On 06/07/2018 05:13 PM, Cong Wang wrote:
On Thu, Jun 7, 2018 at 4:48 PM, <gree...@candelatech.com> wrote:
From: Ben Greear <gree...@candelatech.com>
While testing an ath10k firmware that often crashed under load,
I was seeing kernel crashes as well. One of them appeared to
be a dereference of a NULL flow object in fq_tin_dequeue.
I have since fixed the firmware flaw, but I think it would be
worth adding the WARN_ON in case the problem appears again.
BUG: unable to handle kernel NULL pointer dereference at 000000000000003c
IP: ieee80211_tx_dequeue+0xfb/0xb10 [mac80211]
Instead of adding WARN_ON(), you need to think about
the locking there, it is suspicious:
fq is from struct ieee80211_local:
struct fq *fq = &local->fq;
tin is from struct txq_info:
struct fq_tin *tin = &txqi->tin;
I don't know if fq and tin are supposed to be 1:1, if not there is
a bug in the locking, because ->new_flows and ->old_flows are
both inside tin instead of fq, but they are protected by fq->lock....
Maybe whoever put this code together can take a stab at it.
Thanks,
Ben
--
Ben Greear <gree...@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
