Hi Lianbo,
I have the patch tested, looks good to me, so ack.
Thanks,
Tao Liu
On Wed, Jun 5, 2024 at 6:06 PM Lianbo Jiang <lijiang@xxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxx>
> ---
> kernel.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/kernel.c b/kernel.c
> index 1728b70c1b5c..e0dc23b9b233 100644
> --- a/kernel.c
> +++ b/kernel.c
> @@ -3821,9 +3821,21 @@ 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 {
> @@ -3926,7 +3938,7 @@ 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;
> }
> --
> 2.45.1
> --
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