On Wed, Mar 30, 2022 at 10:37:22AM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: d888c83fcec7 fs: fix fd table size alignment properly > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=103e7b53700000 > kernel config: https://syzkaller.appspot.com/x/.config?x=cadd7063134e07bc > dashboard link: https://syzkaller.appspot.com/bug?extid=2778a29e60b4982065a0 > compiler: aarch64-linux-gnu-gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > userspace arch: arm64 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+2778a29e60b4982065a0@xxxxxxxxxxxxxxxxxxxxxxxxx Very likely to have been caused by commit 0a9a25ca7843 "block: let blkcg_gq grab request queue's refcnt". It had added dropping a queue refcount (which is blocking) into blkg_free(), which is called from __blkg_release(). And that is called via call_rcu() and thus is not allowed to block at all.
