On Sat, Nov 24, 2018 at 11:20:14PM +0200, Slavomir Kaslev wrote: > On Sat, Nov 24, 2018 at 08:03:57PM +0000, Al Viro wrote: > > On Sat, Nov 24, 2018 at 11:40:03AM -0800, syzbot wrote: > > > Hello, > > > > > > syzbot found the following crash on: > > > > > > HEAD commit: edeca3a769ad Merge tag 'sound-4.20-rc4' of > > > git://git.kerne.. > > > git tree: upstream > > > console output: https://syzkaller.appspot.com/x/log.txt?x=12bee26d400000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=73e2bc0cb6463446 > > > dashboard link: > > > https://syzkaller.appspot.com/bug?extid=ce18da013d76d837144d > > > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15ccd1f5400000 > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > Reported-by: syzbot+ce18da013d76d8371...@syzkaller.appspotmail.com > > > > Caused by commit 95506588d2c1d72ca29adef8ae9bf771bcfb4ced > > Author: Slavomir Kaslev <kasl...@vmware.com> > > Date: Fri Nov 16 11:27:53 2018 +0200 > > > > socket: do a generic_file_splice_read when proto_ops has no splice_read > > > > exposing all ->recvmsg() instances to pipe-backed iov_iter as possible > > destination. > > It's not all that hard to fix (I'll probably have a candidate patch by > > tonight, > > it's just a matter of adding the only missing primitive), but... shouldn't > > that > > patch have sat in -next for at least some testing first? Because it's very > > easy to reproduce - splice from e.g. UDP socket will step into it. Sure, > > the > > sky is not falling (unless you set panic-on-WARN, that is); the damn thing > > would've failed anyway, but... > > My bad for not sending the patch tagged as net-next, feel free to revert it.
No point, IMO - the fix isn't hard and bisect hazard created by the whole thing is both mild (spurious WARN() in case that used to fail anyway) _and_ won't disappear from reverting, obviously. I'll post a fix later tonight...
