* [PATCH v2] mm/damon/dbgfs: fix memory leak when using
@ 2022-09-02 19:11 SeongJae Park
2022-09-03 5:36 ` Greg KH
0 siblings, 1 reply; 2+ messages in thread
From: SeongJae Park @ 2022-09-02 19:11 UTC (permalink / raw)
To: akpm; +Cc: sj, gregkh, damon, linux-mm, linux-kernel, stable
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
debugfs_lookup()
Date: Fri, 2 Sep 2022 14:56:31 +0200 [thread overview]
Message-ID: <20220902125631.128329-1-gregkh@linuxfoundation.org> (raw)
When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. Fix this up by properly
calling dput().
Fixes: 75c1c2b53c78b ("mm/damon/dbgfs: support multiple contexts")
Cc: <stable@vger.kernel.org> # 5.15.x
Cc: SeongJae Park <sj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: damon@lists.linux.dev
Cc: linux-mm@kvack.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
---
Changes from v1
(https://lore.kernel.org/damon/20220902125631.128329-1-gregkh@linuxfoundation.org/)
- Call dput() for failure-return case (Andrew Morton)
mm/damon/dbgfs.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 3b55a1b219b5..652a94deafe3 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -884,6 +884,7 @@ static int dbgfs_rm_context(char *name)
struct dentry *root, *dir, **new_dirs;
struct damon_ctx **new_ctxs;
int i, j;
+ int ret = 0;
if (damon_nr_running_ctxs())
return -EBUSY;
@@ -898,14 +899,16 @@ static int dbgfs_rm_context(char *name)
new_dirs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_dirs),
GFP_KERNEL);
- if (!new_dirs)
- return -ENOMEM;
+ if (!new_dirs) {
+ ret = -ENOMEM;
+ goto out_dput;
+ }
new_ctxs = kmalloc_array(dbgfs_nr_ctxs - 1, sizeof(*dbgfs_ctxs),
GFP_KERNEL);
if (!new_ctxs) {
- kfree(new_dirs);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto out_new_dirs;
}
for (i = 0, j = 0; i < dbgfs_nr_ctxs; i++) {
@@ -925,7 +928,13 @@ static int dbgfs_rm_context(char *name)
dbgfs_ctxs = new_ctxs;
dbgfs_nr_ctxs--;
- return 0;
+ goto out_dput;
+
+out_new_dirs:
+ kfree(new_dirs);
+out_dput:
+ dput(dir);
+ return ret;
}
static ssize_t dbgfs_rm_context_write(struct file *file,
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] mm/damon/dbgfs: fix memory leak when using
2022-09-02 19:11 [PATCH v2] mm/damon/dbgfs: fix memory leak when using SeongJae Park
@ 2022-09-03 5:36 ` Greg KH
0 siblings, 0 replies; 2+ messages in thread
From: Greg KH @ 2022-09-03 5:36 UTC (permalink / raw)
To: SeongJae Park; +Cc: akpm, damon, linux-mm, linux-kernel, stable
On Fri, Sep 02, 2022 at 07:11:49PM +0000, SeongJae Park wrote:
> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> debugfs_lookup()
> Date: Fri, 2 Sep 2022 14:56:31 +0200 [thread overview]
> Message-ID: <20220902125631.128329-1-gregkh@linuxfoundation.org> (raw)
>
> When calling debugfs_lookup() the result must have dput() called on it,
> otherwise the memory will leak over time. Fix this up by properly
> calling dput().
>
> Fixes: 75c1c2b53c78b ("mm/damon/dbgfs: support multiple contexts")
> Cc: <stable@vger.kernel.org> # 5.15.x
> Cc: SeongJae Park <sj@kernel.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: damon@lists.linux.dev
> Cc: linux-mm@kvack.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: SeongJae Park <sj@kernel.org>
> ---
> Changes from v1
> (https://lore.kernel.org/damon/20220902125631.128329-1-gregkh@linuxfoundation.org/)
> - Call dput() for failure-return case (Andrew Morton)
Thanks for fixing this up, I missed the other return error cases in my
rush to audit the whole tree at once.
This version looks great, and I see Andrew has taken it now into his
tree, thanks!
greg k-h
^ permalink raw reply [flat|nested] 2+ messages in thread
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