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author | Masami Hiramatsu <mhiramat@kernel.org> | 2018-01-13 02:55:03 +0900 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2018-01-12 17:33:38 -0800 |
commit | 540adea3809f61115d2a1ea4ed6e627613452ba1 (patch) | |
tree | 03ba07d13807d06d52053b2d02565075f210c2e2 /kernel | |
parent | 66665ad2f1023d3ffb0c12eea9e0a6d0b613ecb3 (diff) | |
download | linux-540adea3809f61115d2a1ea4ed6e627613452ba1.tar.gz linux-540adea3809f61115d2a1ea4ed6e627613452ba1.tar.bz2 linux-540adea3809f61115d2a1ea4ed6e627613452ba1.zip |
error-injection: Separate error-injection from kprobe
Since error-injection framework is not limited to be used
by kprobes, nor bpf. Other kernel subsystems can use it
freely for checking safeness of error-injection, e.g.
livepatch, ftrace etc.
So this separate error-injection framework from kprobes.
Some differences has been made:
- "kprobe" word is removed from any APIs/structures.
- BPF_ALLOW_ERROR_INJECTION() is renamed to
ALLOW_ERROR_INJECTION() since it is not limited for BPF too.
- CONFIG_FUNCTION_ERROR_INJECTION is the config item of this
feature. It is automatically enabled if the arch supports
error injection feature for kprobe or ftrace etc.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/kprobes.c | 163 | ||||
-rw-r--r-- | kernel/module.c | 8 | ||||
-rw-r--r-- | kernel/trace/Kconfig | 2 | ||||
-rw-r--r-- | kernel/trace/bpf_trace.c | 4 | ||||
-rw-r--r-- | kernel/trace/trace_kprobe.c | 3 |
5 files changed, 9 insertions, 171 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index b4aab48ad258..da2ccf142358 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -83,16 +83,6 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash) return &(kretprobe_table_locks[hash].lock); } -/* List of symbols that can be overriden for error injection. */ -static LIST_HEAD(kprobe_error_injection_list); -static DEFINE_MUTEX(kprobe_ei_mutex); -struct kprobe_ei_entry { - struct list_head list; - unsigned long start_addr; - unsigned long end_addr; - void *priv; -}; - /* Blacklist -- list of struct kprobe_blacklist_entry */ static LIST_HEAD(kprobe_blacklist); @@ -1404,17 +1394,6 @@ bool within_kprobe_blacklist(unsigned long addr) return false; } -bool within_kprobe_error_injection_list(unsigned long addr) -{ - struct kprobe_ei_entry *ent; - - list_for_each_entry(ent, &kprobe_error_injection_list, list) { - if (addr >= ent->start_addr && addr < ent->end_addr) - return true; - } - return false; -} - /* * If we have a symbol_name argument, look it up and add the offset field * to it. This way, we can specify a relative address to a symbol. @@ -2189,86 +2168,6 @@ static int __init populate_kprobe_blacklist(unsigned long *start, return 0; } -#ifdef CONFIG_BPF_KPROBE_OVERRIDE -/* Markers of the _kprobe_error_inject_list section */ -extern unsigned long __start_kprobe_error_inject_list[]; -extern unsigned long __stop_kprobe_error_inject_list[]; - -/* - * Lookup and populate the kprobe_error_injection_list. - * - * For safety reasons we only allow certain functions to be overriden with - * bpf_error_injection, so we need to populate the list of the symbols that have - * been marked as safe for overriding. - */ -static void populate_kprobe_error_injection_list(unsigned long *start, - unsigned long *end, - void *priv) -{ - unsigned long *iter; - struct kprobe_ei_entry *ent; - unsigned long entry, offset = 0, size = 0; - - mutex_lock(&kprobe_ei_mutex); - for (iter = start; iter < end; iter++) { - entry = arch_deref_entry_point((void *)*iter); - - if (!kernel_text_address(entry) || - !kallsyms_lookup_size_offset(entry, &size, &offset)) { - pr_err("Failed to find error inject entry at %p\n", - (void *)entry); - continue; - } - - ent = kmalloc(sizeof(*ent), GFP_KERNEL); - if (!ent) - break; - ent->start_addr = entry; - ent->end_addr = entry + size; - ent->priv = priv; - INIT_LIST_HEAD(&ent->list); - list_add_tail(&ent->list, &kprobe_error_injection_list); - } - mutex_unlock(&kprobe_ei_mutex); -} - -static void __init populate_kernel_kprobe_ei_list(void) -{ - populate_kprobe_error_injection_list(__start_kprobe_error_inject_list, - __stop_kprobe_error_inject_list, - NULL); -} - -static void module_load_kprobe_ei_list(struct module *mod) -{ - if (!mod->num_kprobe_ei_funcs) - return; - populate_kprobe_error_injection_list(mod->kprobe_ei_funcs, - mod->kprobe_ei_funcs + - mod->num_kprobe_ei_funcs, mod); -} - -static void module_unload_kprobe_ei_list(struct module *mod) -{ - struct kprobe_ei_entry *ent, *n; - if (!mod->num_kprobe_ei_funcs) - return; - - mutex_lock(&kprobe_ei_mutex); - list_for_each_entry_safe(ent, n, &kprobe_error_injection_list, list) { - if (ent->priv == mod) { - list_del_init(&ent->list); - kfree(ent); - } - } - mutex_unlock(&kprobe_ei_mutex); -} -#else -static inline void __init populate_kernel_kprobe_ei_list(void) {} -static inline void module_load_kprobe_ei_list(struct module *m) {} -static inline void module_unload_kprobe_ei_list(struct module *m) {} -#endif - /* Module notifier call back, checking kprobes on the module */ static int kprobes_module_callback(struct notifier_block *nb, unsigned long val, void *data) @@ -2279,11 +2178,6 @@ static int kprobes_module_callback(struct notifier_block *nb, unsigned int i; int checkcore = (val == MODULE_STATE_GOING); - if (val == MODULE_STATE_COMING) - module_load_kprobe_ei_list(mod); - else if (val == MODULE_STATE_GOING) - module_unload_kprobe_ei_list(mod); - if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE) return NOTIFY_DONE; @@ -2346,8 +2240,6 @@ static int __init init_kprobes(void) pr_err("Please take care of using kprobes.\n"); } - populate_kernel_kprobe_ei_list(); - if (kretprobe_blacklist_size) { /* lookup the function address from its name */ for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { @@ -2515,56 +2407,6 @@ static const struct file_operations debugfs_kprobe_blacklist_ops = { .release = seq_release, }; -/* - * kprobes/error_injection_list -- shows which functions can be overriden for - * error injection. - * */ -static void *kprobe_ei_seq_start(struct seq_file *m, loff_t *pos) -{ - mutex_lock(&kprobe_ei_mutex); - return seq_list_start(&kprobe_error_injection_list, *pos); -} - -static void kprobe_ei_seq_stop(struct seq_file *m, void *v) -{ - mutex_unlock(&kprobe_ei_mutex); -} - -static void *kprobe_ei_seq_next(struct seq_file *m, void *v, loff_t *pos) -{ - return seq_list_next(v, &kprobe_error_injection_list, pos); -} - -static int kprobe_ei_seq_show(struct seq_file *m, void *v) -{ - char buffer[KSYM_SYMBOL_LEN]; - struct kprobe_ei_entry *ent = - list_entry(v, struct kprobe_ei_entry, list); - - sprint_symbol(buffer, ent->start_addr); - seq_printf(m, "%s\n", buffer); - return 0; -} - -static const struct seq_operations kprobe_ei_seq_ops = { - .start = kprobe_ei_seq_start, - .next = kprobe_ei_seq_next, - .stop = kprobe_ei_seq_stop, - .show = kprobe_ei_seq_show, -}; - -static int kprobe_ei_open(struct inode *inode, struct file *filp) -{ - return seq_open(filp, &kprobe_ei_seq_ops); -} - -static const struct file_operations debugfs_kprobe_ei_ops = { - .open = kprobe_ei_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, -}; - static void arm_all_kprobes(void) { struct hlist_head *head; @@ -2706,11 +2548,6 @@ static int __init debugfs_kprobe_init(void) if (!file) goto error; - file = debugfs_create_file("error_injection_list", 0444, dir, NULL, - &debugfs_kprobe_ei_ops); - if (!file) - goto error; - return 0; error: diff --git a/kernel/module.c b/kernel/module.c index bd695bfdc5c4..601494d4b7ea 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3118,10 +3118,10 @@ static int find_module_sections(struct module *mod, struct load_info *info) sizeof(*mod->ftrace_callsites), &mod->num_ftrace_callsites); #endif -#ifdef CONFIG_BPF_KPROBE_OVERRIDE - mod->kprobe_ei_funcs = section_objs(info, "_kprobe_error_inject_list", - sizeof(*mod->kprobe_ei_funcs), - &mod->num_kprobe_ei_funcs); +#ifdef CONFIG_FUNCTION_ERROR_INJECTION + mod->ei_funcs = section_objs(info, "_error_injection_whitelist", + sizeof(*mod->ei_funcs), + &mod->num_ei_funcs); #endif mod->extable = section_objs(info, "__ex_table", sizeof(*mod->extable), &mod->num_exentries); diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 6400e1bf97c5..7114c885a78a 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -533,7 +533,7 @@ config FUNCTION_PROFILER config BPF_KPROBE_OVERRIDE bool "Enable BPF programs to override a kprobed function" depends on BPF_EVENTS - depends on HAVE_KPROBE_OVERRIDE + depends on FUNCTION_ERROR_INJECTION default n help Allows BPF to override the execution of a probed function and diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 24ed6363e00f..f274468cbc45 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -14,7 +14,7 @@ #include <linux/uaccess.h> #include <linux/ctype.h> #include <linux/kprobes.h> -#include <asm/kprobes.h> +#include <linux/error-injection.h> #include "trace_probe.h" #include "trace.h" @@ -84,7 +84,7 @@ EXPORT_SYMBOL_GPL(trace_call_bpf); BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc) { regs_set_return_value(regs, rc); - arch_kprobe_override_function(regs); + override_function_with_return(regs); return 0; } diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index b8c90441bc87..1fad24acd444 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -21,6 +21,7 @@ #include <linux/module.h> #include <linux/uaccess.h> #include <linux/rculist.h> +#include <linux/error-injection.h> #include "trace_probe.h" @@ -107,7 +108,7 @@ bool trace_kprobe_error_injectable(struct trace_event_call *call) } else { addr = (unsigned long)tk->rp.kp.addr; } - return within_kprobe_error_injection_list(addr); + return within_error_injection_list(addr); } static int register_kprobe_event(struct trace_kprobe *tk); |