On Jul 26, 2019, at 10:29 PM, Linus Torvalds [off-list ref] wrote:

On Fri, Jul 26, 2019 at 4:26 PM syzbot
[off-list ref] wrote:

quoted

syzbot has bisected this bug to:

commit 0e034f5c4bc408c943f9c4a06244415d75d7108c
Author: Linus Torvalds [off-list ref]
Date:   Wed May 18 18:51:25 2016 +0000

    iwlwifi: fix mis-merge that breaks the driver

While this bisection looks more likely than the other syzbot entry
that bisected to a version change, I don't think it is correct eitger.

The bisection ended up doing a lot of "git bisect skip" because of the

   undefined reference to `nf_nat_icmp_reply_translation'

issue. Also, the memory leak doesn't seem to be entirely reliable:
when the bisect does 10 runs to verify that some test kernel is bad,
there are a couple of cases where only one or two of the ten run
failed.

Which makes me wonder if one or two of the "everything OK" runs were
actually buggy, but just happened to have all ten pass…

Real bisection should point to,

8ed633b9baf9e (“Revert "net-sysfs: Fix memory leak in netdev_register_kobject”")

I did encounter those memory leak and comes up with a similar fix in,

6b70fc94afd1 ("net-sysfs: Fix memory leak in netdev_register_kobject”)

but those error handling paths are tricky that seems nobody did much testing there, so it will
keep hitting other bugs in upper functions.