Re: KASAN: use-after-free Read in tcf_block_find

2018-09-27 Thread Dmitry Vyukov
On Thu, Sep 27, 2018 at 7:50 PM, Cong Wang wrote: > On Thu, Sep 27, 2018 at 1:11 AM Dmitry Vyukov wrote: >> >> Would a stack trace for call_rcu be helpful here? I have this idea for >> a long time, but never get around to implementing it: >> https://bugzilla.kernel.org/show_bug.cgi?id=198437 > >

Re: KASAN: use-after-free Read in tcf_block_find

2018-09-27 Thread Cong Wang
On Thu, Sep 27, 2018 at 1:11 AM Dmitry Vyukov wrote: > > Would a stack trace for call_rcu be helpful here? I have this idea for > a long time, but never get around to implementing it: > https://bugzilla.kernel.org/show_bug.cgi?id=198437 Yes. Generally speaking, showing backtrace of call_rcu() or

Re: KASAN: use-after-free Read in tcf_block_find

2018-09-27 Thread Dmitry Vyukov
On Thu, Sep 27, 2018 at 3:24 PM, Eric Dumazet wrote: > On 09/27/2018 06:02 AM, Dmitry Vyukov wrote: > >> I am not suggesting to commit this. This is just a hack for debugging. >> It in fact lead to some warnings, but still allowed me to reproduce >> the bug reliably. >> > > Had you got more

Re: KASAN: use-after-free Read in tcf_block_find

2018-09-27 Thread Eric Dumazet
On 09/27/2018 06:02 AM, Dmitry Vyukov wrote: > I am not suggesting to commit this. This is just a hack for debugging. > It in fact lead to some warnings, but still allowed me to reproduce > the bug reliably. > Had you got more meaningful stack traces ? (Showing which context was actually

Re: KASAN: use-after-free Read in tcf_block_find

2018-09-27 Thread Dmitry Vyukov
On Thu, Sep 27, 2018 at 3:00 PM, Eric Dumazet wrote: > > > On 09/27/2018 01:10 AM, Dmitry Vyukov wrote: > >> >> Would a stack trace for call_rcu be helpful here? I have this idea for >> a long time, but never get around to implementing it: >> https://bugzilla.kernel.org/show_bug.cgi?id=198437 >>

Re: KASAN: use-after-free Read in tcf_block_find

2018-09-27 Thread Eric Dumazet
On 09/27/2018 01:10 AM, Dmitry Vyukov wrote: > > Would a stack trace for call_rcu be helpful here? I have this idea for > a long time, but never get around to implementing it: > https://bugzilla.kernel.org/show_bug.cgi?id=198437 > > Also FWIW I recently used the following hack for another