firmware: stratix10-svc: fix a missing check on list iterator

stable inclusion
from stable-v5.10.122
commit 7027c890ff6b252407256b2019c1f184969c9ab7
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5W6OE

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7027c890ff6b252407256b2019c1f184969c9ab7

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

[ Upstream commit 5a0793ac ]

The bug is here:
	pmem->vaddr = NULL;

The list iterator 'pmem' will point to a bogus position containing
HEAD if the list is empty or no element is found. This case must
be checked before any use of the iterator, otherwise it will
lead to a invalid memory access.

To fix this bug, just gen_pool_free/set NULL/list_del() and return
when found, otherwise list_del HEAD and return;

Fixes: 7ca5ce89 ("firmware: add Intel Stratix10 service layer driver")
Signed-off-by: NXiaomeng Tong <xiam0nd.tong@gmail.com>
Link: https://lore.kernel.org/r/20220414035609.2239-1-xiam0nd.tong@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

drivers/firmware/stratix10-svc.c

@@ -941,17 +941,17 @@ EXPORT_SYMBOL_GPL(stratix10_svc_allocate_memory);
 void stratix10_svc_free_memory(struct stratix10_svc_chan *chan, void *kaddr)
 {
 	struct stratix10_svc_data_mem *pmem;
-	size_t size = 0;
 
 	list_for_each_entry(pmem, &svc_data_mem, node)
 		if (pmem->vaddr == kaddr) {
-			size = pmem->size;
-			break;
-		}
-
-	gen_pool_free(chan->ctrl->genpool, (unsigned long)kaddr, size);
+			gen_pool_free(chan->ctrl->genpool,
+				       (unsigned long)kaddr, pmem->size);
 			pmem->vaddr = NULL;
 			list_del(&pmem->node);
+			return;
+		}
+
+	list_del(&svc_data_mem);
 }
 EXPORT_SYMBOL_GPL(stratix10_svc_free_memory);