Messages in this thread | | | Date | Sun, 2 Mar 2008 15:10:35 +0800 | From | "Peter Teoh" <> | Subject | Unmatched semaphore usage in fs/super.c |
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Please pardon me if wrong. In fs/super.c, I saw a down_read() without a matching (when sb->s_root is non-zero) up_read() as shown below:
/** * get_super - get the superblock of a device * @bdev: device to get the superblock for * * Scans the superblock list and finds the superblock of the file system * mounted on the device given. %NULL is returned if no match is found. */
struct super_block * get_super(struct block_device *bdev) { struct super_block *sb;
if (!bdev) return NULL;
spin_lock(&sb_lock); rescan: list_for_each_entry(sb, &super_blocks, s_list) { if (sb->s_bdev == bdev) { sb->s_count++; spin_unlock(&sb_lock); down_read(&sb->s_umount); if (sb->s_root) return sb; up_read(&sb->s_umount); /* restart only when sb is no longer on the list */ spin_lock(&sb_lock); if (__put_super_and_need_restart(sb)) goto rescan; } } spin_unlock(&sb_lock); return NULL; }
Neither did the get_super() caller remember and correct the semaphore either. Is this a problem?
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