On Fri 11-04-25 22:48:40, Zijun Hu wrote:
> On 2025/4/11 22:37, Christian Brauner wrote:
> >> - Potential NULL pointer dereference.
> > I really dislike "potential NULL deref" without an explanation. Please
> > explain how this supposed NULL deref can happen.
> >
>
> okay.
>
> >> Fixes: 31d921c7fb96 ("vfs: Add configuration parser helpers")
> >> Signed-off-by: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
> >> ---
> >> fs/fs_parser.c | 7 +++++--
> >> 1 file changed, 5 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/fs/fs_parser.c b/fs/fs_parser.c
> >> index e635a81e17d965df78ffef27f6885cd70996c6dd..ef7876340a917876bc40df9cdde9232204125a75 100644
> >> --- a/fs/fs_parser.c
> >> +++ b/fs/fs_parser.c
> >> @@ -399,6 +399,9 @@ bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
> >> }
> >>
> >> for (i = 0; i < tbl_size; i++) {
> >> + if (!tbl[i].name && (i + 1 == tbl_size))
> >> + break;
> >> +
> >> if (!tbl[i].name) {
> >> pr_err("VALIDATE C-TBL[%zu]: Null\n", i);
> >> good = false;
> >> @@ -411,13 +414,13 @@ bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
> >> good = false;
> >> }
> >> if (c > 0) {
> >> - pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n",
> >> + pr_err("VALIDATE C-TBL[%zu]: Missorted %s>%s\n",
> >> i, tbl[i-1].name, tbl[i].name);
> >> good = false;
> >> }
> >> }
> >>
> >> - if (tbl[i].value != special &&
> >> + if (tbl[i].name && tbl[i].value != special &&
> >> (tbl[i].value < low || tbl[i].value > high)) {
> >> pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n",
> >> i, tbl[i].name, tbl[i].value, low, high);
>
> for good constant table which ends with empty entry. for original logic,
> when loop reach the last empty entry. above pr_err() may access NULL
> pointer tbl[i].name.
>
>
> i find out this validate_constant_table() also has no callers.
> fix it or remove it ?
Yeah, just drop it. In the kernel we are pretty aggressive in dropping
unused code :)
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
