Commit beee24695157 ("cfg80211: Save the regulatory domain when
setting custom regulatory") adds a get_wiphy_regdom call to
wiphy_apply_custom_regulatory. But as the comment above
wiphy_apply_custom_regulatory says:
"/* Used by drivers prior to wiphy registration */"
this function is used by driver's probe function before the wiphy is
registered and at this point wiphy->regd will typically by NULL and
calling rcu_dereference_rtnl on a NULL pointer causes the following
warning/backtrace:
=============================
WARNING: suspicious RCU usage
5.11.0-rc1+ #19 Tainted: G W
-----------------------------
net/wireless/reg.c:144 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/2:0/22:
#0: ffff9a4bc104df38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1ee/0x570
#1: ffffb6e94010be78 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x1ee/0x570
stack backtrace:
CPU: 2 PID: 22 Comm: kworker/2:0 Tainted: G W 5.11.0-rc1+ #19
Hardware name: LENOVO 60073/INVALID, BIOS 01WT17WW 08/01/2014
Workqueue: events request_firmware_work_func
Call Trace:
dump_stack+0x8b/0xb0
get_wiphy_regdom+0x57/0x60 [cfg80211]
wiphy_apply_custom_regulatory+0xa0/0xf0 [cfg80211]
brcmf_cfg80211_attach+0xb02/0x1360 [brcmfmac]
brcmf_attach+0x189/0x460 [brcmfmac]
brcmf_sdio_firmware_callback+0x78a/0x8f0 [brcmfmac]
brcmf_fw_request_done+0x67/0xf0 [brcmfmac]
request_firmware_work_func+0x3d/0x70
process_one_work+0x26e/0x570
worker_thread+0x55/0x3c0
? process_one_work+0x570/0x570
kthread+0x137/0x150
? __kthread_bind_mask+0x60/0x60
ret_from_fork+0x22/0x30
Add a check for wiphy->regd being NULL before calling get_wiphy_regdom
(as is already done in other places) to fix this.
wiphy->regd will likely always be NULL when wiphy_apply_custom_regulatory
gets called, so arguably the tmp = get_wiphy_regdom() and
rcu_free_regdom(tmp) calls should simply be dropped, this patch keeps the
2 calls, to allow drivers to call wiphy_apply_custom_regulatory more then
once if necessary.
Cc: Ilan Peer <[email protected]>
Fixes: beee24695157 ("cfg80211: Save the regulatory domain when setting custom regulator")
Signed-off-by: Hans de Goede <[email protected]>
---
net/wireless/reg.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index bb72447ad960..9254b9cbaa21 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -2547,7 +2547,7 @@ static void handle_band_custom(struct wiphy *wiphy,
void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
const struct ieee80211_regdomain *regd)
{
- const struct ieee80211_regdomain *new_regd, *tmp;
+ const struct ieee80211_regdomain *new_regd, *tmp = NULL;
enum nl80211_band band;
unsigned int bands_set = 0;
@@ -2571,7 +2571,8 @@ void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
if (IS_ERR(new_regd))
return;
- tmp = get_wiphy_regdom(wiphy);
+ if (wiphy->regd)
+ tmp = get_wiphy_regdom(wiphy);
rcu_assign_pointer(wiphy->regd, new_regd);
rcu_free_regdom(tmp);
}
--
2.28.0
Hi,
On 1/5/21 10:24 AM, Peer, Ilan wrote:
> Hi,
>
>> -----Original Message-----
>> From: Hans de Goede <[email protected]>
>> Sent: Monday, January 04, 2021 19:07
>> To: Johannes Berg <[email protected]>; David S . Miller
>> <[email protected]>; Jakub Kicinski <[email protected]>; Rojewski,
>> Cezary <[email protected]>; Pierre-Louis Bossart <pierre-
>> [email protected]>; Liam Girdwood
>> <[email protected]>; Jie Yang <[email protected]>;
>> Mark Brown <[email protected]>
>> Cc: Hans de Goede <[email protected]>; linux-
>> [email protected]; [email protected]; linux-
>> [email protected]; [email protected]; Peer, Ilan
>> <[email protected]>
>> Subject: [PATCH] cfg80211: Fix "suspicious RCU usage in
>> wiphy_apply_custom_regulatory" warning/backtrace
>>
>> Commit beee24695157 ("cfg80211: Save the regulatory domain when setting
>> custom regulatory") adds a get_wiphy_regdom call to
>> wiphy_apply_custom_regulatory. But as the comment above
>> wiphy_apply_custom_regulatory says:
>> "/* Used by drivers prior to wiphy registration */"
>> this function is used by driver's probe function before the wiphy is registered
>> and at this point wiphy->regd will typically by NULL and calling
>> rcu_dereference_rtnl on a NULL pointer causes the following
>> warning/backtrace:
>>
>> =============================
>> WARNING: suspicious RCU usage
>> 5.11.0-rc1+ #19 Tainted: G W
>> -----------------------------
>> net/wireless/reg.c:144 suspicious rcu_dereference_check() usage!
>>
>> other info that might help us debug this:
>>
>> rcu_scheduler_active = 2, debug_locks = 1
>> 2 locks held by kworker/2:0/22:
>> #0: ffff9a4bc104df38 ((wq_completion)events){+.+.}-{0:0}, at:
>> process_one_work+0x1ee/0x570
>> #1: ffffb6e94010be78 ((work_completion)(&fw_work->work)){+.+.}-{0:0},
>> at: process_one_work+0x1ee/0x570
>>
>> stack backtrace:
>> CPU: 2 PID: 22 Comm: kworker/2:0 Tainted: G W 5.11.0-rc1+ #19
>> Hardware name: LENOVO 60073/INVALID, BIOS 01WT17WW 08/01/2014
>> Workqueue: events request_firmware_work_func Call Trace:
>> dump_stack+0x8b/0xb0
>> get_wiphy_regdom+0x57/0x60 [cfg80211]
>> wiphy_apply_custom_regulatory+0xa0/0xf0 [cfg80211]
>> brcmf_cfg80211_attach+0xb02/0x1360 [brcmfmac]
>> brcmf_attach+0x189/0x460 [brcmfmac]
>> brcmf_sdio_firmware_callback+0x78a/0x8f0 [brcmfmac]
>> brcmf_fw_request_done+0x67/0xf0 [brcmfmac]
>> request_firmware_work_func+0x3d/0x70
>> process_one_work+0x26e/0x570
>> worker_thread+0x55/0x3c0
>> ? process_one_work+0x570/0x570
>> kthread+0x137/0x150
>> ? __kthread_bind_mask+0x60/0x60
>> ret_from_fork+0x22/0x30
>>
>> Add a check for wiphy->regd being NULL before calling get_wiphy_regdom
>> (as is already done in other places) to fix this.
>>
>> wiphy->regd will likely always be NULL when
>> wiphy->wiphy_apply_custom_regulatory
>> gets called, so arguably the tmp = get_wiphy_regdom() and
>> rcu_free_regdom(tmp) calls should simply be dropped, this patch keeps the
>> 2 calls, to allow drivers to call wiphy_apply_custom_regulatory more then
>> once if necessary.
>>
>> Cc: Ilan Peer <[email protected]>
>> Fixes: beee24695157 ("cfg80211: Save the regulatory domain when setting
>> custom regulator")
>> Signed-off-by: Hans de Goede <[email protected]>
>> ---
>> net/wireless/reg.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/wireless/reg.c b/net/wireless/reg.c index
>> bb72447ad960..9254b9cbaa21 100644
>> --- a/net/wireless/reg.c
>> +++ b/net/wireless/reg.c
>> @@ -2547,7 +2547,7 @@ static void handle_band_custom(struct wiphy
>> *wiphy, void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
>> const struct ieee80211_regdomain *regd) {
>> - const struct ieee80211_regdomain *new_regd, *tmp;
>> + const struct ieee80211_regdomain *new_regd, *tmp = NULL;
>> enum nl80211_band band;
>> unsigned int bands_set = 0;
>>
>> @@ -2571,7 +2571,8 @@ void wiphy_apply_custom_regulatory(struct wiphy
>> *wiphy,
>> if (IS_ERR(new_regd))
>> return;
>>
>> - tmp = get_wiphy_regdom(wiphy);
>> + if (wiphy->regd)
>> + tmp = get_wiphy_regdom(wiphy);
>> rcu_assign_pointer(wiphy->regd, new_regd);
>> rcu_free_regdom(tmp);
>
> This only fixes the first case where the pointer in NULL and does not handle the wrong RCU usage in other cases.
>
> I'll prepare a fix for this.
Any luck with this? This is a regression in 5.11, so this really should
be fixed in a future 5.11-rc and the clock is running out.
Regards,
Hans
Hi,
This fix can be found here. It was merged to the mac80211 tree.
https://patchwork.kernel.org/project/linux-wireless/patch/iwlwifi.20210105165657.613e9a876829.Ia38d27dbebea28bf9c56d70691d243186ede70e7@changeid/
Regards,
Ilan.
> -----Original Message-----
> From: Hans de Goede <[email protected]>
> Sent: Monday, January 18, 2021 23:09
> To: Peer, Ilan <[email protected]>; Johannes Berg
> <[email protected]>; David S . Miller <[email protected]>;
> Jakub Kicinski <[email protected]>; Rojewski, Cezary
> <[email protected]>; Pierre-Louis Bossart <pierre-
> [email protected]>; Liam Girdwood
> <[email protected]>; Jie Yang <[email protected]>;
> Mark Brown <[email protected]>
> Cc: [email protected]; [email protected]; linux-
> [email protected]; [email protected]
> Subject: Re: [PATCH] cfg80211: Fix "suspicious RCU usage in
> wiphy_apply_custom_regulatory" warning/backtrace
>
> Hi,
>
> On 1/5/21 10:24 AM, Peer, Ilan wrote:
> > Hi,
> >
> >> -----Original Message-----
> >> From: Hans de Goede <[email protected]>
> >> Sent: Monday, January 04, 2021 19:07
> >> To: Johannes Berg <[email protected]>; David S . Miller
> >> <[email protected]>; Jakub Kicinski <[email protected]>; Rojewski,
> >> Cezary <[email protected]>; Pierre-Louis Bossart <pierre-
> >> [email protected]>; Liam Girdwood
> >> <[email protected]>; Jie Yang
> >> <[email protected]>; Mark Brown <[email protected]>
> >> Cc: Hans de Goede <[email protected]>; linux-
> >> [email protected]; [email protected]; linux-
> >> [email protected]; [email protected]; Peer, Ilan
> >> <[email protected]>
> >> Subject: [PATCH] cfg80211: Fix "suspicious RCU usage in
> >> wiphy_apply_custom_regulatory" warning/backtrace
> >>
> >> Commit beee24695157 ("cfg80211: Save the regulatory domain when
> >> setting custom regulatory") adds a get_wiphy_regdom call to
> >> wiphy_apply_custom_regulatory. But as the comment above
> >> wiphy_apply_custom_regulatory says:
> >> "/* Used by drivers prior to wiphy registration */"
> >> this function is used by driver's probe function before the wiphy is
> >> registered and at this point wiphy->regd will typically by NULL and
> >> calling rcu_dereference_rtnl on a NULL pointer causes the following
> >> warning/backtrace:
> >>
> >> =============================
> >> WARNING: suspicious RCU usage
> >> 5.11.0-rc1+ #19 Tainted: G W
> >> -----------------------------
> >> net/wireless/reg.c:144 suspicious rcu_dereference_check() usage!
> >>
> >> other info that might help us debug this:
> >>
> >> rcu_scheduler_active = 2, debug_locks = 1
> >> 2 locks held by kworker/2:0/22:
> >> #0: ffff9a4bc104df38 ((wq_completion)events){+.+.}-{0:0}, at:
> >> process_one_work+0x1ee/0x570
> >> #1: ffffb6e94010be78
> >> ((work_completion)(&fw_work->work)){+.+.}-{0:0},
> >> at: process_one_work+0x1ee/0x570
> >>
> >> stack backtrace:
> >> CPU: 2 PID: 22 Comm: kworker/2:0 Tainted: G W 5.11.0-rc1+ #19
> >> Hardware name: LENOVO 60073/INVALID, BIOS 01WT17WW 08/01/2014
> >> Workqueue: events request_firmware_work_func Call Trace:
> >> dump_stack+0x8b/0xb0
> >> get_wiphy_regdom+0x57/0x60 [cfg80211]
> >> wiphy_apply_custom_regulatory+0xa0/0xf0 [cfg80211]
> >> brcmf_cfg80211_attach+0xb02/0x1360 [brcmfmac]
> >> brcmf_attach+0x189/0x460 [brcmfmac]
> >> brcmf_sdio_firmware_callback+0x78a/0x8f0 [brcmfmac]
> >> brcmf_fw_request_done+0x67/0xf0 [brcmfmac]
> >> request_firmware_work_func+0x3d/0x70
> >> process_one_work+0x26e/0x570
> >> worker_thread+0x55/0x3c0
> >> ? process_one_work+0x570/0x570
> >> kthread+0x137/0x150
> >> ? __kthread_bind_mask+0x60/0x60
> >> ret_from_fork+0x22/0x30
> >>
> >> Add a check for wiphy->regd being NULL before calling
> >> get_wiphy_regdom (as is already done in other places) to fix this.
> >>
> >> wiphy->regd will likely always be NULL when
> >> wiphy->wiphy_apply_custom_regulatory
> >> gets called, so arguably the tmp = get_wiphy_regdom() and
> >> rcu_free_regdom(tmp) calls should simply be dropped, this patch keeps
> >> the
> >> 2 calls, to allow drivers to call wiphy_apply_custom_regulatory more
> >> then once if necessary.
> >>
> >> Cc: Ilan Peer <[email protected]>
> >> Fixes: beee24695157 ("cfg80211: Save the regulatory domain when
> >> setting custom regulator")
> >> Signed-off-by: Hans de Goede <[email protected]>
> >> ---
> >> net/wireless/reg.c | 5 +++--
> >> 1 file changed, 3 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/net/wireless/reg.c b/net/wireless/reg.c index
> >> bb72447ad960..9254b9cbaa21 100644
> >> --- a/net/wireless/reg.c
> >> +++ b/net/wireless/reg.c
> >> @@ -2547,7 +2547,7 @@ static void handle_band_custom(struct wiphy
> >> *wiphy, void wiphy_apply_custom_regulatory(struct wiphy *wiphy,
> >> const struct ieee80211_regdomain *regd) {
> >> - const struct ieee80211_regdomain *new_regd, *tmp;
> >> + const struct ieee80211_regdomain *new_regd, *tmp = NULL;
> >> enum nl80211_band band;
> >> unsigned int bands_set = 0;
> >>
> >> @@ -2571,7 +2571,8 @@ void wiphy_apply_custom_regulatory(struct
> wiphy
> >> *wiphy,
> >> if (IS_ERR(new_regd))
> >> return;
> >>
> >> - tmp = get_wiphy_regdom(wiphy);
> >> + if (wiphy->regd)
> >> + tmp = get_wiphy_regdom(wiphy);
> >> rcu_assign_pointer(wiphy->regd, new_regd);
> >> rcu_free_regdom(tmp);
> >
> > This only fixes the first case where the pointer in NULL and does not handle
> the wrong RCU usage in other cases.
> >
> > I'll prepare a fix for this.
>
> Any luck with this? This is a regression in 5.11, so this really should be fixed in
> a future 5.11-rc and the clock is running out.
>
> Regards,
>
> Hans