On Fri, Dec 13, 2019 at 7:39 AM Phong Tran tranmanphong@gmail.com wrote:
struct ext4_sb_info.system_blks was marked __rcu. But access the pointer without using RCU lock and dereference. Sparse warning with __rcu notation:
block_validity.c:139:29: warning: incorrect type in argument 1 (different address spaces) block_validity.c:139:29: expected struct rb_root const * block_validity.c:139:29: got struct rb_root [noderef] asn:4 *
Reviewed-by: Jan Kara jack@suse.cz Signed-off-by: Phong Tran tranmanphong@gmail.com
Thanks Phong! Looks like a real bug fix caught thanks to Sparse. So let us mark for stable as well?
- Joel
fs/ext4/block_validity.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
change log: V2: Add Reviewed-by: Jan Kara jack@suse.cz
diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c index d4d4fdfac1a6..1ee04e76bbe0 100644 --- a/fs/ext4/block_validity.c +++ b/fs/ext4/block_validity.c @@ -133,10 +133,13 @@ static void debug_print_tree(struct ext4_sb_info *sbi) { struct rb_node *node; struct ext4_system_zone *entry;
struct ext4_system_blocks *system_blks; int first = 1; printk(KERN_INFO "System zones: ");
node = rb_first(&sbi->system_blks->root);
rcu_read_lock();system_blks = rcu_dereference(sbi->system_blks);node = rb_first(&system_blks->root); while (node) { entry = rb_entry(node, struct ext4_system_zone, node); printk(KERN_CONT "%s%llu-%llu", first ? "" : ", ",@@ -144,6 +147,7 @@ static void debug_print_tree(struct ext4_sb_info *sbi) first = 0; node = rb_next(node); }
rcu_read_unlock(); printk(KERN_CONT "\n");}
-- 2.20.1