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Groups > linux.kernel > #1261555
| From | Josh Poimboeuf <jpoimboe@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory |
| Date | 2015-11-03 16:00 +0100 |
| Message-ID | <qqLe2-41D-11@gated-at.bofh.it> (permalink) |
| References | <qqu3w-1uH-23@gated-at.bofh.it> <qqwoF-34I-7@gated-at.bofh.it> <qqHtL-1CF-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Nov 03, 2015 at 11:52:08AM +0100, Miroslav Benes wrote:
> On Mon, 2 Nov 2015, Chris J Arges wrote:
>
> [...]
>
> > +static int klp_get_func_pos_callback(void *data, const char *name,
> > + struct module *mod, unsigned long addr)
> > +{
> > + struct klp_find_arg *args = data;
> > +
> > + if ((mod && !args->objname) || (!mod && args->objname))
> > + return 0;
> > +
> > + if (strcmp(args->name, name))
> > + return 0;
> > +
> > + if (args->objname && strcmp(args->objname, mod->name))
> > + return 0;
> > +
> > + /* on address match, return 1 to break kallsyms_on_each_symbol loop */
> > + if (args->addr == addr)
> > + return 1;
> > +
> > + /* if we don't match addr, count instance of named symbol */
> > + args->count++;
> > +
> > + return 0;
> > +}
> > +
> > +static int klp_get_func_pos(struct klp_object *obj, struct klp_func *func)
> > +{
> > + struct klp_find_arg args = {
> > + .objname = obj->name,
> > + .name = func->old_name,
> > + .addr = func->old_addr,
> > + .count = 0,
> > + };
> > +
> > + mutex_lock(&module_mutex);
> > + kallsyms_on_each_symbol(klp_get_func_pos_callback, &args);
> > + mutex_unlock(&module_mutex);
> > +
> > + return args.count;
> > +}
> > +
> > static int klp_init_func(struct klp_object *obj, struct klp_func *func)
> > {
> > INIT_LIST_HEAD(&func->stack_node);
> > func->state = KLP_DISABLED;
> >
> > return kobject_init_and_add(&func->kobj, &klp_ktype_func,
> > - &obj->kobj, "%s", func->old_name);
> > + &obj->kobj, "%s,%d", func->old_name,
> > + klp_get_func_pos(obj, func));
> > }
>
> There is a problem which I missed before. klp_init_func() is called before
> klp_find_verify_func_addr() in klp_init_object(). This means that
> func->old_addr is either not verified yet or worse it is still 0. This
> means that klp_get_func_pos_callback() never returns 1 and is thus called
> on each symbol. So if you for example patched cmdline_proc_show the
> resulting directory in sysfs would be called cmdline_proc_show,1 because
> addr is never matched. Had old_addr been specified the name would have
> been probably correct, but not for sure.
>
> This should be fixed as well.
Even worse, klp_init_func() can be called even if the object hasn't been
loaded. In that case there's no way to know what the value of n is, and
therefore no way to reliably create the sysfs entry.
Should we create "func,n" in klp_init_object_loaded() instead of
klp_init_func()?
--
Josh
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[PATCH] livepatch: old_name.number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-02 19:00 +0100
Re: livepatch: old_name.number scheme in livepatch sysfs directory Jessica Yu <jeyu@redhat.com> - 2015-11-02 20:20 +0100
Re: [PATCH] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-02 21:00 +0100
Re: [PATCH] livepatch: old_name.number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-02 21:20 +0100
Re: [PATCH] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-02 21:40 +0100
[PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-03 00:10 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Miroslav Benes <mbenes@suse.cz> - 2015-11-03 11:00 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-03 16:10 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Miroslav Benes <mbenes@suse.cz> - 2015-11-03 12:00 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Petr Mladek <pmladek@suse.com> - 2015-11-03 13:50 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-03 16:10 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Jiri Kosina <jikos@kernel.org> - 2015-11-03 21:00 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-03 21:10 +0100
[PATCH 1/3 v4] livepatch: add old_sympos as disambiguator field to klp_func Chris J Arges <chris.j.arges@canonical.com> - 2015-11-11 17:30 +0100
Re: [PATCH 1/3 v4] livepatch: add old_sympos as disambiguator field to klp_func Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-11 18:50 +0100
Re: [PATCH 1/3 v4] livepatch: add old_sympos as disambiguator field to klp_func Miroslav Benes <mbenes@suse.cz> - 2015-11-12 11:30 +0100
[PATCH 3/3 v4] livepatch: old_name,number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-11 17:40 +0100
Re: [PATCH 3/3 v4] livepatch: old_name,number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-11 19:10 +0100
Re: [PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Chris J Arges <chris.j.arges@canonical.com> - 2015-11-11 17:40 +0100
[PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Chris J Arges <chris.j.arges@canonical.com> - 2015-11-11 17:40 +0100
Re: [PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-11 19:00 +0100
Re: [PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Petr Mladek <pmladek@suse.com> - 2015-11-12 15:40 +0100
Re: [PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-12 20:20 +0100
Re: [PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Petr Mladek <pmladek@suse.com> - 2015-11-13 15:00 +0100
Re: [PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-13 18:00 +0100
Re: [PATCH 2/3 v4] livepatch: add old_sympos as disambiguator field to klp_reloc Miroslav Benes <mbenes@suse.cz> - 2015-11-12 11:30 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-03 16:00 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Miroslav Benes <mbenes@suse.cz> - 2015-11-03 17:20 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-03 18:00 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-03 21:50 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Miroslav Benes <mbenes@suse.cz> - 2015-11-04 11:00 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-04 17:10 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-04 17:20 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Miroslav Benes <mbenes@suse.cz> - 2015-11-05 16:20 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-05 17:00 +0100
Re: [PATCH v2] livepatch: old_name.number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-05 17:10 +0100
[PATCH v3] livepatch: old_name,number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-09 17:20 +0100
Re: [PATCH v3] livepatch: old_name,number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-09 22:00 +0100
Re: [PATCH v3] livepatch: old_name,number scheme in livepatch sysfs directory Chris J Arges <chris.j.arges@canonical.com> - 2015-11-10 00:10 +0100
Re: [PATCH v3] livepatch: old_name,number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-10 06:00 +0100
Re: [PATCH v3] livepatch: old_name,number scheme in livepatch sysfs directory Miroslav Benes <mbenes@suse.cz> - 2015-11-10 09:50 +0100
Re: [PATCH v3] livepatch: old_name,number scheme in livepatch sysfs directory Josh Poimboeuf <jpoimboe@redhat.com> - 2015-11-10 14:50 +0100
Re: [PATCH v3] livepatch: old_name,number scheme in livepatch sysfs directory Miroslav Benes <mbenes@suse.cz> - 2015-11-10 10:10 +0100
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