From ed3ad79f87f31beed64778af0b29aff3074f700e Mon Sep 17 00:00:00 2001 From: Fabian Frederick Date: Tue, 17 Feb 2015 13:45:31 -0800 Subject: [PATCH] fs/ufs/super.c: fix potential race condition Let locking subsystem decide on mutex management. As reported by Andrew Morton this patch fixes a bug: : lock_ufs() is assuming that on non-preempt uniprocessor, the calling : code will run atomically up to the matching unlock_ufs(). : : But that isn't true. The very first site I looked at (ufs_frag_map) : does sb_bread() under lock_ufs(). And sb_bread() will call schedule(), : very commonly. : : The ->mutex_owner stuff is a bit hacky but should work OK. Signed-off-by: Fabian Frederick Cc: Evgeniy Dushistov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ufs/super.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/fs/ufs/super.c b/fs/ufs/super.c index e515e99a02f9..8092d3759a5e 100644 --- a/fs/ufs/super.c +++ b/fs/ufs/super.c @@ -95,22 +95,18 @@ void lock_ufs(struct super_block *sb) { -#if defined(CONFIG_SMP) || defined (CONFIG_PREEMPT) struct ufs_sb_info *sbi = UFS_SB(sb); mutex_lock(&sbi->mutex); sbi->mutex_owner = current; -#endif } void unlock_ufs(struct super_block *sb) { -#if defined(CONFIG_SMP) || defined (CONFIG_PREEMPT) struct ufs_sb_info *sbi = UFS_SB(sb); sbi->mutex_owner = NULL; mutex_unlock(&sbi->mutex); -#endif } static struct inode *ufs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation) -- GitLab