From d863b50ab01333659314c2034890cb76d9fdc3c7 Mon Sep 17 00:00:00 2001 From: Boaz Harrosh Date: Thu, 10 Feb 2011 15:01:20 -0800 Subject: [PATCH] vfs: call rcu_barrier after ->kill_sb() In commit fa0d7e3de6d6 ("fs: icache RCU free inodes"), we use rcu free inode instead of freeing the inode directly. It causes a crash when we rmmod immediately after we umount the volume[1]. So we need to call rcu_barrier after we kill_sb so that the inode is freed before we do rmmod. The idea is inspired by Aneesh Kumar. rcu_barrier will wait for all callbacks to end before preceding. The original patch was done by Tao Ma, but synchronize_rcu() is not enough here. 1. http://marc.info/?l=linux-fsdevel&m=129680863330185&w=2 Tested-by: Tao Ma Signed-off-by: Boaz Harrosh Cc: Nick Piggin Cc: Al Viro Cc: Chris Mason Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/super.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/super.c b/fs/super.c index 74e149efed8..7e9dd4cc2c0 100644 --- a/fs/super.c +++ b/fs/super.c @@ -177,6 +177,11 @@ void deactivate_locked_super(struct super_block *s) struct file_system_type *fs = s->s_type; if (atomic_dec_and_test(&s->s_active)) { fs->kill_sb(s); + /* + * We need to call rcu_barrier so all the delayed rcu free + * inodes are flushed before we release the fs module. + */ + rcu_barrier(); put_filesystem(fs); put_super(s); } else { -- 2.20.1