Messages in this thread | | | Subject | Re: [PATCH] ceph: fix memory leak in mount error path when using test_dummy_encryption | From | Xiubo Li <> | Date | Tue, 8 Nov 2022 13:56:50 +0800 |
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On 07/11/2022 22:19, Luís Henriques wrote: > On Mon, Nov 07, 2022 at 07:06:40PM +0800, Xiubo Li wrote: >> On 07/11/2022 18:23, Luís Henriques wrote: >>> On Mon, Nov 07, 2022 at 03:47:23PM +0800, Xiubo Li wrote: >>>> On 03/11/2022 23:36, Luís Henriques wrote: >>>>> Because ceph_init_fs_context() will never be invoced in case we get a >>>>> mount error, destroy_mount_options() won't be releasing fscrypt resources >>>>> with fscrypt_free_dummy_policy(). This will result in a memory leak. Add >>>>> an invocation to this function in the mount error path. >>>>> >>>>> Signed-off-by: Luís Henriques <lhenriques@suse.de> >>>>> --- >>>>> fs/ceph/super.c | 1 + >>>>> 1 file changed, 1 insertion(+) >>>>> >>>>> diff --git a/fs/ceph/super.c b/fs/ceph/super.c >>>>> index 2224d44d21c0..6b9fd04b25cd 100644 >>>>> --- a/fs/ceph/super.c >>>>> +++ b/fs/ceph/super.c >>>>> @@ -1362,6 +1362,7 @@ static int ceph_get_tree(struct fs_context *fc) >>>>> ceph_mdsc_close_sessions(fsc->mdsc); >>>>> deactivate_locked_super(sb); >>>>> + fscrypt_free_dummy_policy(&fsc->fsc_dummy_enc_policy); >>>> Hi Luis, >>>> >>>> BTW, any reason the following code won't be triggered ? >>>> >>>> deactivate_locked_super(sb); >>>> >>>> --> fs->kill_sb(s); >>>> >>>> --> ceph_kill_sb() >>>> >>>> --> kill_anon_super() >>>> >>>> --> generic_shutdown_super() >>>> >>>> --> sop->put_super() >>>> >>>> --> ceph_put_super() >>>> >>>> --> ceph_fscrypt_free_dummy_policy() >>>> >>>> --> fscrypt_free_dummy_policy( >>>> >>> Here's what I'm seeing here: >>> >>> sys_mount->path_mount->do_new_mount->vfs_get_tree->ceph_get_tree >>> >>> ceph_get_tree() fails due to ceph_real_mount() returning an error. My >>> understanding is that that, since fc->root is never set, that code path >>> will never be triggered. Does that make sense? >> Okay, you are right! >> >> How about fixing it in ceph_real_mount() instead ? > Sure, I can send a patch for doing that instead. However, my opinion is > that it makes more sense to do it, mostly because ceph_get_tree() is > already doing clean-up work on the error path (ceph_mdsc_close_sessions() > and deactivate_locked_super()). > > But let me know if you really prefer doing in ceph_read_mount() and I'll > send v2.
IMO it'd better to do this in ceph_real_mount(), which will make the code to be easier to read.
Thanks!
- Xiubo
>>> An easy way to reproduce is by running fstest ceph/005 with the >>> 'test_dummy_encryption' option. (I'll probably need to send a patch to >>> disable this test when this option is present.) >> Anyway this should be fixed in kceph. > Yes, agreed. > > Cheers, > -- > Luís >
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