diff mbox series

[RFC] ath11k: fix netdev open race

Message ID 20220517103436.15867-1-johan+linaro@kernel.org
State New
Headers show
Series [RFC] ath11k: fix netdev open race | expand

Commit Message

Johan Hovold May 17, 2022, 10:34 a.m. UTC 
Make sure to allocate resources needed before registering the device.

This specifically avoids having a racing open() trigger a BUG_ON() in
mod_timer() when ath11k_mac_op_start() is called before the
mon_reap_timer as been set up.

Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Fixes: 840c36fa727a ("ath11k: dp: stop rx pktlog before suspend")
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---

I started hitting a BUG_ON() during ath11k probe due to a timer which
hasn't been initialised. Turns out the netdev is registered before
having been fully set up:

[  421.232410] ath11k_core_pdev_create
[  421.233854] ath11k_dp_pdev_alloc
[  421.233863] ath11k_dp_rx_pdev_srng_alloc
[  421.259161] ath11k_mac_config_mon_status_default - NULL reap timer function
[  421.259165] ath11k_pci 0006:01:00.0: failed to configure monitor status ring with default rx_filter: (-22)
[  421.373066] ath11k_dp_rx_pdev_srng_alloc - reap timer setup

Sending as an RFC as I'm not familiar with the code. It looks like
ath11k_dp_pdev_alloc() may need to be split in an alloc and attach
function.

Johan


 drivers/net/wireless/ath/ath11k/core.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

Johan Hovold May 23, 2022, 2:48 p.m. UTC | #1 
On Tue, May 17, 2022 at 12:34:36PM +0200, Johan Hovold wrote:
> Make sure to allocate resources needed before registering the device.
> 
> This specifically avoids having a racing open() trigger a BUG_ON() in
> mod_timer() when ath11k_mac_op_start() is called before the
> mon_reap_timer as been set up.
> 
> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
> Fixes: 840c36fa727a ("ath11k: dp: stop rx pktlog before suspend")
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---

For completeness:

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3

Johan
Kalle Valo May 23, 2022, 7:06 p.m. UTC | #2 
Johan Hovold <johan@kernel.org> writes:

> On Tue, May 17, 2022 at 12:34:36PM +0200, Johan Hovold wrote:
>> Make sure to allocate resources needed before registering the device.
>> 
>> This specifically avoids having a racing open() trigger a BUG_ON() in
>> mod_timer() when ath11k_mac_op_start() is called before the
>> mon_reap_timer as been set up.
>> 
>> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
>> Fixes: 840c36fa727a ("ath11k: dp: stop rx pktlog before suspend")
>> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
>> ---
>
> For completeness:
>
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3

Thanks, added in the pending branch.

You submitted this as RFC but do you mind if I apply this anyway? The
patch looks good and passes my tests. But I do wonder why I haven't seen
the crash...
Johan Hovold May 24, 2022, 7:26 a.m. UTC | #3 
On Mon, May 23, 2022 at 10:06:37PM +0300, Kalle Valo wrote:
> Johan Hovold <johan@kernel.org> writes:
> 
> > On Tue, May 17, 2022 at 12:34:36PM +0200, Johan Hovold wrote:
> >> Make sure to allocate resources needed before registering the device.
> >> 
> >> This specifically avoids having a racing open() trigger a BUG_ON() in
> >> mod_timer() when ath11k_mac_op_start() is called before the
> >> mon_reap_timer as been set up.
> >> 
> >> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
> >> Fixes: 840c36fa727a ("ath11k: dp: stop rx pktlog before suspend")
> >> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> >> ---
> >
> > For completeness:
> >
> > Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3
> 
> Thanks, added in the pending branch.
> 
> You submitted this as RFC but do you mind if I apply this anyway? The
> patch looks good and passes my tests. But I do wonder why I haven't seen
> the crash...

If it looks good to you then please do apply it.

I was just worried that there may be some subtle reason for why
ath11k_dp_pdev_alloc() was called after netdev registration in the first
place and that it might need to be split up so that for example
ath11k_dp_rx_pdev_mon_attach() isn't called until after registration.

I did not see this issue with next-20220310, but I hit it on every probe
with next-20220511. Perhaps some timing changed in between.

Here's the backtrace for completeness in case someone else starts hitting
this and searches the archives:

[   51.346947] kernel BUG at kernel/time/timer.c:990!
[   51.346958] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
...
[   51.578225] Call trace:
[   51.583293]  __mod_timer+0x298/0x390
[   51.589518]  mod_timer+0x14/0x20
[   51.595368]  ath11k_mac_op_start+0x41c/0x4a0 [ath11k]
[   51.603165]  drv_start+0x38/0x60 [mac80211]
[   51.610110]  ieee80211_do_open+0x29c/0x7d0 [mac80211]
[   51.617945]  ieee80211_open+0x60/0xb0 [mac80211]
[   51.625311]  __dev_open+0x100/0x1c0
[   51.631420]  __dev_change_flags+0x194/0x210
[   51.638214]  dev_change_flags+0x24/0x70
[   51.644646]  do_setlink+0x228/0xdb0
[   51.650723]  __rtnl_newlink+0x460/0x830
[   51.657162]  rtnl_newlink+0x4c/0x80
[   51.663229]  rtnetlink_rcv_msg+0x124/0x390
[   51.669917]  netlink_rcv_skb+0x58/0x130
[   51.676314]  rtnetlink_rcv+0x18/0x30
[   51.682460]  netlink_unicast+0x250/0x310
[   51.688960]  netlink_sendmsg+0x19c/0x3e0
[   51.695458]  ____sys_sendmsg+0x220/0x290
[   51.701938]  ___sys_sendmsg+0x7c/0xc0
[   51.708148]  __sys_sendmsg+0x68/0xd0
[   51.714254]  __arm64_sys_sendmsg+0x28/0x40
[   51.720900]  invoke_syscall+0x48/0x120

Johan
Kalle Valo May 27, 2022, 12:06 p.m. UTC | #4 
Johan Hovold <johan@kernel.org> writes:

> On Mon, May 23, 2022 at 10:06:37PM +0300, Kalle Valo wrote:
>> Johan Hovold <johan@kernel.org> writes:
>> 
>> > On Tue, May 17, 2022 at 12:34:36PM +0200, Johan Hovold wrote:
>> >> Make sure to allocate resources needed before registering the device.
>> >> 
>> >> This specifically avoids having a racing open() trigger a BUG_ON() in
>> >> mod_timer() when ath11k_mac_op_start() is called before the
>> >> mon_reap_timer as been set up.
>> >> 
>> >> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
>> >> Fixes: 840c36fa727a ("ath11k: dp: stop rx pktlog before suspend")
>> >> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
>> >> ---
>> >
>> > For completeness:
>> >
>> > Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3
>> 
>> Thanks, added in the pending branch.
>> 
>> You submitted this as RFC but do you mind if I apply this anyway? The
>> patch looks good and passes my tests. But I do wonder why I haven't seen
>> the crash...
>
> If it looks good to you then please do apply it.
>
> I was just worried that there may be some subtle reason for why
> ath11k_dp_pdev_alloc() was called after netdev registration in the first
> place and that it might need to be split up so that for example
> ath11k_dp_rx_pdev_mon_attach() isn't called until after registration.

At least I'm not aware of anything like that? Any comments from others?

> I did not see this issue with next-20220310, but I hit it on every probe
> with next-20220511. Perhaps some timing changed in between.
>
> Here's the backtrace for completeness in case someone else starts hitting
> this and searches the archives:
>
> [   51.346947] kernel BUG at kernel/time/timer.c:990!
> [   51.346958] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
> ...
> [   51.578225] Call trace:
> [   51.583293]  __mod_timer+0x298/0x390
> [   51.589518]  mod_timer+0x14/0x20
> [   51.595368]  ath11k_mac_op_start+0x41c/0x4a0 [ath11k]
> [   51.603165]  drv_start+0x38/0x60 [mac80211]
> [   51.610110]  ieee80211_do_open+0x29c/0x7d0 [mac80211]
> [   51.617945]  ieee80211_open+0x60/0xb0 [mac80211]
> [   51.625311]  __dev_open+0x100/0x1c0
> [   51.631420]  __dev_change_flags+0x194/0x210
> [   51.638214]  dev_change_flags+0x24/0x70
> [   51.644646]  do_setlink+0x228/0xdb0
> [   51.650723]  __rtnl_newlink+0x460/0x830
> [   51.657162]  rtnl_newlink+0x4c/0x80
> [   51.663229]  rtnetlink_rcv_msg+0x124/0x390
> [   51.669917]  netlink_rcv_skb+0x58/0x130
> [   51.676314]  rtnetlink_rcv+0x18/0x30
> [   51.682460]  netlink_unicast+0x250/0x310
> [   51.688960]  netlink_sendmsg+0x19c/0x3e0
> [   51.695458]  ____sys_sendmsg+0x220/0x290
> [   51.701938]  ___sys_sendmsg+0x7c/0xc0
> [   51.708148]  __sys_sendmsg+0x68/0xd0
> [   51.714254]  __arm64_sys_sendmsg+0x28/0x40
> [   51.720900]  invoke_syscall+0x48/0x120

Thanks, this is good info and I added this to the commit log.
Kalle Valo May 30, 2022, 11:19 a.m. UTC | #5 
Johan Hovold <johan+linaro@kernel.org> wrote:

> Make sure to allocate resources needed before registering the device.
> 
> This specifically avoids having a racing open() trigger a BUG_ON() in
> mod_timer() when ath11k_mac_op_start() is called before the
> mon_reap_timer as been set up.
> 
> I did not see this issue with next-20220310, but I hit it on every probe
> with next-20220511. Perhaps some timing changed in between.
> 
> Here's the backtrace:
> 
> [   51.346947] kernel BUG at kernel/time/timer.c:990!
> [   51.346958] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
> ...
> [   51.578225] Call trace:
> [   51.583293]  __mod_timer+0x298/0x390
> [   51.589518]  mod_timer+0x14/0x20
> [   51.595368]  ath11k_mac_op_start+0x41c/0x4a0 [ath11k]
> [   51.603165]  drv_start+0x38/0x60 [mac80211]
> [   51.610110]  ieee80211_do_open+0x29c/0x7d0 [mac80211]
> [   51.617945]  ieee80211_open+0x60/0xb0 [mac80211]
> [   51.625311]  __dev_open+0x100/0x1c0
> [   51.631420]  __dev_change_flags+0x194/0x210
> [   51.638214]  dev_change_flags+0x24/0x70
> [   51.644646]  do_setlink+0x228/0xdb0
> [   51.650723]  __rtnl_newlink+0x460/0x830
> [   51.657162]  rtnl_newlink+0x4c/0x80
> [   51.663229]  rtnetlink_rcv_msg+0x124/0x390
> [   51.669917]  netlink_rcv_skb+0x58/0x130
> [   51.676314]  rtnetlink_rcv+0x18/0x30
> [   51.682460]  netlink_unicast+0x250/0x310
> [   51.688960]  netlink_sendmsg+0x19c/0x3e0
> [   51.695458]  ____sys_sendmsg+0x220/0x290
> [   51.701938]  ___sys_sendmsg+0x7c/0xc0
> [   51.708148]  __sys_sendmsg+0x68/0xd0
> [   51.714254]  __arm64_sys_sendmsg+0x28/0x40
> [   51.720900]  invoke_syscall+0x48/0x120
> 
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3
> 
> Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
> Fixes: 840c36fa727a ("ath11k: dp: stop rx pktlog before suspend")
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

Patch applied to ath-next branch of ath.git, thanks.

d4ba1ff87b17 ath11k: fix netdev open race
diff mbox series

Patch

diff --git a/drivers/net/wireless/ath/ath11k/core.c b/drivers/net/wireless/ath/ath11k/core.c
index ea073be60c12..e090dfbfa4e2 100644
--- a/drivers/net/wireless/ath/ath11k/core.c
+++ b/drivers/net/wireless/ath/ath11k/core.c
@@ -1218,23 +1218,23 @@  static int ath11k_core_pdev_create(struct ath11k_base *ab)
 		return ret;
 	}
 
-	ret = ath11k_mac_register(ab);
+	ret = ath11k_dp_pdev_alloc(ab);
 	if (ret) {
-		ath11k_err(ab, "failed register the radio with mac80211: %d\n", ret);
+		ath11k_err(ab, "failed to attach DP pdev: %d\n", ret);
 		goto err_pdev_debug;
 	}
 
-	ret = ath11k_dp_pdev_alloc(ab);
+	ret = ath11k_mac_register(ab);
 	if (ret) {
-		ath11k_err(ab, "failed to attach DP pdev: %d\n", ret);
-		goto err_mac_unregister;
+		ath11k_err(ab, "failed register the radio with mac80211: %d\n", ret);
+		goto err_dp_pdev_free;
 	}
 
 	ret = ath11k_thermal_register(ab);
 	if (ret) {
 		ath11k_err(ab, "could not register thermal device: %d\n",
 			   ret);
-		goto err_dp_pdev_free;
+		goto err_mac_unregister;
 	}
 
 	ret = ath11k_spectral_init(ab);
@@ -1247,10 +1247,10 @@  static int ath11k_core_pdev_create(struct ath11k_base *ab)
 
 err_thermal_unregister:
 	ath11k_thermal_unregister(ab);
-err_dp_pdev_free:
-	ath11k_dp_pdev_free(ab);
 err_mac_unregister:
 	ath11k_mac_unregister(ab);
+err_dp_pdev_free:
+	ath11k_dp_pdev_free(ab);
 err_pdev_debug:
 	ath11k_debugfs_pdev_destroy(ab);