Messages in this thread | | | Date | Thu, 18 Mar 2021 11:13:08 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH 3/3] static_call: Fix static_call_update() sanity check |
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On Thu, Mar 18, 2021 at 12:31:59PM +0100, Peter Zijlstra wrote: > if (!kernel_text_address((unsigned long)site_addr)) { > - WARN_ONCE(1, "can't patch static call site at %pS", > + /* > + * This skips patching __exit, which is part of > + * init_section_contains() but is not part of > + * kernel_text_address(). > + * > + * Skipping __exit is fine since it will never > + * be executed. > + */ > + WARN_ONCE(!static_call_is_init(site), > + "can't patch static call site at %pS", > site_addr); > continue; > }
It might be good to clarify the situation for __exit in modules in the comment and/or changelog, as they both seem to be implicitly talking only about __exit in vmlinux.
For CONFIG_MODULE_UNLOAD, the code ends up in the normal text area, so static_call_is_init() is false and kernel_text_address() is true.
For !CONFIG_MODULE_UNLOAD, the code gets discarded during module load, so static_call_is_init() and kernel_text_address() are both false. I guess that will trigger a warning?
-- Josh
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