[PATCH] xfs: free xfs_busy_extents structure when no RT extents are queued

[PATCH] xfs: free xfs_busy_extents structure when no RT extents are queued

[Christoph Hellwig]

kmemleak occasionally reports leaking xfs_busy_extents structure
from xfs_scrub calls after running xfs/528 (but attributed to following
tests), which seems to be caused by not freeing the xfs_busy_extents
structure when tr.queued is 0 and xfs_trim_rtgroup_extents breaks out
of the main loop.  Free the structure in this case.

Fixes: a3315d11305f ("xfs: use rtgroup busy extent list for FITRIM")
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_discard.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
index ee49f20875af..6917de832191 100644
--- a/fs/xfs/xfs_discard.c
+++ b/fs/xfs/xfs_discard.c
@@ -726,8 +726,10 @@ xfs_trim_rtgroup_extents(
 			break;
 		}
 
-		if (!tr.queued)
+		if (!tr.queued) {
+			kfree(tr.extents);
 			break;
+		}
 
 		/*
 		 * We hand the extent list to the discard function here so the
-- 
2.47.3

Re: [PATCH] xfs: free xfs_busy_extents structure when no RT extents are queued

[Darrick J. Wong]

On Tue, Nov 04, 2025 at 05:43:01AM -0500, Christoph Hellwig wrote:
> kmemleak occasionally reports leaking xfs_busy_extents structure
> from xfs_scrub calls after running xfs/528 (but attributed to following
> tests), which seems to be caused by not freeing the xfs_busy_extents
> structure when tr.queued is 0 and xfs_trim_rtgroup_extents breaks out
> of the main loop.  Free the structure in this case.
> 
> Fixes: a3315d11305f ("xfs: use rtgroup busy extent list for FITRIM")
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Yep, this fixes a memory leak.  I wonder if you could combine the two
into:

	if (error || !tr.queued) {
		kfree(tr.extents);
		break;
	}

But I don't care passionately either way.
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_discard.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c
> index ee49f20875af..6917de832191 100644
> --- a/fs/xfs/xfs_discard.c
> +++ b/fs/xfs/xfs_discard.c
> @@ -726,8 +726,10 @@ xfs_trim_rtgroup_extents(
>  			break;
>  		}
>  
> -		if (!tr.queued)
> +		if (!tr.queued) {
> +			kfree(tr.extents);
>  			break;
> +		}
>  
>  		/*
>  		 * We hand the extent list to the discard function here so the
> -- 
> 2.47.3
> 
> 

Re: [PATCH] xfs: free xfs_busy_extents structure when no RT extents are queued

[Christoph Hellwig]

On Tue, Nov 04, 2025 at 08:59:19AM -0800, Darrick J. Wong wrote:
> Yep, this fixes a memory leak.  I wonder if you could combine the two
> into:
> 
> 	if (error || !tr.queued) {
> 		kfree(tr.extents);
> 		break;
> 	}
> 
> But I don't care passionately either way.
> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

I'd rather keep the fix minimal for now, but yes, otherwise that would
work as well.

Re: [PATCH] xfs: free xfs_busy_extents structure when no RT extents are queued

[Carlos Maiolino]

On Tue, 04 Nov 2025 05:43:01 -0500, Christoph Hellwig wrote:
> kmemleak occasionally reports leaking xfs_busy_extents structure
> from xfs_scrub calls after running xfs/528 (but attributed to following
> tests), which seems to be caused by not freeing the xfs_busy_extents
> structure when tr.queued is 0 and xfs_trim_rtgroup_extents breaks out
> of the main loop.  Free the structure in this case.
> 
> 
> [...]

Applied to for-next, thanks!

[1/1] xfs: free xfs_busy_extents structure when no RT extents are queued
      commit: d8a823c6f04ef03e3bd7249d2e796da903e7238d

Best regards,
-- 
Carlos Maiolino <cem@kernel.org>