On Mon, Mar 22, 2021 at 11:19:53AM +0100, Arnd Bergmann wrote: > From: Arnd Bergmann <[email protected]> > > Cleaning out the last -Wempty-body warnings found some interesting > cases with empty macros, along with harmless warnings like this one: > > drivers/base/devcoredump.c: In function 'dev_coredumpm': > drivers/base/devcoredump.c:297:56: error: suggest braces around empty body in > an 'if' statement [-Werror=empty-body] > 297 | /* nothing - symlink will be missing */; > | ^ > drivers/base/devcoredump.c:301:56: error: suggest braces around empty body in > an 'if' statement [-Werror=empty-body] > 301 | /* nothing - symlink will be missing */; > | ^ > > Randy tried addressing this one before, and there were multiple > other ideas in that thread. > > Pick up the one that Matthew Wilcox suggested by adding a > WARN_ON_ONCE() and a comment. > > Link: > https://lore.kernel.org/lkml/[email protected]/ > Cc: Randy Dunlap <[email protected]> > Cc: Matthew Wilcox <[email protected]> > Signed-off-by: Arnd Bergmann <[email protected]> > --- > drivers/base/devcoredump.c | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/drivers/base/devcoredump.c b/drivers/base/devcoredump.c > index 9243468e2c99..88e0d931439e 100644 > --- a/drivers/base/devcoredump.c > +++ b/drivers/base/devcoredump.c > @@ -292,13 +292,16 @@ void dev_coredumpm(struct device *dev, struct module > *owner, > if (device_add(&devcd->devcd_dev)) > goto put_device; > > - if (sysfs_create_link(&devcd->devcd_dev.kobj, &dev->kobj, > - "failing_device")) > - /* nothing - symlink will be missing */; > + /* > + * These should normally not fail, but there is no problem > + * continuing without the links, so just warn instead of > + * failing. > + */ > + WARN_ON_ONCE(sysfs_create_link(&devcd->devcd_dev.kobj, &dev->kobj, > + "failing_device")); > > - if (sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj, > - "devcoredump")) > - /* nothing - symlink will be missing */; > + WARN_ON_ONCE(sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj, > + "devcoredump"));
We do not want to reboot machines that have panic-on-warn set, so if this really needs a trace dump, please do that instead... thanks, greg k-h
