Date: Sun, 2 Jul 2023 02:13:16 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Ka Ho Ng <khng@freebsd.org> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 005aa1743b42 - main - modules: bzero the modspecific_t Message-ID: <ZKCzDPfJM2gGrhYT@kib.kiev.ua> In-Reply-To: <202307012259.361MxM4i017090@gitrepo.freebsd.org> References: <202307012259.361MxM4i017090@gitrepo.freebsd.org>
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On Sat, Jul 01, 2023 at 10:59:22PM +0000, Ka Ho Ng wrote: > The branch main has been updated by khng: > > URL: https://cgit.FreeBSD.org/src/commit/?id=005aa1743b42b52fbd49b9d5ec44816902b6ee9f > > commit 005aa1743b42b52fbd49b9d5ec44816902b6ee9f > Author: Ka Ho Ng <khng@FreeBSD.org> > AuthorDate: 2023-07-01 19:41:53 +0000 > Commit: Ka Ho Ng <khng@FreeBSD.org> > CommitDate: 2023-07-01 22:58:46 +0000 > > modules: bzero the modspecific_t > > Per https://reviews.llvm.org/D68115, only the first field is > zero-initialized, meanwhile other fields are undef. This is not true. > > The pattern can be observed on clang as well, that when > -ftrivial-auto-var-init=pattern is specified 0xaa is filled for > non-active fields, otherwise they are zero-initialized. What are non-active fields? All fields with implicit initializers "shall be initialized implicitly the same as objects that have static storage duration." I do not think this is required for padding. > Technically both are acceptable when using clang. However it > would be good to simply bzero the modspecific_t in such case to > be strict to the standard. > > MFC with: 2cab2d43b83b > MFC after: 1 day Min MFC period is 3 days. > Sponsored by: Juniper Networks, Inc. > Reviewed by: delphij > Differential Revision: https://reviews.freebsd.org/D40830 > --- > sys/kern/kern_syscalls.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/sys/kern/kern_syscalls.c b/sys/kern/kern_syscalls.c > index 234e51cfd280..0b51edf5e985 100644 > --- a/sys/kern/kern_syscalls.c > +++ b/sys/kern/kern_syscalls.c > @@ -173,9 +173,10 @@ kern_syscall_module_handler(struct sysent *sysents, struct module *mod, > int what, void *arg) > { > struct syscall_module_data *data = arg; > - modspecific_t ms = { 0 }; > + modspecific_t ms; > int error; > > + bzero(&ms, sizeof(ms)); > switch (what) { > case MOD_LOAD: > error = kern_syscall_register(sysents, data->offset,
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