On Thu, Feb 28, 2019 at 10:07:26AM -0500, Sasha Levin wrote: > From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > [ Upstream commit ff9fb72bc07705c00795ca48631f7fffe24d2c6b ] > > When an error happens, debugfs should return an error pointer value, not > NULL. This will prevent the totally theoretical error where a debugfs > call fails due to lack of memory, returning NULL, and that dentry value > is then passed to another debugfs call, which would end up succeeding, > creating a file at the root of the debugfs tree, but would then be > impossible to remove (because you can not remove the directory NULL). > > So, to make everyone happy, always return errors, this makes the users > of debugfs much simpler (they do not have to ever check the return > value), and everyone can rest easy. > > Reported-by: Gary R Hook <ghook@xxxxxxx> > Reported-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> > Reported-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > Reported-by: Michal Hocko <mhocko@xxxxxxxxxx> > Reported-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Reported-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > fs/debugfs/inode.c | 39 ++++++++++++++++++++++----------------- > 1 file changed, 22 insertions(+), 17 deletions(-) As much as I would love to backport this patch, no, please do not, I did not mark it for stable on purpose. It can cause regressions with code that is not expecting this behavior (I have a fix that needs to go into 5.0 for this very reason.) Please drop it from all queues. thanks, greg k-h
