From: Li Huafei <lihuafei1@huawei.com> hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5CJ7X -------------------------------- Currently, arch_klp_code_modify_{prepare, post_process} is implemented only in the x86 architecture. It is used to hold the 'text_mutex' lock before entering the stop_machine and modifying the code, and to release the lock after exiting the stop_machine. klp_mem_prepare() needs to hold the 'text_mutex' lock only when saving old instruction code on x86 to ensure that it holds valid instructions. Place klp_mem_prepare() before arch_klp_code_modify_prepare() and lock the save instruction action separately to narrow the 'text_mutex' lock. Signed-off-by: Li Huafei <lihuafei1@huawei.com> Reviewed-by: Xu Kuohai <xukuohai@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- arch/x86/kernel/livepatch.c | 11 +++++++++-- kernel/livepatch/core.c | 6 ++---- 2 files changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/livepatch.c b/arch/x86/kernel/livepatch.c index fe34183826d3..0a2ba5c8ba4e 100644 --- a/arch/x86/kernel/livepatch.c +++ b/arch/x86/kernel/livepatch.c @@ -386,8 +386,15 @@ void arch_klp_code_modify_post_process(void) long arch_klp_save_old_code(struct arch_klp_data *arch_data, void *old_func) { - return copy_from_kernel_nofault(arch_data->old_code, - old_func, JMP_E9_INSN_SIZE); + long ret; + + /* Prevent text modification */ + mutex_lock(&text_mutex); + ret = copy_from_kernel_nofault(arch_data->old_code, + old_func, JMP_E9_INSN_SIZE); + mutex_unlock(&text_mutex); + + return ret; } int arch_klp_patch_func(struct klp_func *func) diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 4d79543d9155..957f16f6c6c4 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -1696,12 +1696,10 @@ static int __klp_enable_patch(struct klp_patch *patch) } #endif - arch_klp_code_modify_prepare(); ret = klp_mem_prepare(patch); - if (ret) { - arch_klp_code_modify_post_process(); + if (ret) return ret; - } + arch_klp_code_modify_prepare(); ret = stop_machine(klp_try_enable_patch, &patch_data, cpu_online_mask); arch_klp_code_modify_post_process(); if (ret) { -- 2.20.1