On Sun, Dec 30, 2018 at 12:00 PM Sven Eckelmann <s...@narfation.org> wrote: > > On Sunday, 30 December 2018 11.41.03 CET syzbot wrote: > [...] > > HEAD commit: d8924c0d76aa Merge tag 'devprop-4.21-rc1' of git://git.ker.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=122a373f400000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=91a256823ef17263 > > dashboard link: https://syzkaller.appspot.com/bug?extid=c764de0fcfadca9a8595 > > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16fd1d67400000 > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+c764de0fcfadca9a8...@syzkaller.appspotmail.com > > What is the bug here? The kernel module showed a warning because the parent > device cannot be found in the same netns using __dev_get_by_index. > > The test system was just configured to panic on warnings. So are we now > expected to show warnings or what is the expected behavior? > > This behavior was added with commit b7eddd0b3950 ("batman-adv: prevent using > any virtual device created on batman-adv as hard-interface") - 3d48811b27f5 in > the out-of-tree module.
Hi Sven, The problem is that kernel code uses WARNING when it should not. For WARN guidelines please see this: https://elixir.bootlin.com/linux/v4.20/source/include/asm-generic/bug.h#L81 and this (search for WARN_ON_ONCE): https://lwn.net/Articles/769365/ > Kind regards, > Sven > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7eddd0b3950ea9dc863f1cbfa30d172dbf772f4
