Messages in this thread Patch in this message | | | From | NeilBrown <> | Date | Mon, 07 May 2018 10:54:48 +1000 | Subject | [PATCH 10/10] staging: lustre: fix error deref in ll_splice_alias(). |
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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 <jsimmons@infradead.org> Fixes: e9d4f0b9f559 ("staging: lustre: llite: use d_splice_alias for directories.") Reviewed-by: James Simmons <jsimmons@infradead.org> Signed-off-by: NeilBrown <neilb@suse.com> --- 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; }
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