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static_call: Avoid kprobes on inline static_call()s

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Similar to how we disallow kprobes on any other dynamic text
(ftrace/jump_label) also disallow kprobes on inline static_call()s.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200818135804.744920586@infradead.org
This commit is contained in:
Peter Zijlstra
2020-08-18 15:57:43 +02:00
committed by Ingo Molnar
parent 9183c3f9ed
commit 6333e8f73b
4 changed files with 84 additions and 1 deletions
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68
kernel/static_call.c
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@@ -204,8 +204,58 @@ static int __static_call_init(struct module *mod,
return 0;
}
static int addr_conflict(struct static_call_site *site, void *start, void *end)
{
unsigned long addr = (unsigned long)static_call_addr(site);
if (addr <= (unsigned long)end &&
addr + CALL_INSN_SIZE > (unsigned long)start)
return 1;
return 0;
}
static int __static_call_text_reserved(struct static_call_site *iter_start,
struct static_call_site *iter_stop,
void *start, void *end)
{
struct static_call_site *iter = iter_start;
while (iter < iter_stop) {
if (addr_conflict(iter, start, end))
return 1;
iter++;
}
return 0;
}
#ifdef CONFIG_MODULES
static int __static_call_mod_text_reserved(void *start, void *end)
{
struct module *mod;
int ret;
preempt_disable();
mod = __module_text_address((unsigned long)start);
WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
if (!try_module_get(mod))
mod = NULL;
preempt_enable();
if (!mod)
return 0;
ret = __static_call_text_reserved(mod->static_call_sites,
mod->static_call_sites + mod->num_static_call_sites,
start, end);
module_put(mod);
return ret;
}
static int static_call_add_module(struct module *mod)
{
return __static_call_init(mod, mod->static_call_sites,
@@ -273,8 +323,26 @@ static struct notifier_block static_call_module_nb = {
.notifier_call = static_call_module_notify,
};
#else
static inline int __static_call_mod_text_reserved(void *start, void *end)
{
return 0;
}
#endif /* CONFIG_MODULES */
int static_call_text_reserved(void *start, void *end)
{
int ret = __static_call_text_reserved(__start_static_call_sites,
__stop_static_call_sites, start, end);
if (ret)
return ret;
return __static_call_mod_text_reserved(start, end);
}
static void __init static_call_init(void)
{
int ret;