On Wed, Mar 18, 2020 at 3:34 PM Daniel Vetter <daniel@xxxxxxxx> wrote: > > On Tue, Mar 17, 2020 at 11:33 PM Qiujun Huang <hqjagain@xxxxxxxxx> wrote: > > > > On Wed, Mar 18, 2020 at 1:02 AM Daniel Vetter <daniel@xxxxxxxx> wrote: > > > > > > On Mon, Mar 16, 2020 at 03:18:23PM +0800, Qiujun Huang wrote: > > > > We should hold idr_mutex for idr_alloc. > > > > > > > > Signed-off-by: Qiujun Huang <hqjagain@xxxxxxxxx> > > > > > > I've not seen the first version of this anywhere in my inbox, not sure > > > where that got lost. > > > > > > Anyway, this seems like a false positive - I'm assuming this was caught > > > with KCSAN. The commit message really should mention that. > > > > > > fill_object_idr creates the idr, which yes is only access later on under > > > the idr_mutex. But here it's not yet visible to any other thread, and > > > hence lockless access is safe and correct. > > > > Agree that. > > Do you know what the recommended annotation for kcsan false positives > like this should be? Adding kcsan author Marco. Actually it's not reported by kcsan. I found idr_alloc isn't safe for parallel modifications, and I didn't understand it's a exclusive path here. :) > -Daniel > -- > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
