Re: [PATCH] cifs: Fix memory leak on the deferred close

["zhangxiaoxu (A)" <zhangxiaoxu5@xxxxxxxxxx>]

running generic/029 and scan kmemleak on backend report this issue.

在 2022/8/19 0:28, Steve French 写道:
> looks promising - am reviewing this now.  Which xfstest did you see
> this when runnign?
>
> On Thu, Aug 18, 2022 at 8:01 AM Zhang Xiaoxu <zhangxiaoxu5@xxxxxxxxxx> wrote:
> > xfstests on smb21 report kmemleak as below:
> >
> >    unreferenced object 0xffff8881767d6200 (size 64):
> >      comm "xfs_io", pid 1284, jiffies 4294777434 (age 20.789s)
> >      hex dump (first 32 bytes):
> >        80 5a d0 11 81 88 ff ff 78 8a aa 63 81 88 ff ff  .Z......x..c....
> >        00 71 99 76 81 88 ff ff 00 00 00 00 00 00 00 00  .q.v............
> >      backtrace:
> >        [<00000000ad04e6ea>] cifs_close+0x92/0x2c0
> >        [<0000000028b93c82>] __fput+0xff/0x3f0
> >        [<00000000d8116851>] task_work_run+0x85/0xc0
> >        [<0000000027e14f9e>] do_exit+0x5e5/0x1240
> >        [<00000000fb492b95>] do_group_exit+0x58/0xe0
> >        [<00000000129a32d9>] __x64_sys_exit_group+0x28/0x30
> >        [<00000000e3f7d8e9>] do_syscall_64+0x35/0x80
> >        [<00000000102e8a0b>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
> >
> > When cancel the deferred close work, we should also cleanup the struct
> > cifs_deferred_close.
> >
> > Fixes: 9e992755be8f2 ("cifs: Call close synchronously during unlink/rename/lease break.")
> > Fixes: e3fc065682ebb ("cifs: Deferred close performance improvements")
> > Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@xxxxxxxxxx>
> > ---
> >   fs/cifs/misc.c | 6 ++++++
> >   1 file changed, 6 insertions(+)
> >
> > diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> > index 1f2628ffe9d7..87f60f736731 100644
> > --- a/fs/cifs/misc.c
> > +++ b/fs/cifs/misc.c
> > @@ -737,6 +737,8 @@ cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
> >          list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
> >                  if (delayed_work_pending(&cfile->deferred)) {
> >                          if (cancel_delayed_work(&cfile->deferred)) {
> > +                               cifs_del_deferred_close(cfile);
> > +
> >                                  tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
> >                                  if (tmp_list == NULL)
> >                                          break;
> > @@ -766,6 +768,8 @@ cifs_close_all_deferred_files(struct cifs_tcon *tcon)
> >          list_for_each_entry(cfile, &tcon->openFileList, tlist) {
> >                  if (delayed_work_pending(&cfile->deferred)) {
> >                          if (cancel_delayed_work(&cfile->deferred)) {
> > +                               cifs_del_deferred_close(cfile);
> > +
> >                                  tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
> >                                  if (tmp_list == NULL)
> >                                          break;
> > @@ -799,6 +803,8 @@ cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
> >                  if (strstr(full_path, path)) {
> >                          if (delayed_work_pending(&cfile->deferred)) {
> >                                  if (cancel_delayed_work(&cfile->deferred)) {
> > +                                       cifs_del_deferred_close(cfile);
> > +
> >                                          tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
> >                                          if (tmp_list == NULL)
> >                                                  break;
> > --
> > 2.31.1