Messages in this thread | | | From | Filipe Manana <> | Date | Mon, 20 Apr 2020 18:35:56 +0100 | Subject | Re: [PATCH] btrfs: Fix refcnt leak in btrfs_recover_relocation |
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On Mon, Apr 20, 2020 at 6:34 PM Filipe Manana <fdmanana@gmail.com> wrote: > > On Mon, Apr 20, 2020 at 6:50 AM Xiyu Yang <xiyuyang19@fudan.edu.cn> wrote: > > > > btrfs_recover_relocation() invokes btrfs_join_transaction(), which joins > > a btrfs_trans_handle object into transactions and returns a reference of > > it with increased refcount to "trans". > > > > When btrfs_recover_relocation() returns, "trans" becomes invalid, so the > > refcount should be decreased to keep refcount balanced. > > > > The reference counting issue happens in one exception handling path of > > btrfs_recover_relocation(). When read_fs_root() failed, the refcnt > > increased by btrfs_join_transaction() is not decreased, causing a refcnt > > leak. > > > > Fix this issue by calling btrfs_end_transaction() on this error path > > when read_fs_root() failed. > > > > Fixes: 79787eaab461 ("btrfs: replace many BUG_ONs with proper error > > handling") > > Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> > > Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> > > Reviewed-by: Filipe Manana <fdmanana@suse.com> > > Looks good, thanks.
Btw, the subject could be more clear. Instead of
"btrfs: Fix refcnt leak in btrfs_recover_relocation"
something like
"btrfs: fix transaction leak in ..."
David can probably fixup that when he picks the patch.
Thanks.
> > > --- > > fs/btrfs/relocation.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > > index 995d4b8b1cfd..46a451594c7a 100644 > > --- a/fs/btrfs/relocation.c > > +++ b/fs/btrfs/relocation.c > > @@ -4606,6 +4606,7 @@ int btrfs_recover_relocation(struct btrfs_root *root) > > if (IS_ERR(fs_root)) { > > err = PTR_ERR(fs_root); > > list_add_tail(&reloc_root->root_list, &reloc_roots); > > + btrfs_end_transaction(trans); > > goto out_free; > > } > > > > -- > > 2.7.4 > > > > > -- > Filipe David Manana, > > “Whether you think you can, or you think you can't — you're right.”
-- Filipe David Manana,
“Whether you think you can, or you think you can't — you're right.”
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