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Date: Thu, 5 Jan 2023 10:53:57 +0100
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: SeongJae Park <sj@kernel.org>
Cc: kernel test robot <oliver.sang@intel.com>, devel@driverdev.osuosl.org,
	damon@lists.linux.dev, linux-mm@kvack.org, oe-lkp@lists.linux.dev,
	Andrew Morton <akpm@linux-foundation.org>,
	stable <stable@kernel.org>
Subject: Re: [driver-core:debugfs_lookup_fix] [mm/damon/dbgfs] ff25f87cfc:
 kernel_BUG_at_lib/list_debug.c
Message-ID: <Y7aeNRf3TyTufC8L@kroah.com>
References: <202301031611.c49a0c74-oliver.sang@intel.com>
 <20230104183539.1509-1-sj@kernel.org>
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In-Reply-To: <20230104183539.1509-1-sj@kernel.org>

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.

greg k-h