From: Jan Harkes <jaharkes@xxxxxxxxxx> Subject: coda: avoid NULL pointer dereference from a bad inode Patch series "Coda updates for -next". The following patch series contains some fixes for the Coda kernel module I've had sitting around and were tested extensively in a development version of the Coda kernel module that lives outside of the main kernel. This patch (of 9): Avoid accessing coda_inode_info from a dentry with a bad inode. Link: https://lkml.kernel.org/r/20210908140308.18491-1-jaharkes@xxxxxxxxxx Link: https://lkml.kernel.org/r/20210908140308.18491-2-jaharkes@xxxxxxxxxx Signed-off-by: Jan Harkes <jaharkes@xxxxxxxxxx> Cc: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx> Cc: Jing Yangyang <jing.yangyang@xxxxxxxxxx> Cc: Xin Tan <tanxin.ctf@xxxxxxxxx> Cc: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx> Cc: Zeal Robot <zealci@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/coda/dir.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/fs/coda/dir.c~coda-avoid-null-pointer-dereference-from-a-bad-inode +++ a/fs/coda/dir.c @@ -499,15 +499,20 @@ out: */ static int coda_dentry_delete(const struct dentry * dentry) { - int flags; + struct inode *inode; + struct coda_inode_info *cii; if (d_really_is_negative(dentry)) return 0; - flags = (ITOC(d_inode(dentry))->c_flags) & C_PURGE; - if (is_bad_inode(d_inode(dentry)) || flags) { + inode = d_inode(dentry); + if (!inode || is_bad_inode(inode)) return 1; - } + + cii = ITOC(inode); + if (cii->c_flags & C_PURGE) + return 1; + return 0; } _
