[PATCH 6.8 513/715] lib/stackdepot: off by one in depot_fetch_stack()

Sasha Levin
2024-03-24T22:43:26Z

From: Dan Carpenter <dan.carpenter@linaro.org>

[ Upstream commit dc24559472a682eb124e869cb110e7a2fd857322 ]

The stack_pools[] array has DEPOT_MAX_POOLS. The "pools_num" tracks the
number of pools which are initialized. See depot_init_pool() for more
details.

If pool_index == pools_num_cached, this will read one element beyond what
we want. If not all the pools are initialized, then the pool will be
NULL, triggering a WARN(), and if they are all initialized it will read
one element beyond the end of the array.

Link: https://lkml.kernel.org/r/361ac881-60b7-471f-91e5-5bf8fe8042b2@moroto.mountain
Fixes: b29d31885814 ("lib/stackdepot: store free stack records in a freelist")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
lib/stackdepot.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index c043a4186bc59..c1ec2b4b6dabf 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -490,7 +490,7 @@ static struct stack_record *depot_fetch_stack(depot_stack_handle_t handle)

lockdep_assert_not_held(&pool_lock);

- if (pool_index > pools_num_cached) {
+ if (pool_index >= pools_num_cached) {
WARN(1, "pool index %d out of bounds (%d) for stack id %08x\n",
pool_index, pools_num_cached, handle);
return NULL;
--
2.43.0