From 7cb14ba75d57910cc4b62115dd5db7bd83c93684 Mon Sep 17 00:00:00 2001 From: Andreas Robinson Date: Tue, 20 Aug 2013 15:33:19 +0930 Subject: modules: add support for soft module dependencies Additional and optional dependencies not found while building the kernel and modules, can now be declared explicitly. Signed-off-by: Andreas Robinson Acked-by: Herbert Xu Signed-off-by: Rusty Russell --- include/linux/module.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include') diff --git a/include/linux/module.h b/include/linux/module.h index 46f1ea01e6f6..504035f3ece1 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -97,6 +97,11 @@ extern const struct gtype##_id __mod_##gtype##_table \ /* For userspace: you can also call me... */ #define MODULE_ALIAS(_alias) MODULE_INFO(alias, _alias) +/* Soft module dependencies. See man modprobe.d for details. + * Example: MODULE_SOFTDEP("pre: module-foo module-bar post: module-baz") + */ +#define MODULE_SOFTDEP(_softdep) MODULE_INFO(softdep, _softdep) + /* * The following license idents are currently accepted as indicating free * software modules -- cgit v1.2.3 From ab013c5f60b7ead254863c75b9adc2a47992d01b Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 20 Aug 2013 15:33:19 +0930 Subject: module: Add flag to allow mod params to have no arguments Currently the params.c code allows only two "set" functions to have no arguments. If a parameter does not have an argument, then it looks at the set function and tests if it is either param_set_bool() or param_set_bint(). If it is not one of these functions, then it fails the loading of the module. But there may be module parameters that have different set functions and still allow no arguments. But unless each of these cases adds their function to the if statement, it wont be allowed to have no arguments. This method gets rather messing and does not scale. Instead, introduce a flags field to the kernel_param_ops, where if the flag KERNEL_PARAM_FL_NOARG is set, the parameter will not fail if it does not contain an argument. It will be expected that the corresponding set function can handle a NULL pointer as "val". Signed-off-by: Steven Rostedt Signed-off-by: Rusty Russell --- include/linux/moduleparam.h | 13 ++++++++++++- kernel/params.c | 6 ++++-- 2 files changed, 16 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 27d9da3f86ff..c3eb102a9cc8 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -36,7 +36,18 @@ static const char __UNIQUE_ID(name)[] \ struct kernel_param; +/* + * Flags available for kernel_param_ops + * + * NOARG - the parameter allows for no argument (foo instead of foo=1) + */ +enum { + KERNEL_PARAM_FL_NOARG = (1 << 0) +}; + struct kernel_param_ops { + /* How the ops should behave */ + unsigned int flags; /* Returns 0, or -errno. arg is in kp->arg. */ int (*set)(const char *val, const struct kernel_param *kp); /* Returns length written or -errno. Buffer is 4k (ie. be short!) */ @@ -187,7 +198,7 @@ struct kparam_array /* Obsolete - use module_param_cb() */ #define module_param_call(name, set, get, arg, perm) \ static struct kernel_param_ops __param_ops_##name = \ - { (void *)set, (void *)get }; \ + { 0, (void *)set, (void *)get }; \ __module_param_call(MODULE_PARAM_PREFIX, \ name, &__param_ops_##name, arg, \ (perm) + sizeof(__check_old_set_param(set))*0, -1) diff --git a/kernel/params.c b/kernel/params.c index 59f7ac7bec04..ec4299cfade8 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -103,8 +103,8 @@ static int parse_one(char *param, || params[i].level > max_level) return 0; /* No one handled NULL, so do it here. */ - if (!val && params[i].ops->set != param_set_bool - && params[i].ops->set != param_set_bint) + if (!val && + !(params[i].ops->flags & KERNEL_PARAM_FL_NOARG)) return -EINVAL; pr_debug("handling %s with %p\n", param, params[i].ops->set); @@ -320,6 +320,7 @@ int param_get_bool(char *buffer, const struct kernel_param *kp) EXPORT_SYMBOL(param_get_bool); struct kernel_param_ops param_ops_bool = { + .flags = KERNEL_PARAM_FL_NOARG, .set = param_set_bool, .get = param_get_bool, }; @@ -370,6 +371,7 @@ int param_set_bint(const char *val, const struct kernel_param *kp) EXPORT_SYMBOL(param_set_bint); struct kernel_param_ops param_ops_bint = { + .flags = KERNEL_PARAM_FL_NOARG, .set = param_set_bint, .get = param_get_int, }; -- cgit v1.2.3 From 942e443127e928a5631c3d5102aca8c8b3c2dd98 Mon Sep 17 00:00:00 2001 From: Li Zhong Date: Tue, 3 Sep 2013 16:33:57 +0930 Subject: module: Fix mod->mkobj.kobj potentially freed too early DEBUG_KOBJECT_RELEASE helps to find the issue attached below. After some investigation, it seems the reason is: The mod->mkobj.kobj(ffffffffa01600d0 below) is freed together with mod itself in free_module(). However, its children still hold references to it, as the delay caused by DEBUG_KOBJECT_RELEASE. So when the child(holders below) tries to decrease the reference count to its parent in kobject_del(), BUG happens as it tries to access already freed memory. This patch tries to fix it by waiting for the mod->mkobj.kobj to be really released in the module removing process (and some error code paths). [ 1844.175287] kobject: 'holders' (ffff88007c1f1600): kobject_release, parent ffffffffa01600d0 (delayed) [ 1844.178991] kobject: 'notes' (ffff8800370b2a00): kobject_release, parent ffffffffa01600d0 (delayed) [ 1845.180118] kobject: 'holders' (ffff88007c1f1600): kobject_cleanup, parent ffffffffa01600d0 [ 1845.182130] kobject: 'holders' (ffff88007c1f1600): auto cleanup kobject_del [ 1845.184120] BUG: unable to handle kernel paging request at ffffffffa01601d0 [ 1845.185026] IP: [] kobject_put+0x11/0x60 [ 1845.185026] PGD 1a13067 PUD 1a14063 PMD 7bd30067 PTE 0 [ 1845.185026] Oops: 0000 [#1] PREEMPT [ 1845.185026] Modules linked in: xfs libcrc32c [last unloaded: kprobe_example] [ 1845.185026] CPU: 0 PID: 18 Comm: kworker/0:1 Tainted: G O 3.11.0-rc6-next-20130819+ #1 [ 1845.185026] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 1845.185026] Workqueue: events kobject_delayed_cleanup [ 1845.185026] task: ffff88007ca51f00 ti: ffff88007ca5c000 task.ti: ffff88007ca5c000 [ 1845.185026] RIP: 0010:[] [] kobject_put+0x11/0x60 [ 1845.185026] RSP: 0018:ffff88007ca5dd08 EFLAGS: 00010282 [ 1845.185026] RAX: 0000000000002000 RBX: ffffffffa01600d0 RCX: ffffffff8177d638 [ 1845.185026] RDX: ffff88007ca5dc18 RSI: 0000000000000000 RDI: ffffffffa01600d0 [ 1845.185026] RBP: ffff88007ca5dd18 R08: ffffffff824e9810 R09: ffffffffffffffff [ 1845.185026] R10: ffff8800ffffffff R11: dead4ead00000001 R12: ffffffff81a95040 [ 1845.185026] R13: ffff88007b27a960 R14: ffff88007c1f1600 R15: 0000000000000000 [ 1845.185026] FS: 0000000000000000(0000) GS:ffffffff81a23000(0000) knlGS:0000000000000000 [ 1845.185026] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 1845.185026] CR2: ffffffffa01601d0 CR3: 0000000037207000 CR4: 00000000000006b0 [ 1845.185026] Stack: [ 1845.185026] ffff88007c1f1600 ffff88007c1f1600 ffff88007ca5dd38 ffffffff812cdb7e [ 1845.185026] 0000000000000000 ffff88007c1f1640 ffff88007ca5dd68 ffffffff812cdbfe [ 1845.185026] ffff88007c974800 ffff88007c1f1640 ffff88007ff61a00 0000000000000000 [ 1845.185026] Call Trace: [ 1845.185026] [] kobject_del+0x2e/0x40 [ 1845.185026] [] kobject_delayed_cleanup+0x6e/0x1d0 [ 1845.185026] [] process_one_work+0x1e5/0x670 [ 1845.185026] [] ? process_one_work+0x183/0x670 [ 1845.185026] [] worker_thread+0x113/0x370 [ 1845.185026] [] ? rescuer_thread+0x290/0x290 [ 1845.185026] [] kthread+0xda/0xe0 [ 1845.185026] [] ? _raw_spin_unlock_irq+0x30/0x60 [ 1845.185026] [] ? kthread_create_on_node+0x130/0x130 [ 1845.185026] [] ret_from_fork+0x7a/0xb0 [ 1845.185026] [] ? kthread_create_on_node+0x130/0x130 [ 1845.185026] Code: 81 48 c7 c7 28 95 ad 81 31 c0 e8 9b da 01 00 e9 4f ff ff ff 66 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb 48 83 ec 08 48 85 ff 74 1d 87 00 01 00 00 01 74 1e 48 8d 7b 38 83 6b 38 01 0f 94 c0 84 [ 1845.185026] RIP [] kobject_put+0x11/0x60 [ 1845.185026] RSP [ 1845.185026] CR2: ffffffffa01601d0 [ 1845.185026] ---[ end trace 49a70afd109f5653 ]--- Signed-off-by: Li Zhong Acked-by: Greg Kroah-Hartman Signed-off-by: Rusty Russell --- include/linux/module.h | 1 + kernel/module.c | 14 +++++++++++--- kernel/params.c | 7 +++++++ 3 files changed, 19 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/module.h b/include/linux/module.h index 504035f3ece1..05f2447f8c15 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -42,6 +42,7 @@ struct module_kobject { struct module *mod; struct kobject *drivers_dir; struct module_param_attrs *mp; + struct completion *kobj_completion; }; struct module_attribute { diff --git a/kernel/module.c b/kernel/module.c index 40ee1dc3c3bf..9f5ddae72f44 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1612,6 +1612,14 @@ static void module_remove_modinfo_attrs(struct module *mod) kfree(mod->modinfo_attrs); } +static void mod_kobject_put(struct module *mod) +{ + DECLARE_COMPLETION_ONSTACK(c); + mod->mkobj.kobj_completion = &c; + kobject_put(&mod->mkobj.kobj); + wait_for_completion(&c); +} + static int mod_sysfs_init(struct module *mod) { int err; @@ -1639,7 +1647,7 @@ static int mod_sysfs_init(struct module *mod) err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL, "%s", mod->name); if (err) - kobject_put(&mod->mkobj.kobj); + mod_kobject_put(mod); /* delay uevent until full sysfs population */ out: @@ -1683,7 +1691,7 @@ out_unreg_param: out_unreg_holders: kobject_put(mod->holders_dir); out_unreg: - kobject_put(&mod->mkobj.kobj); + mod_kobject_put(mod); out: return err; } @@ -1692,7 +1700,7 @@ static void mod_sysfs_fini(struct module *mod) { remove_notes_attrs(mod); remove_sect_attrs(mod); - kobject_put(&mod->mkobj.kobj); + mod_kobject_put(mod); } #else /* !CONFIG_SYSFS */ diff --git a/kernel/params.c b/kernel/params.c index e5f8f17e57cf..501bde4f3bee 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -915,7 +915,14 @@ static const struct kset_uevent_ops module_uevent_ops = { struct kset *module_kset; int module_sysfs_initialized; +static void module_kobj_release(struct kobject *kobj) +{ + struct module_kobject *mk = to_module_kobject(kobj); + complete(mk->kobj_completion); +} + struct kobj_type module_ktype = { + .release = module_kobj_release, .sysfs_ops = &module_sysfs_ops, }; -- cgit v1.2.3