commit c42dd069be8dfc9b2239a5c89e73bbd08ab35de0 upstream. Backporting the patch to stable-v5.10.y to avoid race condition between configfs_dir_lseek and configfs_lookup since they both operate ->s_childre and configfs_lookup forgets to obtain the lock. The patch deviates from the original patch because of code change. The idea is to hold the configfs_dirent_lock when traversing ->s_children, which follows the core idea of the original patch.
Signed-off-by: Kyle Zeng zengyhkyle@gmail.com --- fs/configfs/dir.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index 12388ed4faa5..0b7e9ab517d5 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -479,6 +479,7 @@ static struct dentry * configfs_lookup(struct inode *dir, if (!configfs_dirent_is_ready(parent_sd)) goto out;
+ spin_lock(&configfs_dirent_lock); list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { if (sd->s_type & CONFIGFS_NOT_PINNED) { const unsigned char * name = configfs_get_name(sd); @@ -491,6 +492,7 @@ static struct dentry * configfs_lookup(struct inode *dir, break; } } + spin_unlock(&configfs_dirent_lock);
if (!found) { /*