Re: [PATCH v5] module: Add CONFIG_MODULE_DISABLE_INIT_FREE option
From: Dan Carpenter
Date: Fri Oct 27 2023 - 08:00:11 EST
Hi Joey,
kernel test robot noticed the following build warnings:
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Joey-Jiao/module-Add-CONFIG_MODULE_DISABLE_INIT_FREE-option/20231017-115509
base: https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git modules-next
patch link: https://lore.kernel.org/r/20231013062711.28852-1-quic_jiangenj%40quicinc.com
patch subject: [PATCH v5] module: Add CONFIG_MODULE_DISABLE_INIT_FREE option
config: x86_64-randconfig-161-20231026 (https://download.01.org/0day-ci/archive/20231027/202310271751.28pKVu4K-lkp@xxxxxxxxx/config)
compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
reproduce: (https://download.01.org/0day-ci/archive/20231027/202310271751.28pKVu4K-lkp@xxxxxxxxx/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202310271751.28pKVu4K-lkp@xxxxxxxxx/
smatch warnings:
kernel/module/main.c:2608 do_init_module() warn: possible memory leak of 'freeinit'
vim +/freeinit +2608 kernel/module/main.c
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2517
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2518 freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2519 if (!freeinit) {
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2520 ret = -ENOMEM;
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2521 goto fail;
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2522 }
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2523 freeinit->init_text = mod->mem[MOD_INIT_TEXT].base;
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2524 freeinit->init_data = mod->mem[MOD_INIT_DATA].base;
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2525 freeinit->init_rodata = mod->mem[MOD_INIT_RODATA].base;
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2526
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2527 do_mod_ctors(mod);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2528 /* Start the module */
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2529 if (mod->init != NULL)
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2530 ret = do_one_initcall(mod->init);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2531 if (ret < 0) {
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2532 goto fail_free_freeinit;
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2533 }
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2534 if (ret > 0) {
bddb12b32f90c5 kernel/module.c Andrew Morton 2013-11-12 2535 pr_warn("%s: '%s'->init suspiciously returned %d, it should "
bddb12b32f90c5 kernel/module.c Andrew Morton 2013-11-12 2536 "follow 0/-E convention\n"
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2537 "%s: loading module anyway...\n",
bddb12b32f90c5 kernel/module.c Andrew Morton 2013-11-12 2538 __func__, mod->name, ret, __func__);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2539 dump_stack();
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2540 }
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2541
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2542 /* Now it's a first class citizen! */
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2543 mod->state = MODULE_STATE_LIVE;
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2544 blocking_notifier_call_chain(&module_notify_list,
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2545 MODULE_STATE_LIVE, mod);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2546
38dc717e97153e kernel/module.c Jessica Yu 2020-11-27 2547 /* Delay uevent until module has finished its init routine */
38dc717e97153e kernel/module.c Jessica Yu 2020-11-27 2548 kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
38dc717e97153e kernel/module.c Jessica Yu 2020-11-27 2549
774a1221e862b3 kernel/module.c Tejun Heo 2013-01-15 2550 /*
774a1221e862b3 kernel/module.c Tejun Heo 2013-01-15 2551 * We need to finish all async code before the module init sequence
67d6212afda218 kernel/module.c Igor Pylypiv 2022-01-27 2552 * is done. This has potential to deadlock if synchronous module
67d6212afda218 kernel/module.c Igor Pylypiv 2022-01-27 2553 * loading is requested from async (which is not allowed!).
774a1221e862b3 kernel/module.c Tejun Heo 2013-01-15 2554 *
67d6212afda218 kernel/module.c Igor Pylypiv 2022-01-27 2555 * See commit 0fdff3ec6d87 ("async, kmod: warn on synchronous
67d6212afda218 kernel/module.c Igor Pylypiv 2022-01-27 2556 * request_module() from async workers") for more details.
774a1221e862b3 kernel/module.c Tejun Heo 2013-01-15 2557 */
67d6212afda218 kernel/module.c Igor Pylypiv 2022-01-27 2558 if (!mod->async_probe_requested)
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2559 async_synchronize_full();
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2560
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2561 ftrace_free_mem(mod, mod->mem[MOD_INIT_TEXT].base,
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2562 mod->mem[MOD_INIT_TEXT].base + mod->mem[MOD_INIT_TEXT].size);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2563 mutex_lock(&module_mutex);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2564 /* Drop initial reference. */
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2565 module_put(mod);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2566 trim_init_extable(mod);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2567 #ifdef CONFIG_KALLSYMS
8244062ef1e545 kernel/module.c Rusty Russell 2016-02-03 2568 /* Switch to core kallsyms now init is done: kallsyms may be walking! */
8244062ef1e545 kernel/module.c Rusty Russell 2016-02-03 2569 rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2570 #endif
444d13ff10fb13 kernel/module.c Jessica Yu 2016-07-27 2571 module_enable_ro(mod, true);
93c2e105f6bcee kernel/module.c Peter Zijlstra 2015-05-27 2572 mod_tree_remove_init(mod);
d453cded05ee21 kernel/module.c Rusty Russell 2015-01-20 2573 module_arch_freeing_init(mod);
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2574 for_class_mod_mem_type(type, init) {
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2575 mod->mem[type].base = NULL;
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2576 mod->mem[type].size = 0;
ac3b4328392344 kernel/module/main.c Song Liu 2023-02-06 2577 }
df3e764d8e5cd4 kernel/module/main.c Luis Chamberlain 2023-03-28 2578
607c543f939d8c kernel/module.c Andrii Nakryiko 2020-11-20 2579 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
607c543f939d8c kernel/module.c Andrii Nakryiko 2020-11-20 2580 /* .BTF is not SHF_ALLOC and will get removed, so sanitize pointer */
607c543f939d8c kernel/module.c Andrii Nakryiko 2020-11-20 2581 mod->btf_data = NULL;
607c543f939d8c kernel/module.c Andrii Nakryiko 2020-11-20 2582 #endif
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2583 /*
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2584 * We want to free module_init, but be aware that kallsyms may be
0be964be0d4508 kernel/module.c Peter Zijlstra 2015-05-27 2585 * walking this with preempt disabled. In all the failure paths, we
cb2f55369d3a9e kernel/module.c Paul E. McKenney 2018-11-06 2586 * call synchronize_rcu(), but we don't want to slow down the success
1a7b7d9220819a kernel/module.c Rick Edgecombe 2019-04-25 2587 * path. module_memfree() cannot be called in an interrupt, so do the
1a7b7d9220819a kernel/module.c Rick Edgecombe 2019-04-25 2588 * work and call synchronize_rcu() in a work queue.
1a7b7d9220819a kernel/module.c Rick Edgecombe 2019-04-25 2589 *
ae646f0b9ca135 kernel/module.c Jeffrey Hugo 2018-05-11 2590 * Note that module_alloc() on most architectures creates W+X page
ae646f0b9ca135 kernel/module.c Jeffrey Hugo 2018-05-11 2591 * mappings which won't be cleaned up until do_free_init() runs. Any
ae646f0b9ca135 kernel/module.c Jeffrey Hugo 2018-05-11 2592 * code such as mark_rodata_ro() which depends on those mappings to
ae646f0b9ca135 kernel/module.c Jeffrey Hugo 2018-05-11 2593 * be cleaned up needs to sync with the queued work - ie
cb2f55369d3a9e kernel/module.c Paul E. McKenney 2018-11-06 2594 * rcu_barrier()
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2595 */
36022a47582048 kernel/module/main.c Joey Jiao 2023-10-13 2596 if (!IS_ENABLED(CONFIG_MODULE_DISABLE_INIT_FREE) &&
36022a47582048 kernel/module/main.c Joey Jiao 2023-10-13 2597 llist_add(&freeinit->node, &init_free_list))
Let's not allocate freeinit if CONFIG_MODULE_DISABLE_INIT_FREE is not
enabled.
1a7b7d9220819a kernel/module.c Rick Edgecombe 2019-04-25 2598 schedule_work(&init_free_wq);
1a7b7d9220819a kernel/module.c Rick Edgecombe 2019-04-25 2599
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2600 mutex_unlock(&module_mutex);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2601 wake_up_all(&module_wq);
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2602
df3e764d8e5cd4 kernel/module/main.c Luis Chamberlain 2023-03-28 2603 mod_stat_add_long(text_size, &total_text_size);
df3e764d8e5cd4 kernel/module/main.c Luis Chamberlain 2023-03-28 2604 mod_stat_add_long(total_size, &total_mod_size);
df3e764d8e5cd4 kernel/module/main.c Luis Chamberlain 2023-03-28 2605
df3e764d8e5cd4 kernel/module/main.c Luis Chamberlain 2023-03-28 2606 mod_stat_inc(&modcount);
df3e764d8e5cd4 kernel/module/main.c Luis Chamberlain 2023-03-28 2607
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 @2608 return 0;
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2609
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2610 fail_free_freeinit:
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2611 kfree(freeinit);
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2612 fail:
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2613 /* Try to protect us from buggy refcounters. */
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2614 mod->state = MODULE_STATE_GOING;
cb2f55369d3a9e kernel/module.c Paul E. McKenney 2018-11-06 2615 synchronize_rcu();
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2616 module_put(mod);
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2617 blocking_notifier_call_chain(&module_notify_list,
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2618 MODULE_STATE_GOING, mod);
7e545d6eca20ce kernel/module.c Jessica Yu 2016-03-16 2619 klp_module_going(mod);
7dcd182bec271a kernel/module.c Jessica Yu 2016-02-16 2620 ftrace_release_mod(mod);
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2621 free_module(mod);
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2622 wake_up_all(&module_wq);
df3e764d8e5cd4 kernel/module/main.c Luis Chamberlain 2023-03-28 2623
c749637909eea5 kernel/module.c Rusty Russell 2015-01-20 2624 return ret;
34e1169d996ab1 kernel/module.c Kees Cook 2012-10-16 2625 }
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