On Mon, May 23, 2022 at 10:06:37PM +0300, Kalle Valo wrote:
> Johan Hovold <johan@xxxxxxxxxx> 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@xxxxxxxxxx>
> >> ---
> >
> > 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
