux-wireless.vger.kernel.narkive.com/mu4t9xxr/patch-3-4-rtlwifi-rtl8192cu-remove-unused-parameter -- Vaishali
Re: [ldv-project] [net] rtl8188ee: a potential race condition
On Friday 10 June 2016 01:51 PM, Pavel Andrianov wrote: > 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. I think the patch was sent sometime ago for removing the parameter. But I am not sure why it's not applied. May be Larry can have better idea about this. Here, is link to the patch: http://linux-wireless.vger.kernel.narkive.com/mu4t9xxr/patch-3-4-rtlwifi-rtl8192cu-remove-unused-parameter -- Vaishali
[ldv-project] [net] rtl8188ee: a potential race condition
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: andria...@ispras.ru
[ldv-project] [net] rtl8188ee: a potential race condition
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: andria...@ispras.ru
