On Wed, Jun 08, 2022 at 10:35:42AM +0800, Guo Ren wrote: > . > > On Wed, Jun 8, 2022 at 8:02 AM Jarkko Sakkinen <jarkko@xxxxxxxxxxx> wrote: > > > > Tracing with kprobes while running a monolithic kernel is currently > > impossible because CONFIG_KPROBES is dependent of CONFIG_MODULES. This > > dependency is a result of kprobes code using the module allocator for the > > trampoline code. > > > > Detaching kprobes from modules helps to squeeze down the user space, > > e.g. when developing new core kernel features, while still having all > > the nice tracing capabilities. > > > > For kernel/ and arch/*, move module_alloc() and module_memfree() to > > module_alloc.c, and compile as part of vmlinux when either CONFIG_MODULES > > or CONFIG_KPROBES is enabled. In addition, flag kernel module specific > > code with CONFIG_MODULES. > > > > As the result, kprobes can be used with a monolithic kernel. > It's strange when MODULES is n, but vmlinux still obtains module_alloc. > > Maybe we need a kprobe_alloc, right? Perhaps not the best name but at least it documents the fact that they use the same allocator. Few years ago I carved up something "half-way there" for kprobes, and I used the name text_alloc() [*]. [*] https://lore.kernel.org/all/20200724050553.1724168-1-jarkko.sakkinen@xxxxxxxxxxxxxxx/ BR, Jarkko
