Date: Sat, 15 Feb 2020 21:01:01 +0100 From: =?UTF-8?Q?Stefan_E=c3=9fer?= <se@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Mateusz Guzik <mjguzik@gmail.com>, freebsd-current@freebsd.org Subject: Re: option KDTRACE_HOOKS non-optional after r357912? Message-ID: <185a5721-e891-2c4d-7fc3-b3fbb75f49d7@freebsd.org> In-Reply-To: <20200215174543.GU4808@kib.kiev.ua> References: <ee9f3c6b-a0f9-5586-1713-78d132c1c6d4.ref@yahoo.de> <ee9f3c6b-a0f9-5586-1713-78d132c1c6d4@yahoo.de> <CAGudoHG7F65Pr%2BV=w3BqrT4BKGvujPYB78Vek%2BMRf9je-FWW6g@mail.gmail.com> <57662d12-5c9f-c947-70ca-d1032b82fb3b@freebsd.org> <bf3ca636-e210-d623-251d-ec1e460de7bb@freebsd.org> <20200215174543.GU4808@kib.kiev.ua>
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Am 15.02.20 um 18:45 schrieb Konstantin Belousov: > On Sat, Feb 15, 2020 at 03:58:06PM +0100, Stefan Eßer wrote: >> Am 15.02.20 um 15:40 schrieb Stefan Eßer: >>> Am 15.02.20 um 14:47 schrieb Mateusz Guzik: >>>> On 2/15/20, Stefan Eßer <st.esser@yahoo.de> wrote: >>>>> Hi Mateusz, >>>>> >>>>> your optimization of systrace checks has made KDTRACE_HOOKS mandatory, >>>>> since there are unprotected assignments to systrace_enabled (which is >>>>> defined as constant 0 in kernels without KDTRACE_HOOKS due to your >>>>> change): >>>>> >>>>> /sys/cddl/dev/systrace/systrace.c:322:20: error: expression is not >>>>> assignable >>>>> systrace_enabled = true; >>>>> ~~~~~~~~~~~~~~~~ ^ >>>>> /sys/cddl/dev/systrace/systrace.c:334:20: error: expression is not >>>>> assignable >>>>> systrace_enabled = false; >>>>> ~~~~~~~~~~~~~~~~ ^ >>>>> 2 errors generated. >>>>> *** [systrace.o] Error code 1 >>>>> >>>>> The easy work-around is of course to add KDTRACE_HOOKS to the stripped >>>>> down kernel configuration. But I think there should be stab functions >>>>> in systrace.c to cover the case that this option is not active. >>>>> >>>>> Or is the overhead and other impact of KDTRACE_HOOKS considered to be >>>>> so insignificant that it should be included in every kernel? >>>> >>>> Well tinderbox built for me. >>> >>> Yes, no surprise, KDTRACE_HOOKS is defined in all the GENERIC kernels. >>> >>>> Note that the module strongly depends on KDTRACE_HOOKS to work in the >>>> first place -- even prior to my patch support in the syscall path was gated by >>>> this define. In other words, the module should not be being built if the option >>>> is not enabled. Thus if anything the change adds an unintended improvement >>>> of catching the lack of dependency checking here. I may take a closer look >>>> later but preferably someone familiar with the build system would take >>>> care of it. >>> >>> If KDTRACE_HOOKS is meant to be kept optional, the hooks should not be >>> compiled in and the functions to enable that feature should return >>> failure, IMHO. >> >> A clarification: The above was of course meant for the case that the >> option has not been specified. It has been activated, I do not expect >> the enable function to return failure ... >> > Try https://reviews.freebsd.org/D23699 That version fixed the issues for me - kernel and world could be built and installed using the previously broken configuration. Thank you for the quick fix. Regards, STefanhelp
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