drm/amdkfd: Check for potential null return of kmalloc_array()

stable inclusion
from stable-v5.10.112
commit 1d7a5aae884ca727d41c7ed15d4c82fdb67c040c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5HL0X

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1d7a5aae884ca727d41c7ed15d4c82fdb67c040c

--------------------------------

[ Upstream commit ebbb7bb9 ]

As the kmalloc_array() may return null, the 'event_waiters[i].wait' would lead to null-pointer dereference.
Therefore, it is better to check the return value of kmalloc_array() to avoid this confusion.
Signed-off-by: NQintaoShen <unSimple1993@163.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/gpu/drm/amd/amdkfd/kfd_events.c

@@ -531,6 +531,8 @@ static struct kfd_event_waiter *alloc_event_waiters(uint32_t num_events)
 	event_waiters = kmalloc_array(num_events,
 					sizeof(struct kfd_event_waiter),
 					GFP_KERNEL);
+	if (!event_waiters)
+		return NULL;
 
 	for (i = 0; (event_waiters) && (i < num_events) ; i++) {
 		init_wait(&event_waiters[i].wait);