Messages in this thread Patch in this message | | | From | chenzefeng <> | Subject | [PATCH] arm:unwind: fix incorrect backtrace with unwind_table | Date | Wed, 18 Sep 2019 11:09:34 +0800 |
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For arm, if the CONFIG_ARM_UNWIND is open, when insmod a module, the init section add to the unwind_table, the code path as follow: load_module --->post_relocation ------->module_finalize ----------->maps[ARM_SEC_INIT].txt_sec = s ----------->unwind_table_add
Later if load_module success, the init section's memory will be vfree, the code path as follow: load_module --->do_init_module ------->freeinit->module_init = mod->init_layout.base ------->schedule_work(&init_free_wq) ----------->do_free_init --------------->vfree(freeinit->module_init)
But after the init section's had been vfree, but it's unwind_table is not removed.
The issue as follow: When insmod module A, the system alloc the "Addr1" for it's init text section, and add it to the unwind_table list, after insmod success, the "Addr1" would be vfreed. Unfortunately, later insmod module B, the system alloc the "Addr1" for it's text section, and add it to the unwind_table list, too. And we dumpstack in module B, we may get a incorrect backtrace.
Signed-off-by: chenzefeng <chenzefeng2@huawei.com> --- arch/arm/kernel/module.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c index deef17f..438ed67 100644 --- a/arch/arm/kernel/module.c +++ b/arch/arm/kernel/module.c @@ -410,7 +410,20 @@ int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, int i; for (i = 0; i < ARM_SEC_MAX; i++) - if (mod->arch.unwind[i]) + if (mod->arch.unwind[i]) { unwind_table_del(mod->arch.unwind[i]); + mod->arch.unwind[i] = NULL; + } +#endif +} + +void +module_arch_freeing_init(struct module *mod) +{ +#ifdef CONFIG_ARM_UNWIND + if (mod->arch.unwind[ARM_SEC_INIT]) { + unwind_table_del(mod->arch.unwind[ARM_SEC_INIT]); + mod->arch.unwind[ARM_SEC_INIT] = NULL; + } #endif } -- 1.8.5.6
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