From: Tejun Heo Date: Fri, 10 Jan 2014 13:57:18 +0000 (-0500) Subject: kernfs: fix get_active failure handling in kernfs_seq_*() X-Git-Tag: v3.14-rc1~151^2~33 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d92d2e6bd72b653f9811e0c9c46307c743b3fc58;p=pandora-kernel.git kernfs: fix get_active failure handling in kernfs_seq_*() When kernfs_seq_start() fails to obtain an active reference, it returns ERR_PTR(-ENODEV). kernfs_seq_stop() is then invoked with the error pointer value; however, it still proceeds to invoke kernfs_put_active() on the node leading to unbalanced put. If kernfs_seq_stop() is called even after active ref failure, it should skip invocation of @ops->seq_stop() and put_active. Unfortunately, this is a bit complicated because active ref failure isn't the only thing which may fail with ERR_PTR(-ENODEV). @ops->seq_start/next() may also fail with the error value and kernfs_seq_stop() doesn't have a way to tell apart those failures. Work it around by factoring out the active part of kernfs_seq_stop() into kernfs_seq_stop_active() and invoking it directly if @ops->seq_start/next() fail with ERR_PTR(-ENODEV) and updating kernfs_seq_stop() to skip kernfs_seq_stop_active() on ERR_PTR(-ENODEV). This is a bit nasty but ensures that the active put is skipped iff get_active failed in kernfs_seq_start(). Signed-off-by: Tejun Heo Cc: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed