Re: [syzbot] WARNING in trc_read_check_handler

[Paul E. McKenney]

On Wed, Dec 01, 2021 at 12:50:07PM -0800, syzbot wrote:
> syzbot suspects this issue was fixed by commit:
> 
> commit 96017bf9039763a2e02dcc6adaa18592cd73a39d
> Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
> Date:   Wed Jul 28 17:53:41 2021 +0000
> 
>     rcu-tasks: Simplify trc_read_check_handler() atomic operations
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1281d89db00000
> start commit:   5319255b8df9 selftests/bpf: Skip verifier tests that fail ..
> git tree:       bpf-next
> kernel config:  https://syzkaller.appspot.com/x/.config?x=9290a409049988d4
> dashboard link: https://syzkaller.appspot.com/bug?extid=fe9d8c955bd1d0f02dc1
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14990477300000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=105ebd84b00000
> 
> If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: rcu-tasks: Simplify trc_read_check_handler() atomic operations

> For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Give or take.  There were quite a few related bugs, so some or all of
the following commits might also have helped:

cbe0d8d91415c rcu-tasks: Wait for trc_read_check_handler() IPIs
18f08e758f34e rcu-tasks: Add trc_inspect_reader() checks for exiting critical section
46aa886c483f5 rcu-tasks: Fix IPI failure handling in trc_wait_for_one_reader

Quibbles aside, it is nice to get an automated email about having fixed
a bug as opposed to having added one.  ;-)

							Thanx, Paul