From 1d6e65bedf5878c8dd5b089d3f034b619bbb8a77 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 7 May 2018 10:54:48 +1000 Subject: [PATCH] staging: lustre: fix error deref in ll_splice_alias(). d_splice_alias() can return an ERR_PTR(). If it does while debugging is enabled, the following CDEBUG() will dereference that error and crash. So add appropriate checking, and provide a separate debug message for the error case. Reported-and-tested-by: James Simmons Fixes: e9d4f0b9f559 ("staging: lustre: llite: use d_splice_alias for directories.") Reviewed-by: James Simmons Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lustre/lustre/llite/namei.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/staging/lustre/lustre/llite/namei.c b/drivers/staging/lustre/lustre/llite/namei.c index 6c9ec462eb41..9ac7f097802d 100644 --- a/drivers/staging/lustre/lustre/llite/namei.c +++ b/drivers/staging/lustre/lustre/llite/namei.c @@ -442,11 +442,16 @@ struct dentry *ll_splice_alias(struct inode *inode, struct dentry *de) } else { struct dentry *new = d_splice_alias(inode, de); + if (IS_ERR(new)) + CDEBUG(D_DENTRY, + "splice inode %p as %pd gives error %lu\n", + inode, de, PTR_ERR(new)); if (new) de = new; } - CDEBUG(D_DENTRY, "Add dentry %p inode %p refc %d flags %#x\n", - de, d_inode(de), d_count(de), de->d_flags); + if (!IS_ERR(de)) + CDEBUG(D_DENTRY, "Add dentry %p inode %p refc %d flags %#x\n", + de, d_inode(de), d_count(de), de->d_flags); return de; } -- 2.30.2