Re: possible deadlock in sidtab_sid2str_put

[syzbot]

syzbot has bisected this bug to:

commit d97bd23c2d7d866e99eb3a927c742715c85a90ef
Author: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
Date:   Tue Nov 26 13:57:00 2019 +0000

    selinux: cache the SID -> context string translation

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13fe5f69e00000
start commit:   b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne..
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=10015f69e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=17fe5f69e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20
dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000

Reported-by: syzbot+61cba5033e2072d61806@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: d97bd23c2d7d ("selinux: cache the SID -> context string translation")

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