pstore: Check for prz allocation in walker
Instead of needing additional checks in callers for unallocated przs,
perform the check in the walker, which gives us a more universal way to
handle the situation.
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 1d887ef..11f918d34 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -133,7 +133,8 @@ ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
struct persistent_ram_zone *prz;
int i = (*c)++;
- if (i >= max)
+ /* Give up if we never existed or have hit the end. */
+ if (!przs || i >= max)
return NULL;
prz = przs[i];
@@ -280,7 +281,7 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
1, id, type, PSTORE_TYPE_PMSG, 0);
/* ftrace is last since it may want to dynamically allocate memory. */
- if (!prz_ok(prz) && cxt->fprzs) {
+ if (!prz_ok(prz)) {
if (!(cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)) {
prz = ramoops_get_next_prz(cxt->fprzs,
&cxt->ftrace_read_cnt, 1, id, type,