On Mon, Jun 3, 2024 at 5:33 AM Geunsik Lim <geunsik.lim@xxxxxxxxx> wrote: > > This commit addresses a potential memory leak in the > `get_mm_memcg_path()` function > by explicitly checking if the allocated buffer (`buf`) is NULL before > calling the > `css_put()` function. The prefix 'css' means abbreviation of cgroup_subsys_state > > Previously, the code would directly call `css_put()` without checking > the value of > `buf`, which could lead to a memory leak if the buffer allocation failed. > This commit introduces a conditional check to ensure that `css_put()` > is only called > if `buf` is not NULL. > > This change enhances the code's robustness and prevents memory leaks, improving > overall system stability. > > **Specific Changes:** > > * In the `out_put` label, an `if` statement is added to check > if `buf` is not NULL before calling `css_put()`. > > **Benefits:** > > * Prevents potential memory leaks > * Enhances code robustness > * Improves system stability > > Signed-off-by: Geunsik Lim <leemgs@xxxxxxxxx> > Signed-off-by: Geunsik Lim <geunsik.lim@xxxxxxxxxxx> > --- > mm/mmap_lock.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c > index 1854850b4b89..7314045b0e3b 100644 > --- a/mm/mmap_lock.c > +++ b/mm/mmap_lock.c > @@ -213,7 +213,8 @@ static const char *get_mm_memcg_path(struct mm_struct *mm) > cgroup_path(memcg->css.cgroup, buf, MEMCG_PATH_BUF_SIZE); > > out_put: > - css_put(&memcg->css); > + if (buf != NULL) > + css_put(&memcg->css); > out: > return buf; > } I think the existing code is correct, and this change actually introduces a memory leak where there was none before. In the case where get_memcg_path_buf() returns NULL, we *still* need to css_put() what we got from get_mem_cgroup_from_mm() before. NAK, unless I'm missing something. > -- > 2.34.1 > ---- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
