[PATCH AUTOSEL 5.2 038/185] ia64:unwind: fix double free for mod->arch.init_unw_table

Sasha Levin
2019-09-22T18:50:55Z

From: chenzefeng <chenzefeng2@huawei.com>

[ Upstream commit c5e5c48c16422521d363c33cfb0dcf58f88c119b ]

The function free_module in file kernel/module.c as follow:

void free_module(struct module *mod) {
......
module_arch_cleanup(mod);
......
module_arch_freeing_init(mod);
......
}

Both module_arch_cleanup and module_arch_freeing_init function
would free the mod->arch.init_unw_table, which cause double free.

Here, set mod->arch.init_unw_table = NULL after remove the unwind
table to avoid double free.

Signed-off-by: chenzefeng <chenzefeng2@huawei.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/ia64/kernel/module.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c
index 326448f9df160..1a42ba885188a 100644
--- a/arch/ia64/kernel/module.c
+++ b/arch/ia64/kernel/module.c
@@ -914,10 +914,14 @@ module_finalize (const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mo
void
module_arch_cleanup (struct module *mod)
{
- if (mod->arch.init_unw_table)
+ if (mod->arch.init_unw_table) {
unw_remove_unwind_table(mod->arch.init_unw_table);
- if (mod->arch.core_unw_table)
+ mod->arch.init_unw_table = NULL;
+ }
+ if (mod->arch.core_unw_table) {
unw_remove_unwind_table(mod->arch.core_unw_table);
+ mod->arch.core_unw_table = NULL;
+ }
}

void *dereference_module_function_descriptor(struct module *mod, void *ptr)
--
2.20.1