Hi, On 24/03/15 02:36, Chengyu Song wrote:
debugfs_create_dir and debugfs_create_file may return -ENODEV when debugfs is not configured, so the return value should be checked against ERROR_VALUE as well, otherwise the later dereference of the dentry pointer would crash the kernel.
Looks reasonable to me:
Acked-by: Steven Whitehouse <swhit...@redhat.com> Steve.
Signed-off-by: Chengyu Song <cson...@gatech.edu> --- fs/gfs2/glock.c | 47 ++++++++++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 19 deletions(-) diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index f42dffb..0fa8062 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -2047,34 +2047,41 @@ static const struct file_operations gfs2_sbstats_fops = {int gfs2_create_debugfs_file(struct gfs2_sbd *sdp){ - sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root); - if (!sdp->debugfs_dir) - return -ENOMEM; - sdp->debugfs_dentry_glocks = debugfs_create_file("glocks", - S_IFREG | S_IRUGO, - sdp->debugfs_dir, sdp, - &gfs2_glocks_fops); - if (!sdp->debugfs_dentry_glocks) + struct dentry *dent; + + dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root); + if (IS_ERR_OR_NULL(dent)) + goto fail; + sdp->debugfs_dir = dent; + + dent = debugfs_create_file("glocks", + S_IFREG | S_IRUGO, + sdp->debugfs_dir, sdp, + &gfs2_glocks_fops); + if (IS_ERR_OR_NULL(dent)) goto fail; + sdp->debugfs_dentry_glocks = dent;- sdp->debugfs_dentry_glstats = debugfs_create_file("glstats",- S_IFREG | S_IRUGO, - sdp->debugfs_dir, sdp, - &gfs2_glstats_fops); - if (!sdp->debugfs_dentry_glstats) + dent = debugfs_create_file("glstats", + S_IFREG | S_IRUGO, + sdp->debugfs_dir, sdp, + &gfs2_glstats_fops); + if (IS_ERR_OR_NULL(dent)) goto fail; + sdp->debugfs_dentry_glstats = dent;- sdp->debugfs_dentry_sbstats = debugfs_create_file("sbstats",- S_IFREG | S_IRUGO, - sdp->debugfs_dir, sdp, - &gfs2_sbstats_fops); - if (!sdp->debugfs_dentry_sbstats) + dent = debugfs_create_file("sbstats", + S_IFREG | S_IRUGO, + sdp->debugfs_dir, sdp, + &gfs2_sbstats_fops); + if (IS_ERR_OR_NULL(dent)) goto fail; + sdp->debugfs_dentry_sbstats = dent;return 0;fail: gfs2_delete_debugfs_file(sdp); - return -ENOMEM; + return dent ? PTR_ERR(dent) : -ENOMEM; }void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)@@ -2100,6 +2107,8 @@ void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp) int gfs2_register_debugfs(void) { gfs2_root = debugfs_create_dir("gfs2", NULL); + if (IS_ERR(gfs2_root)) + return PTR_ERR(gfs2_root); return gfs2_root ? 0 : -ENOMEM; }
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