On 6/7/25 6:16 PM, Petr Pavlu wrote:
> The function move_module() uses the variable t to track how many memory
> types it has allocated and consequently how many should be freed if an
> error occurs.
>
> The variable is initially set to 0 and is updated when a call to
> module_memory_alloc() fails. However, move_module() can fail for other
> reasons as well, in which case t remains set to 0 and no memory is freed.
>
> Fix the problem by setting t to MOD_MEM_NUM_TYPES after all memory types
> have been allocated. Additionally, make the deallocation loop more robust
> by not relying on the mod_mem_type_t enum having a signed integer as its
> underlying type.
>
> Fixes: c7ee8aebf6c0 ("module: add stop-grap sanity check on module memcpy()")
> Signed-off-by: Petr Pavlu <petr.pa...@suse.com>
> ---
> kernel/module/main.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index 08b59c37735e..322b38c0a782 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> [...]
> pr_debug("Final section addresses for %s:\n", mod->name);
> @@ -2693,8 +2694,8 @@ static int move_module(struct module *mod, struct
> load_info *info)
> return 0;
> out_err:
> module_memory_restore_rox(mod);
> - for (t--; t >= 0; t--)
> - module_memory_free(mod, t);
> + for (; t > 0; t--)
> + module_memory_free(mod, t - 1);
> if (codetag_section_found)
> codetag_free_module_sections(mod);
>
This can actually be simply:
while (t--)
module_memory_free(mod, t);
-- Petr
