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author | Josh Poimboeuf <jpoimboe@redhat.com> | 2015-02-09 11:31:13 -0600 |
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committer | Jiri Kosina <jkosina@suse.cz> | 2015-02-18 21:06:38 +0100 |
commit | 0937e3b025f70e33f018aa55ee8d32b8731730a7 (patch) | |
tree | f8bed0ffeae83f15e02f6f60bd1d910d9791836b | |
parent | 4421f8f0fa02bc982b410cd773223cc280791c54 (diff) | |
download | linux-stable-0937e3b025f70e33f018aa55ee8d32b8731730a7.tar.gz linux-stable-0937e3b025f70e33f018aa55ee8d32b8731730a7.tar.bz2 linux-stable-0937e3b025f70e33f018aa55ee8d32b8731730a7.zip |
livepatch: simplify disable error path
If registering the function with ftrace has previously succeeded,
unregistering will almost never fail. Even if it does, it's not a fatal
error. We can still carry on and disable the klp_func from being used
by removing it from the klp_ops func stack.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
-rw-r--r-- | kernel/livepatch/core.c | 67 |
1 files changed, 17 insertions, 50 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index ff7f47d026ac..26df09d56f7c 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -322,32 +322,20 @@ static void notrace klp_ftrace_handler(unsigned long ip, klp_arch_set_pc(regs, (unsigned long)func->new_func); } -static int klp_disable_func(struct klp_func *func) +static void klp_disable_func(struct klp_func *func) { struct klp_ops *ops; - int ret; - - if (WARN_ON(func->state != KLP_ENABLED)) - return -EINVAL; - if (WARN_ON(!func->old_addr)) - return -EINVAL; + WARN_ON(func->state != KLP_ENABLED); + WARN_ON(!func->old_addr); ops = klp_find_ops(func->old_addr); if (WARN_ON(!ops)) - return -EINVAL; + return; if (list_is_singular(&ops->func_stack)) { - ret = unregister_ftrace_function(&ops->fops); - if (ret) { - pr_err("failed to unregister ftrace handler for function '%s' (%d)\n", - func->old_name, ret); - return ret; - } - - ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0); - if (ret) - pr_warn("function unregister succeeded but failed to clear the filter\n"); + WARN_ON(unregister_ftrace_function(&ops->fops)); + WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0)); list_del_rcu(&func->stack_node); list_del(&ops->node); @@ -357,8 +345,6 @@ static int klp_disable_func(struct klp_func *func) } func->state = KLP_DISABLED; - - return 0; } static int klp_enable_func(struct klp_func *func) @@ -419,23 +405,15 @@ err: return ret; } -static int klp_disable_object(struct klp_object *obj) +static void klp_disable_object(struct klp_object *obj) { struct klp_func *func; - int ret; - for (func = obj->funcs; func->old_name; func++) { - if (func->state != KLP_ENABLED) - continue; - - ret = klp_disable_func(func); - if (ret) - return ret; - } + for (func = obj->funcs; func->old_name; func++) + if (func->state == KLP_ENABLED) + klp_disable_func(func); obj->state = KLP_DISABLED; - - return 0; } static int klp_enable_object(struct klp_object *obj) @@ -451,22 +429,19 @@ static int klp_enable_object(struct klp_object *obj) for (func = obj->funcs; func->old_name; func++) { ret = klp_enable_func(func); - if (ret) - goto unregister; + if (ret) { + klp_disable_object(obj); + return ret; + } } obj->state = KLP_ENABLED; return 0; - -unregister: - WARN_ON(klp_disable_object(obj)); - return ret; } static int __klp_disable_patch(struct klp_patch *patch) { struct klp_object *obj; - int ret; /* enforce stacking: only the last enabled patch can be disabled */ if (!list_is_last(&patch->list, &klp_patches) && @@ -476,12 +451,8 @@ static int __klp_disable_patch(struct klp_patch *patch) pr_notice("disabling patch '%s'\n", patch->mod->name); for (obj = patch->objs; obj->funcs; obj++) { - if (obj->state != KLP_ENABLED) - continue; - - ret = klp_disable_object(obj); - if (ret) - return ret; + if (obj->state == KLP_ENABLED) + klp_disable_object(obj); } patch->state = KLP_DISABLED; @@ -931,7 +902,6 @@ static void klp_module_notify_going(struct klp_patch *patch, { struct module *pmod = patch->mod; struct module *mod = obj->mod; - int ret; if (patch->state == KLP_DISABLED) goto disabled; @@ -939,10 +909,7 @@ static void klp_module_notify_going(struct klp_patch *patch, pr_notice("reverting patch '%s' on unloading module '%s'\n", pmod->name, mod->name); - ret = klp_disable_object(obj); - if (ret) - pr_warn("failed to revert patch '%s' on module '%s' (%d)\n", - pmod->name, mod->name, ret); + klp_disable_object(obj); disabled: klp_free_object_loaded(obj); |