| Message ID | 1468283820-25471-1-git-send-email-bo.li.liu@oracle.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 07/11/2016 08:37 PM, Liu Bo wrote: > During build_backref_tree(), if we fail to read a btree node, > we can eventually run into BUG_ON(cache->nr_nodes) that we put > in backref_cache_cleanup(), meaning we have at least one > memory leak. > > This frees the backref_node that we allocate at the very beginning of build_backref_tree(). > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > --- > fs/btrfs/relocation.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > index 0477dca..f00267a 100644 > --- a/fs/btrfs/relocation.c > +++ b/fs/btrfs/relocation.c > @@ -1135,6 +1135,8 @@ out: > btrfs_free_path(path1); > btrfs_free_path(path2); > if (err) { > + int orig_free = 0; > + > while (!list_empty(&useless)) { > lower = list_entry(useless.next, > struct backref_node, list); > @@ -1171,8 +1173,13 @@ out: > lower = list_entry(useless.next, > struct backref_node, list); > list_del_init(&lower->list); > + if (lower == node) > + orig_free = 1; > free_backref_node(cache, lower); > } > + > + if (!orig_free) > + free_backref_node(cache, node); > return ERR_PTR(err); > } > ASSERT(!node || !node->detached); Instead of doing the orig_free set and test ... if (lower == node) node = NULL free_backref_node(cache, lower) } free_backref_node(cache, node); return ERR_PTR(err); Your patch isn't wrong, but having node NULL after it was free'd makes us less likely to make mistakes as the code changes. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Jul 12, 2016 at 11:05:48AM -0400, Chris Mason wrote: > > > On 07/11/2016 08:37 PM, Liu Bo wrote: > > During build_backref_tree(), if we fail to read a btree node, > > we can eventually run into BUG_ON(cache->nr_nodes) that we put > > in backref_cache_cleanup(), meaning we have at least one > > memory leak. > > > > This frees the backref_node that we allocate at the very beginning of build_backref_tree(). > > > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > > --- > > fs/btrfs/relocation.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > > index 0477dca..f00267a 100644 > > --- a/fs/btrfs/relocation.c > > +++ b/fs/btrfs/relocation.c > > @@ -1135,6 +1135,8 @@ out: > > btrfs_free_path(path1); > > btrfs_free_path(path2); > > if (err) { > > + int orig_free = 0; > > + > > while (!list_empty(&useless)) { > > lower = list_entry(useless.next, > > struct backref_node, list); > > @@ -1171,8 +1173,13 @@ out: > > lower = list_entry(useless.next, > > struct backref_node, list); > > list_del_init(&lower->list); > > + if (lower == node) > > + orig_free = 1; > > free_backref_node(cache, lower); > > } > > + > > + if (!orig_free) > > + free_backref_node(cache, node); > > return ERR_PTR(err); > > } > > ASSERT(!node || !node->detached); > > Instead of doing the orig_free set and test > > ... > if (lower == node) > node = NULL > free_backref_node(cache, lower) > } > free_backref_node(cache, node); > return ERR_PTR(err); > > Your patch isn't wrong, but having node NULL after it was free'd makes us > less likely to make mistakes as the code changes. Golden rule indeed. Thanks, -liubo -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 0477dca..f00267a 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -1135,6 +1135,8 @@ out: btrfs_free_path(path1); btrfs_free_path(path2); if (err) { + int orig_free = 0; + while (!list_empty(&useless)) { lower = list_entry(useless.next, struct backref_node, list); @@ -1171,8 +1173,13 @@ out: lower = list_entry(useless.next, struct backref_node, list); list_del_init(&lower->list); + if (lower == node) + orig_free = 1; free_backref_node(cache, lower); } + + if (!orig_free) + free_backref_node(cache, node); return ERR_PTR(err); } ASSERT(!node || !node->detached);
During build_backref_tree(), if we fail to read a btree node, we can eventually run into BUG_ON(cache->nr_nodes) that we put in backref_cache_cleanup(), meaning we have at least one memory leak. This frees the backref_node that we allocate at the very beginning of build_backref_tree(). Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- fs/btrfs/relocation.c | 7 +++++++ 1 file changed, 7 insertions(+)