Re: [driver-core:debugfs_lookup_fix] [mm/damon/dbgfs] ff25f87cfc: kernel_BUG_at_lib/list_debug.c

[SeongJae Park <sj@kernel.org>]

On Thu, 5 Jan 2023 10:53:57 +0100 Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> On Wed, Jan 04, 2023 at 06:35:39PM +0000, SeongJae Park wrote:
> > Hello,
> > 
> > On Tue, 3 Jan 2023 21:16:09 +0800 kernel test robot <oliver.sang@intel.com> wrote:
> > 
> > > [-- Attachment #1: Type: text/plain, Size: 7528 bytes --]
> > > 
> > > 
> > > Greeting,
> > > 
> > > FYI, we noticed kernel_BUG_at_lib/list_debug.c due to commit (built with gcc-11):
> > 
> > Thank you for the report!
> > 
> > > 
> > > commit: ff25f87cfcfc34ebe652987f2a7beb184762785b ("mm/damon/dbgfs: fix memory leak when using debugfs_lookup()")
> > > https://git.kernel.org/cgit/linux/kernel/git/gregkh/driver-core.git debugfs_lookup_fix
> > 
> > The commit is for fixing a memory leak due to missed dput() call.  The patch
> > has posted originally by Greg and revised my I[1].  The revised version has
> > merged in mainline during v6.0 stabilization period (1552fd3ef7db).
> > 
> > The problematic tree (driver-core/debugfs_lookup_fix) is based on v6.2-rc2, so
> > the revised patch is already applied.  But the first version of the patch is
> > applied again on the tree[2], probably by mistake, and caused double 'dput()'.
> > 
> > So I think the commit seems needs to be reverted.
> > 
> > If there is anything I missed or wrong, please let me know.
> > 
> > [1] https://lore.kernel.org/damon/20220902191149.112434-1-sj@kernel.org/
> > [2] https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git/commit/?h=debugfs_lookup_fix&id=5167d3e8149e332204274910da1057e8f907d7d2
> 
> Yeah, this is my fault, sorry.  That branch/tree has not been looked at
> carefully in a while, I need to refresh it properly and verify it all is
> correct.  I'll drop this change as part of that work as well, sorry for
> the noise.

No problem, I'm glad to help! :)


Thanks,
SJ

> 
> greg k-h
>