Messages in this thread |  | | Subject | Re: [RFC 1/7] mac80211: Add check for napi handle before WARN_ON | From | Johannes Berg <> | Date | Thu, 23 Jul 2020 22:06:46 +0200 |
| |
On Thu, 2020-07-23 at 23:56 +0530, Rakesh Pillai wrote:
> > > - WARN_ON_ONCE(softirq_count() == 0); > > > + WARN_ON_ONCE(napi && softirq_count() == 0); > > > > FWIW, I'm pretty sure this is incorrect - we make assumptions on > > softirqs being disabled in mac80211 for serialization and in place of > > some locking, I believe. > > > > I checked this, but let me double confirm. > But after this change, no packet is submitted from driver in a softirq context. > So ideally this should take care of serialization.
I'd guess that we have some reliance on BHs already being disabled, for things like u64 sync updates, or whatnot. I mean, we did "rx_ni()" for a reason ... Maybe lockdep can help catch some of the issues.
But couldn't you be in a thread and have BHs disabled too?
johannes
|  |