From a20eb05de3c1cab954d49eb8bb9dc7fe5224caa0 Mon Sep 17 00:00:00 2001
From: Lianbo Jiang <lijiang@redhat.com>
Date: Wed, 5 Jun 2024 17:30:33 +0800
Subject: [PATCH 8/9] Fix for failing to load kernel module

In some kernel modules such as libie.ko, the mem[MOD_TEXT].size
may be zero, currently crash will only check its value to determine
if the module is valid, otherwise it fails to load kernel module with
the following warning and error:

  WARNING: invalid kernel module size: 0
        KERNEL: /lib/modules/6.10.0-rc1+/build/vmlinux
      DUMPFILE: /proc/kcore
          CPUS: 64
          DATE: Wed Jun  5 12:49:02 IDT 2024
        UPTIME: 5 days, 05:57:21
  LOAD AVERAGE: 0.28, 0.06, 0.02
         TASKS: 806
      NODENAME: xxxx
       RELEASE: 6.10.0-rc1+
       VERSION: #1 SMP PREEMPT_DYNAMIC Fri May 31 04:56:59 IDT 2024
       MACHINE: x86_64  (2100 Mhz)
        MEMORY: 1.6 GB
           PID: 203686
       COMMAND: "crash"
          TASK: ffff9f9bf66d0000  [THREAD_INFO: ffff9f9bf66d0000]
           CPU: 52
         STATE: TASK_RUNNING (ACTIVE)

  crash> mod
  mod: cannot access vmalloc'd module memory
  crash>

Lets count the module size to check if the module is valid, that will
avoid the current failure.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
---
 kernel.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/kernel.c b/kernel.c
index cd3d604..8a9d498 100644
--- a/kernel.c
+++ b/kernel.c
@@ -3822,9 +3822,21 @@ module_init(void)
 		case KALLSYMS_V2:
 			if (THIS_KERNEL_VERSION >= LINUX(2,6,27)) {
 				numksyms = UINT(modbuf + OFFSET(module_num_symtab));
-				if (MODULE_MEMORY())
-					/* check mem[MOD_TEXT].size only */
-					size = UINT(modbuf + OFFSET(module_mem) + OFFSET(module_memory_size));
+				if (MODULE_MEMORY()) {
+					/*
+					 * The mem[MOD_TEXT].size may be zero, lets count
+					 * the module size as below.
+					*/
+					int t;
+					size = 0;
+					for_each_mod_mem_type(t) {
+						if (t == MOD_INIT_TEXT)
+							break;
+						size += UINT(modbuf + OFFSET(module_mem) +
+								SIZE(module_memory) * t +
+								OFFSET(module_memory_size));
+					}
+				}
 				else
 					size = UINT(modbuf + MODULE_OFFSET2(module_core_size, rx));
 			} else {
@@ -3927,7 +3939,7 @@ verify_modules(void)
 
                 for (i = 0, found = FALSE; i < kt->mods_installed; i++) {
                         lm = &st->load_modules[i];
-			if (!kvtop(NULL, lm->mod_base, &paddr, 0)) {
+			if (lm->mod_base && !kvtop(NULL, lm->mod_base, &paddr, 0)) {
 				irregularities++;
                                 break;
 			}
-- 
2.40.1