On Mon, Oct 10, 2016 at 8:17 AM, Laszlo Ersek <ler...@redhat.com> wrote: > Hi, > > Greg asked me to stick to email with this bug report, so I'm reposting > the original kernel bugzilla report to personal addresses, and lkml. > > Thanks, > Laszlo > > https://bugzilla.kernel.org/show_bug.cgi?id=177021 > > Bug ID: 177021 > Summary: [driver core] CONFIG_DEBUG_TEST_DRIVER_REMOVE causes > unremovable drivers to bind devices twice > Product: Drivers > Version: 2.5 > Kernel Version: v4.8-2283-ga3443cd (4.9.0-0.rc0.git2.1.fc26.aarch64) > Hardware: All > OS: Linux > Tree: Mainline > Status: NEW > Severity: normal > Priority: P1 > Component: Other > Assignee: drivers_ot...@kernel-bugs.osdl.org > Reporter: ler...@redhat.com > CC: a...@arndb.de, g...@kroah.com > Regression: No > > CONFIG_DEBUG_TEST_DRIVER_REMOVE was added in the following commit: > >> commit bea5b158ff0da9c7246ff391f754f5f38e34577a >> Author: Rob Herring <r...@kernel.org> >> Date: Thu Aug 11 10:20:58 2016 -0500 >> >> driver core: add test of driver remove calls during probe
[...] > This is almost a regression because the kernel crashes with valid > drivers. It is not an error for a driver to not provide a remove() > callback, so in this instance CONFIG_DEBUG_TEST_DRIVER_REMOVE does not > expose a driver bug, it breaks with a valid driver. Not a regression for > the upstream kernel after all, because the Kconfig documentation > suggests N as default. > > Proposed solution: if none of the remove() methods exist, or the > remove() method that exists fails, then don't release any resources, and > don't re-probe the device. I was thinking no remove method meant the driver didn't need to do any explicit clean-up as all resources used devres, but I guess that's not going to cover things like subsystem de-registration. I'll prepare a fix. Rob
