From 70283454c918f1d65de0ec50c45ef592d781bcae Mon Sep 17 00:00:00 2001 From: Kimberly Brown Date: Mon, 1 Apr 2019 22:51:58 -0400 Subject: livepatch: Replace klp_ktype_patch's default_attrs with groups The kobj_type default_attrs field is being replaced by the default_groups field. Replace klp_ktype_patch's default_attrs field with default_groups and use the ATTRIBUTE_GROUPS macro to create klp_patch_groups. This patch was tested by loading the livepatch-sample module and verifying that the sysfs files for the attributes in the default groups were created. Signed-off-by: Kimberly Brown Acked-by: Jiri Kosina Acked-by: Miroslav Benes Acked-by: Petr Mladek Signed-off-by: Greg Kroah-Hartman --- kernel/livepatch/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index eb0ee10a1981..34a8338657d2 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -419,6 +419,7 @@ static struct attribute *klp_patch_attrs[] = { &force_kobj_attr.attr, NULL }; +ATTRIBUTE_GROUPS(klp_patch); static void klp_free_object_dynamic(struct klp_object *obj) { @@ -546,7 +547,7 @@ static void klp_kobj_release_patch(struct kobject *kobj) static struct kobj_type klp_ktype_patch = { .release = klp_kobj_release_patch, .sysfs_ops = &kobj_sysfs_ops, - .default_attrs = klp_patch_attrs, + .default_groups = klp_patch_groups, }; static void klp_kobj_release_object(struct kobject *kobj) -- cgit v1.2.3 From 25e39e32b0a3f99b9db320605f20f91d425b6a65 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 25 Apr 2019 11:45:18 +0200 Subject: livepatch: Simplify stack trace retrieval Replace the indirection through struct stack_trace by using the storage array based interfaces. Signed-off-by: Thomas Gleixner Reviewed-by: Josh Poimboeuf Acked-by: Miroslav Benes Cc: Andy Lutomirski Cc: Steven Rostedt Cc: Alexander Potapenko Cc: Alexey Dobriyan Cc: Andrew Morton Cc: Christoph Lameter Cc: Pekka Enberg Cc: linux-mm@kvack.org Cc: David Rientjes Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport Cc: Akinobu Mita Cc: Christoph Hellwig Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy Cc: Marek Szyprowski Cc: Johannes Thumshirn Cc: David Sterba Cc: Chris Mason Cc: Josef Bacik Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer Cc: Alasdair Kergon Cc: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen Cc: Maarten Lankhorst Cc: dri-devel@lists.freedesktop.org Cc: David Airlie Cc: Jani Nikula Cc: Rodrigo Vivi Cc: Tom Zanussi Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094803.437950229@linutronix.de --- kernel/livepatch/transition.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index 9c89ae8b337a..c53370d596be 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -202,15 +202,15 @@ void klp_update_patch_state(struct task_struct *task) * Determine whether the given stack trace includes any references to a * to-be-patched or to-be-unpatched function. */ -static int klp_check_stack_func(struct klp_func *func, - struct stack_trace *trace) +static int klp_check_stack_func(struct klp_func *func, unsigned long *entries, + unsigned int nr_entries) { unsigned long func_addr, func_size, address; struct klp_ops *ops; int i; - for (i = 0; i < trace->nr_entries; i++) { - address = trace->entries[i]; + for (i = 0; i < nr_entries; i++) { + address = entries[i]; if (klp_target_state == KLP_UNPATCHED) { /* @@ -254,29 +254,25 @@ static int klp_check_stack_func(struct klp_func *func, static int klp_check_stack(struct task_struct *task, char *err_buf) { static unsigned long entries[MAX_STACK_ENTRIES]; - struct stack_trace trace; struct klp_object *obj; struct klp_func *func; - int ret; + int ret, nr_entries; - trace.skip = 0; - trace.nr_entries = 0; - trace.max_entries = MAX_STACK_ENTRIES; - trace.entries = entries; - ret = save_stack_trace_tsk_reliable(task, &trace); + ret = stack_trace_save_tsk_reliable(task, entries, ARRAY_SIZE(entries)); WARN_ON_ONCE(ret == -ENOSYS); - if (ret) { + if (ret < 0) { snprintf(err_buf, STACK_ERR_BUF_SIZE, "%s: %s:%d has an unreliable stack\n", __func__, task->comm, task->pid); return ret; } + nr_entries = ret; klp_for_each_object(klp_transition_patch, obj) { if (!obj->patched) continue; klp_for_each_func(obj, func) { - ret = klp_check_stack_func(func, &trace); + ret = klp_check_stack_func(func, entries, nr_entries); if (ret) { snprintf(err_buf, STACK_ERR_BUF_SIZE, "%s: %s:%d is sleeping on function %s\n", -- cgit v1.2.3 From 31adf2308f33dcae59009019675224be0978bc70 Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Wed, 24 Apr 2019 10:55:48 +0200 Subject: livepatch: Convert error about unsupported reliable stacktrace into a warning The commit d0807da78e11d46f ("livepatch: Remove immediate feature") caused that any livepatch was refused when reliable stacktraces were not supported on the given architecture. The limitation is too strong. User space processes are safely migrated even when entering or leaving the kernel. Kthreads transition would need to get forced. But it is safe when: + The livepatch does not change the semantic of the code. + Callbacks do not depend on a safely finished transition. Suggested-by: Josh Poimboeuf Acked-by: Josh Poimboeuf Acked-by: Miroslav Benes Reviewed-by: Kamalesh Babulal Signed-off-by: Petr Mladek --- kernel/livepatch/core.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index eb0ee10a1981..14f33ab6c583 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -1003,11 +1003,10 @@ int klp_enable_patch(struct klp_patch *patch) return -ENODEV; if (!klp_have_reliable_stack()) { - pr_err("This architecture doesn't have support for the livepatch consistency model.\n"); - return -EOPNOTSUPP; + pr_warn("This architecture doesn't have support for the livepatch consistency model.\n"); + pr_warn("The livepatch transition may never complete.\n"); } - mutex_lock(&klp_mutex); ret = klp_init_patch_early(patch); -- cgit v1.2.3 From 4d141ab3416d90f87775f5dee725efdf40110a8f Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Fri, 3 May 2019 15:26:24 +0200 Subject: livepatch: Remove custom kobject state handling kobject_init() always succeeds and sets the reference count to 1. It allows to always free the structures via kobject_put() and the related release callback. Note that the custom kobject state handling was used only because we did not know that kobject_put() can and actually should get called even when kobject_init_and_add() fails. The patch should not change the existing behavior. Suggested-by: "Tobin C. Harding" Signed-off-by: Petr Mladek Reviewed-by: Kamalesh Babulal Acked-by: Joe Lawrence Signed-off-by: Jiri Kosina --- kernel/livepatch/core.c | 56 +++++++++++++++---------------------------------- 1 file changed, 17 insertions(+), 39 deletions(-) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 14f33ab6c583..42385f23252a 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -426,6 +426,9 @@ static void klp_free_object_dynamic(struct klp_object *obj) kfree(obj); } +static struct kobj_type klp_ktype_object; +static struct kobj_type klp_ktype_func; + static struct klp_object *klp_alloc_object_dynamic(const char *name) { struct klp_object *obj; @@ -443,6 +446,7 @@ static struct klp_object *klp_alloc_object_dynamic(const char *name) } INIT_LIST_HEAD(&obj->func_list); + kobject_init(&obj->kobj, &klp_ktype_object); obj->dynamic = true; return obj; @@ -471,6 +475,7 @@ static struct klp_func *klp_alloc_func_nop(struct klp_func *old_func, } } + kobject_init(&func->kobj, &klp_ktype_func); /* * func->new_func is same as func->old_func. These addresses are * set when the object is loaded, see klp_init_object_loaded(). @@ -588,13 +593,7 @@ static void __klp_free_funcs(struct klp_object *obj, bool nops_only) continue; list_del(&func->node); - - /* Might be called from klp_init_patch() error path. */ - if (func->kobj_added) { - kobject_put(&func->kobj); - } else if (func->nop) { - klp_free_func_nop(func); - } + kobject_put(&func->kobj); } } @@ -624,13 +623,7 @@ static void __klp_free_objects(struct klp_patch *patch, bool nops_only) continue; list_del(&obj->node); - - /* Might be called from klp_init_patch() error path. */ - if (obj->kobj_added) { - kobject_put(&obj->kobj); - } else if (obj->dynamic) { - klp_free_object_dynamic(obj); - } + kobject_put(&obj->kobj); } } @@ -675,10 +668,8 @@ static void klp_free_patch_finish(struct klp_patch *patch) * this is called when the patch gets disabled and it * cannot get enabled again. */ - if (patch->kobj_added) { - kobject_put(&patch->kobj); - wait_for_completion(&patch->finish); - } + kobject_put(&patch->kobj); + wait_for_completion(&patch->finish); /* Put the module after the last access to struct klp_patch. */ if (!patch->forced) @@ -700,8 +691,6 @@ static void klp_free_patch_work_fn(struct work_struct *work) static int klp_init_func(struct klp_object *obj, struct klp_func *func) { - int ret; - if (!func->old_name) return -EINVAL; @@ -724,13 +713,9 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func) * object. If the user selects 0 for old_sympos, then 1 will be used * since a unique symbol will be the first occurrence. */ - ret = kobject_init_and_add(&func->kobj, &klp_ktype_func, - &obj->kobj, "%s,%lu", func->old_name, - func->old_sympos ? func->old_sympos : 1); - if (!ret) - func->kobj_added = true; - - return ret; + return kobject_add(&func->kobj, &obj->kobj, "%s,%lu", + func->old_name, + func->old_sympos ? func->old_sympos : 1); } /* Arches may override this to finish any remaining arch-specific tasks */ @@ -801,11 +786,9 @@ static int klp_init_object(struct klp_patch *patch, struct klp_object *obj) klp_find_object_module(obj); name = klp_is_module(obj) ? obj->name : "vmlinux"; - ret = kobject_init_and_add(&obj->kobj, &klp_ktype_object, - &patch->kobj, "%s", name); + ret = kobject_add(&obj->kobj, &patch->kobj, "%s", name); if (ret) return ret; - obj->kobj_added = true; klp_for_each_func(obj, func) { ret = klp_init_func(obj, func); @@ -829,7 +812,7 @@ static int klp_init_patch_early(struct klp_patch *patch) INIT_LIST_HEAD(&patch->list); INIT_LIST_HEAD(&patch->obj_list); - patch->kobj_added = false; + kobject_init(&patch->kobj, &klp_ktype_patch); patch->enabled = false; patch->forced = false; INIT_WORK(&patch->free_work, klp_free_patch_work_fn); @@ -840,11 +823,11 @@ static int klp_init_patch_early(struct klp_patch *patch) return -EINVAL; INIT_LIST_HEAD(&obj->func_list); - obj->kobj_added = false; + kobject_init(&obj->kobj, &klp_ktype_object); list_add_tail(&obj->node, &patch->obj_list); klp_for_each_func_static(obj, func) { - func->kobj_added = false; + kobject_init(&func->kobj, &klp_ktype_func); list_add_tail(&func->node, &obj->func_list); } } @@ -860,11 +843,9 @@ static int klp_init_patch(struct klp_patch *patch) struct klp_object *obj; int ret; - ret = kobject_init_and_add(&patch->kobj, &klp_ktype_patch, - klp_root_kobj, "%s", patch->mod->name); + ret = kobject_add(&patch->kobj, klp_root_kobj, "%s", patch->mod->name); if (ret) return ret; - patch->kobj_added = true; if (patch->replace) { ret = klp_add_nops(patch); @@ -926,9 +907,6 @@ static int __klp_enable_patch(struct klp_patch *patch) if (WARN_ON(patch->enabled)) return -EINVAL; - if (!patch->kobj_added) - return -EINVAL; - pr_notice("enabling patch '%s'\n", patch->mod->name); klp_init_transition(patch, KLP_PATCHED); -- cgit v1.2.3 From f68d67cf2f83dc82675969724b59ca7c6da43fa9 Mon Sep 17 00:00:00 2001 From: Petr Mladek Date: Fri, 3 May 2019 15:26:25 +0200 Subject: livepatch: Remove duplicated code for early initialization kobject_init() call added one more operation that has to be done when doing the early initialization of both static and dynamic livepatch structures. It would have been easier when the early initialization code was not duplicated. Let's deduplicate it for future generations of livepatching hackers. The patch does not change the existing behavior. Signed-off-by: Petr Mladek Reviewed-by: Kamalesh Babulal Acked-by: Joe Lawrence Signed-off-by: Jiri Kosina --- kernel/livepatch/core.c | 42 ++++++++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 16 deletions(-) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 42385f23252a..f12c0eabd843 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -426,10 +426,13 @@ static void klp_free_object_dynamic(struct klp_object *obj) kfree(obj); } -static struct kobj_type klp_ktype_object; -static struct kobj_type klp_ktype_func; +static void klp_init_func_early(struct klp_object *obj, + struct klp_func *func); +static void klp_init_object_early(struct klp_patch *patch, + struct klp_object *obj); -static struct klp_object *klp_alloc_object_dynamic(const char *name) +static struct klp_object *klp_alloc_object_dynamic(const char *name, + struct klp_patch *patch) { struct klp_object *obj; @@ -445,8 +448,7 @@ static struct klp_object *klp_alloc_object_dynamic(const char *name) } } - INIT_LIST_HEAD(&obj->func_list); - kobject_init(&obj->kobj, &klp_ktype_object); + klp_init_object_early(patch, obj); obj->dynamic = true; return obj; @@ -475,7 +477,7 @@ static struct klp_func *klp_alloc_func_nop(struct klp_func *old_func, } } - kobject_init(&func->kobj, &klp_ktype_func); + klp_init_func_early(obj, func); /* * func->new_func is same as func->old_func. These addresses are * set when the object is loaded, see klp_init_object_loaded(). @@ -495,11 +497,9 @@ static int klp_add_object_nops(struct klp_patch *patch, obj = klp_find_object(patch, old_obj); if (!obj) { - obj = klp_alloc_object_dynamic(old_obj->name); + obj = klp_alloc_object_dynamic(old_obj->name, patch); if (!obj) return -ENOMEM; - - list_add_tail(&obj->node, &patch->obj_list); } klp_for_each_func(old_obj, old_func) { @@ -510,8 +510,6 @@ static int klp_add_object_nops(struct klp_patch *patch, func = klp_alloc_func_nop(old_func, obj); if (!func) return -ENOMEM; - - list_add_tail(&func->node, &obj->func_list); } return 0; @@ -802,6 +800,21 @@ static int klp_init_object(struct klp_patch *patch, struct klp_object *obj) return ret; } +static void klp_init_func_early(struct klp_object *obj, + struct klp_func *func) +{ + kobject_init(&func->kobj, &klp_ktype_func); + list_add_tail(&func->node, &obj->func_list); +} + +static void klp_init_object_early(struct klp_patch *patch, + struct klp_object *obj) +{ + INIT_LIST_HEAD(&obj->func_list); + kobject_init(&obj->kobj, &klp_ktype_object); + list_add_tail(&obj->node, &patch->obj_list); +} + static int klp_init_patch_early(struct klp_patch *patch) { struct klp_object *obj; @@ -822,13 +835,10 @@ static int klp_init_patch_early(struct klp_patch *patch) if (!obj->funcs) return -EINVAL; - INIT_LIST_HEAD(&obj->func_list); - kobject_init(&obj->kobj, &klp_ktype_object); - list_add_tail(&obj->node, &patch->obj_list); + klp_init_object_early(patch, obj); klp_for_each_func_static(obj, func) { - kobject_init(&func->kobj, &klp_ktype_func); - list_add_tail(&func->node, &obj->func_list); + klp_init_func_early(obj, func); } } -- cgit v1.2.3 From 56e33afd7757d5da2664fb797f2544ce167176be Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Fri, 10 May 2019 23:47:50 +0200 Subject: livepatch: Remove klp_check_compiler_support() The only purpose of klp_check_compiler_support() is to make sure that we are not using ftrace on x86 via mcount (because that's executed only after prologue has already happened, and that's too late for livepatching purposes). Now that mcount is not supported by ftrace any more, there is no need for klp_check_compiler_support() either. Link: http://lkml.kernel.org/r/nycvar.YFH.7.76.1905102346100.17054@cbobk.fhfr.pm Reported-by: Linus Torvalds Signed-off-by: Jiri Kosina Signed-off-by: Steven Rostedt (VMware) --- kernel/livepatch/core.c | 8 -------- 1 file changed, 8 deletions(-) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index eb0ee10a1981..112a36ed4a09 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -1220,14 +1220,6 @@ void klp_module_going(struct module *mod) static int __init klp_init(void) { - int ret; - - ret = klp_check_compiler_support(); - if (ret) { - pr_info("Your compiler is too old; turning off.\n"); - return -EINVAL; - } - klp_root_kobj = kobject_create_and_add("livepatch", kernel_kobj); if (!klp_root_kobj) return -ENOMEM; -- cgit v1.2.3 From ec8f24b7faaf3d4799a7c3f4c1b87f6b02778ad1 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 19 May 2019 13:07:45 +0100 Subject: treewide: Add SPDX license identifier - Makefile/Kconfig Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- kernel/livepatch/Kconfig | 1 + kernel/livepatch/Makefile | 1 + 2 files changed, 2 insertions(+) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/Kconfig b/kernel/livepatch/Kconfig index ec4565122e65..54102deb50ba 100644 --- a/kernel/livepatch/Kconfig +++ b/kernel/livepatch/Kconfig @@ -1,3 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0-only config HAVE_LIVEPATCH bool help diff --git a/kernel/livepatch/Makefile b/kernel/livepatch/Makefile index b36ceda6488e..cf9b5bcdb952 100644 --- a/kernel/livepatch/Makefile +++ b/kernel/livepatch/Makefile @@ -1,3 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0-only obj-$(CONFIG_LIVEPATCH) += livepatch.o livepatch-objs := core.o patch.o shadow.o transition.o -- cgit v1.2.3 From 1ccea77e2a2687cae171b7987eb44730ec8c6d5f Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 19 May 2019 15:51:43 +0200 Subject: treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details [based] [from] [clk] [highbank] [c] you should have received a copy of the gnu general public license along with this program if not see http www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 355 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Kate Stewart Reviewed-by: Jilayne Lovejoy Reviewed-by: Steve Winslow Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190519154041.837383322@linutronix.de Signed-off-by: Greg Kroah-Hartman --- kernel/livepatch/core.c | 14 +------------- kernel/livepatch/patch.c | 14 +------------- kernel/livepatch/shadow.c | 14 +------------- kernel/livepatch/transition.c | 14 +------------- 4 files changed, 4 insertions(+), 52 deletions(-) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 91cd519756d3..2398832947c6 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -1,21 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * core.c - Kernel Live Patching Core * * Copyright (C) 2014 Seth Jennings * Copyright (C) 2014 SUSE - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version 2 - * of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, see . */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c index 99cb3ad05eb4..bd43537702bd 100644 --- a/kernel/livepatch/patch.c +++ b/kernel/livepatch/patch.c @@ -1,22 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * patch.c - livepatch patching functions * * Copyright (C) 2014 Seth Jennings * Copyright (C) 2014 SUSE * Copyright (C) 2015 Josh Poimboeuf - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version 2 - * of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, see . */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt diff --git a/kernel/livepatch/shadow.c b/kernel/livepatch/shadow.c index 83958c814439..e5c9fb295ba9 100644 --- a/kernel/livepatch/shadow.c +++ b/kernel/livepatch/shadow.c @@ -1,22 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * shadow.c - Shadow Variables * * Copyright (C) 2014 Josh Poimboeuf * Copyright (C) 2014 Seth Jennings * Copyright (C) 2017 Joe Lawrence - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version 2 - * of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, see . */ /** diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c index c53370d596be..abb2a4a2cbb2 100644 --- a/kernel/livepatch/transition.c +++ b/kernel/livepatch/transition.c @@ -1,20 +1,8 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * transition.c - Kernel Live Patching transition functions * * Copyright (C) 2015-2016 Josh Poimboeuf - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version 2 - * of the License, or (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, see . */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -- cgit v1.2.3 From 9f255b632bf12c4dd7fc31caee89aa991ef75176 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 13 Jun 2019 20:07:22 -0500 Subject: module: Fix livepatch/ftrace module text permissions race It's possible for livepatch and ftrace to be toggling a module's text permissions at the same time, resulting in the following panic: BUG: unable to handle page fault for address: ffffffffc005b1d9 #PF: supervisor write access in kernel mode #PF: error_code(0x0003) - permissions violation PGD 3ea0c067 P4D 3ea0c067 PUD 3ea0e067 PMD 3cc13067 PTE 3b8a1061 Oops: 0003 [#1] PREEMPT SMP PTI CPU: 1 PID: 453 Comm: insmod Tainted: G O K 5.2.0-rc1-a188339ca5 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014 RIP: 0010:apply_relocate_add+0xbe/0x14c Code: fa 0b 74 21 48 83 fa 18 74 38 48 83 fa 0a 75 40 eb 08 48 83 38 00 74 33 eb 53 83 38 00 75 4e 89 08 89 c8 eb 0a 83 38 00 75 43 <89> 08 48 63 c1 48 39 c8 74 2e eb 48 83 38 00 75 32 48 29 c1 89 08 RSP: 0018:ffffb223c00dbb10 EFLAGS: 00010246 RAX: ffffffffc005b1d9 RBX: 0000000000000000 RCX: ffffffff8b200060 RDX: 000000000000000b RSI: 0000004b0000000b RDI: ffff96bdfcd33000 RBP: ffffb223c00dbb38 R08: ffffffffc005d040 R09: ffffffffc005c1f0 R10: ffff96bdfcd33c40 R11: ffff96bdfcd33b80 R12: 0000000000000018 R13: ffffffffc005c1f0 R14: ffffffffc005e708 R15: ffffffff8b2fbc74 FS: 00007f5f447beba8(0000) GS:ffff96bdff900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffc005b1d9 CR3: 000000003cedc002 CR4: 0000000000360ea0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: klp_init_object_loaded+0x10f/0x219 ? preempt_latency_start+0x21/0x57 klp_enable_patch+0x662/0x809 ? virt_to_head_page+0x3a/0x3c ? kfree+0x8c/0x126 patch_init+0x2ed/0x1000 [livepatch_test02] ? 0xffffffffc0060000 do_one_initcall+0x9f/0x1c5 ? kmem_cache_alloc_trace+0xc4/0xd4 ? do_init_module+0x27/0x210 do_init_module+0x5f/0x210 load_module+0x1c41/0x2290 ? fsnotify_path+0x3b/0x42 ? strstarts+0x2b/0x2b ? kernel_read+0x58/0x65 __do_sys_finit_module+0x9f/0xc3 ? __do_sys_finit_module+0x9f/0xc3 __x64_sys_finit_module+0x1a/0x1c do_syscall_64+0x52/0x61 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The above panic occurs when loading two modules at the same time with ftrace enabled, where at least one of the modules is a livepatch module: CPU0 CPU1 klp_enable_patch() klp_init_object_loaded() module_disable_ro() ftrace_module_enable() ftrace_arch_code_modify_post_process() set_all_modules_text_ro() klp_write_object_relocations() apply_relocate_add() *patches read-only code* - BOOM A similar race exists when toggling ftrace while loading a livepatch module. Fix it by ensuring that the livepatch and ftrace code patching operations -- and their respective permissions changes -- are protected by the text_mutex. Link: http://lkml.kernel.org/r/ab43d56ab909469ac5d2520c5d944ad6d4abd476.1560474114.git.jpoimboe@redhat.com Reported-by: Johannes Erdfelt Fixes: 444d13ff10fb ("modules: add ro_after_init support") Acked-by: Jessica Yu Reviewed-by: Petr Mladek Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Steven Rostedt (VMware) --- kernel/livepatch/core.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/livepatch') diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 91cd519756d3..2d17e6e364b5 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include "core.h" #include "patch.h" @@ -730,16 +731,21 @@ static int klp_init_object_loaded(struct klp_patch *patch, struct klp_func *func; int ret; + mutex_lock(&text_mutex); + module_disable_ro(patch->mod); ret = klp_write_object_relocations(patch->mod, obj); if (ret) { module_enable_ro(patch->mod, true); + mutex_unlock(&text_mutex); return ret; } arch_klp_init_object_loaded(patch, obj); module_enable_ro(patch->mod, true); + mutex_unlock(&text_mutex); + klp_for_each_func(obj, func) { ret = klp_find_object_symbol(obj->name, func->old_name, func->old_sympos, -- cgit v1.2.3