On Wed, May 01, 2024 at 10:57:38AM -0500, Mike Christie wrote: > On 5/1/24 2:50 AM, Hillf Danton wrote: > > On Wed, 1 May 2024 02:01:20 -0400 Michael S. Tsirkin <mst@xxxxxxxxxx> > >> > >> and then it failed testing. > >> > > So did my patch [1] but then the reason was spotted [2,3] > > > > [1] https://lore.kernel.org/lkml/20240430110209.4310-1-hdanton@xxxxxxxx/ > > [2] https://lore.kernel.org/lkml/20240430225005.4368-1-hdanton@xxxxxxxx/ > > [3] https://lore.kernel.org/lkml/000000000000a7f8470617589ff2@xxxxxxxxxx/ > > Just to make sure I understand the conclusion. > > Edward's patch that just swaps the order of the calls: > > https://lore.kernel.org/lkml/tencent_546DA49414E876EEBECF2C78D26D242EE50A@xxxxxx/ > > fixes the UAF. I tested the same in my setup. However, when you guys tested it > with sysbot, it also triggered a softirq/RCU warning. > > The softirq/RCU part of the issue is fixed with this commit: > > https://lore.kernel.org/all/20240427102808.29356-1-qiang.zhang1211@xxxxxxxxx/ > > commit 1dd1eff161bd55968d3d46bc36def62d71fb4785 > Author: Zqiang <qiang.zhang1211@xxxxxxxxx> > Date: Sat Apr 27 18:28:08 2024 +0800 > > softirq: Fix suspicious RCU usage in __do_softirq() > > The problem was that I was testing with -next master which has that patch. > It looks like you guys were testing against bb7a2467e6be which didn't have > the patch, and so that's why you guys still hit the softirq/RCU issue. Later > when you added that patch to your patch, it worked with syzbot. > > So is it safe to assume that the softirq/RCU patch above will be upstream > when the vhost changes go in or is there a tag I need to add to my patches? Two points: - I do not want bisect broken. If you depend on this patch either I pick it too before your patch, or we defer until 1dd1eff161bd55968d3d46bc36def62d71fb4785 is merged. You can also ask for that patch to be merged in this cycle. - Do not assume - pls push somewhere a hash based on vhost that syzbot can test and confirm all is well. Thanks!
