From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org, jpoimboe@redhat.com, jbaron@akamai.com,
rostedt@goodmis.org, ardb@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
sumit.garg@linaro.org, oliver.sang@intel.com, jarkko@kernel.org
Subject: [PATCH 2/3] static_call: Align static_call_is_init() patching condition
Date: Thu, 18 Mar 2021 12:31:58 +0100 [thread overview]
Message-ID: <20210318113610.636651340@infradead.org> (raw)
In-Reply-To: 20210318113156.407406787@infradead.org
The intent is to avoid writing init code after init (because the text
might have been freed). The code is needlessly different between
jump_label and static_call and not obviously correct.
The existing code relies on the fact that the module loader clears the
init layout, such that within_module_init() always fails, while
jump_label relies on the module state which is more obvious and
matches the kernel logic.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/static_call.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)
--- a/kernel/static_call.c
+++ b/kernel/static_call.c
@@ -149,6 +149,7 @@ void __static_call_update(struct static_
};
for (site_mod = &first; site_mod; site_mod = site_mod->next) {
+ bool init = system_state < SYSTEM_RUNNING;
struct module *mod = site_mod->mod;
if (!site_mod->sites) {
@@ -168,6 +169,7 @@ void __static_call_update(struct static_
if (mod) {
stop = mod->static_call_sites +
mod->num_static_call_sites;
+ init = mod->state == MODULE_STATE_COMING;
}
#endif
@@ -175,16 +177,8 @@ void __static_call_update(struct static_
site < stop && static_call_key(site) == key; site++) {
void *site_addr = static_call_addr(site);
- if (static_call_is_init(site)) {
- /*
- * Don't write to call sites which were in
- * initmem and have since been freed.
- */
- if (!mod && system_state >= SYSTEM_RUNNING)
- continue;
- if (mod && !within_module_init((unsigned long)site_addr, mod))
- continue;
- }
+ if (!init && static_call_is_init(site))
+ continue;
if (!kernel_text_address((unsigned long)site_addr)) {
WARN_ONCE(1, "can't patch static call site at %pS",
next prev parent reply other threads:[~2021-03-18 11:39 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 11:31 [PATCH 0/3] static_call() vs __exit fixes Peter Zijlstra
2021-03-18 11:31 ` [PATCH 1/3] static_call: Fix static_call_set_init() Peter Zijlstra
2021-03-19 12:25 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-03-18 11:31 ` Peter Zijlstra [this message]
2021-03-19 12:25 ` [tip: locking/urgent] static_call: Align static_call_is_init() patching condition tip-bot2 for Peter Zijlstra
2021-03-19 13:31 ` [PATCH 2/3] " Rasmus Villemoes
2021-03-19 14:13 ` Peter Zijlstra
2021-03-19 14:40 ` Rasmus Villemoes
2021-03-19 15:44 ` Rasmus Villemoes
2021-03-22 16:59 ` Peter Zijlstra
2021-03-18 11:31 ` [PATCH 3/3] static_call: Fix static_call_update() sanity check Peter Zijlstra
2021-03-18 11:42 ` Peter Zijlstra
2021-03-18 16:13 ` Josh Poimboeuf
2021-03-18 16:58 ` Peter Zijlstra
2021-03-19 12:57 ` Peter Zijlstra
2021-03-19 18:00 ` Steven Rostedt
2021-03-19 19:34 ` Peter Zijlstra
2021-03-19 20:57 ` Steven Rostedt
2021-03-22 14:50 ` Jessica Yu
2021-03-22 16:54 ` Peter Zijlstra
2021-03-22 17:36 ` Jessica Yu
2021-03-22 13:07 ` Jessica Yu
2021-03-22 14:06 ` Peter Zijlstra
2021-03-19 12:25 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-03-18 12:15 ` [PATCH 0/3] static_call() vs __exit fixes Sumit Garg
2021-03-18 19:38 ` Jarkko Sakkinen
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