From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Layton Subject: Re: [PATCH] ceph: fix memory leak in ceph_cleanup_snapid_map Date: Thu, 19 Mar 2020 10:41:13 -0400 Message-ID: References: <20200319114348.GA72449@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200319114348.GA72449@suse.com> Sender: linux-kernel-owner@vger.kernel.org To: Luis Henriques , Sage Weil , Ilya Dryomov , "Yan, Zheng" Cc: ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: ceph-devel.vger.kernel.org On Thu, 2020-03-19 at 11:43 +0000, Luis Henriques wrote: > kmemleak reports the following memory leak: > > unreferenced object 0xffff88821feac8a0 (size 96): > comm "kworker/1:0", pid 17, jiffies 4294896362 (age 20.512s) > hex dump (first 32 bytes): > a0 c8 ea 1f 82 88 ff ff 00 c9 ea 1f 82 88 ff ff ................ > 00 00 00 00 00 00 00 00 00 01 00 00 00 00 ad de ................ > backtrace: > [<00000000b3ea77fb>] ceph_get_snapid_map+0x75/0x2a0 > [<00000000d4060942>] fill_inode+0xb26/0x1010 > [<0000000049da6206>] ceph_readdir_prepopulate+0x389/0xc40 > [<00000000e2fe2549>] dispatch+0x11ab/0x1521 > [<000000007700b894>] ceph_con_workfn+0xf3d/0x3240 > [<0000000039138a41>] process_one_work+0x24d/0x590 > [<00000000eb751f34>] worker_thread+0x4a/0x3d0 > [<000000007e8f0d42>] kthread+0xfb/0x130 > [<00000000d49bd1fa>] ret_from_fork+0x3a/0x50 > > A kfree was missing in commit 75c9627efb72 ("ceph: map snapid to anonymous > bdev ID"), while looping the 'to_free' list of ceph_snapid_map objects. > > Fixes: 75c9627efb72 ("ceph: map snapid to anonymous bdev ID") > Signed-off-by: Luis Henriques > --- > Hi! > > A bit of mailing-list archaeology shows that v1 of this patch actually > included this kfree [1], and was lost on v2 [2]. > > [1] https://patchwork.kernel.org/patch/10114319/ > [2] https://patchwork.kernel.org/patch/10749907/ > > Cheers, > -- > Luis > > fs/ceph/snap.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c > index ccfcc66aaf44..923be9399b21 100644 > --- a/fs/ceph/snap.c > +++ b/fs/ceph/snap.c > @@ -1155,5 +1155,6 @@ void ceph_cleanup_snapid_map(struct ceph_mds_client *mdsc) > pr_err("snapid map %llx -> %x still in use\n", > sm->snap, sm->dev); > } > + kfree(sm); > } > } Good catch. This looks correct to me. Hmmm...we'll leak one of these for every snapid we encounter. Any objection to marking this for stable? -- Jeff Layton