Make abd_raidz_gen_iterate() pass an initialized pointer to the callback

Otherwise callbacks may trigger KMSAN violations in the dlen == 0 case.
For example, raidz_syn_pq_abd() will compare an uninitialized pointer
with itself before returning.  This seems harmless, but let's maintain
good hygiene and avoid passing uninitialized variables, if only to
placate KMSAN.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Allan Jude <allan@klarasystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes #15491
This commit is contained in:
Mark Johnston 2023-11-07 13:24:15 -05:00 committed by GitHub
parent 358ce2cf28
commit f4cd1bac72
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1 changed files with 6 additions and 3 deletions

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@ -1025,7 +1025,7 @@ abd_raidz_gen_iterate(abd_t **cabds, abd_t *dabd, size_t off,
size_t len, dlen;
struct abd_iter caiters[3];
struct abd_iter daiter;
void *caddrs[3];
void *caddrs[3], *daddr;
unsigned long flags __maybe_unused = 0;
abd_t *c_cabds[3];
abd_t *c_dabd = NULL;
@ -1057,10 +1057,13 @@ abd_raidz_gen_iterate(abd_t **cabds, abd_t *dabd, size_t off,
if (dsize > 0) {
IMPLY(abd_is_gang(dabd), c_dabd != NULL);
abd_iter_map(&daiter);
daddr = daiter.iter_mapaddr;
len = MIN(daiter.iter_mapsize, len);
dlen = len;
} else
} else {
daddr = NULL;
dlen = 0;
}
/* must be progressive */
ASSERT3U(len, >, 0);
@ -1070,7 +1073,7 @@ abd_raidz_gen_iterate(abd_t **cabds, abd_t *dabd, size_t off,
*/
ASSERT3U(((uint64_t)len & 511ULL), ==, 0);
func_raidz_gen(caddrs, daiter.iter_mapaddr, len, dlen);
func_raidz_gen(caddrs, daddr, len, dlen);
for (i = parity-1; i >= 0; i--) {
abd_iter_unmap(&caiters[i]);