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 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 index 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
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20210318113610.636651340@infradead.org \ --to=peterz@infradead.org \ --cc=ardb@kernel.org \ --cc=jarkko@kernel.org \ --cc=jbaron@akamai.com \ --cc=jpoimboe@redhat.com \ --cc=linux-kernel@vger.kernel.org \ --cc=oliver.sang@intel.com \ --cc=rostedt@goodmis.org \ --cc=sumit.garg@linaro.org \ --cc=x86@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
LKML Archive on lore.kernel.org Archives are clonable: git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git # If you have public-inbox 1.1+ installed, you may # initialize and index your mirror using the following commands: public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \ linux-kernel@vger.kernel.org public-inbox-index lkml Example config snippet for mirrors Newsgroup available over NNTP: nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel AGPL code for this site: git clone https://public-inbox.org/public-inbox.git