ddebug_remove_module() use mod->name to find the ddebug_table of the
module and remove it. But dynamic_debug_setup() use the first
_ddebug->modname to create ddebug_table for the module. It's ok when
the _ddebug->modname is the same with the mod->name.
But livepatch module is special, it may contain _ddebugs of other
modules, the modname of which is different from the name of livepatch
module. So ddebug_remove_module() can't use mod->name to find the
right ddebug_table and remove it. It can cause kernel crash when we cat
the file <debugfs>/dynamic_debug/control.
Signed-off-by: Zhou Chengming <[email protected]>
---
kernel/module.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 4a3665f..dac9805 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2703,21 +2703,21 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
}
#endif /* CONFIG_KALLSYMS */
-static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)
+static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num)
{
if (!debug)
return;
#ifdef CONFIG_DYNAMIC_DEBUG
- if (ddebug_add_module(debug, num, debug->modname))
+ if (ddebug_add_module(debug, num, mod->name))
pr_err("dynamic debug error adding module: %s\n",
debug->modname);
#endif
}
-static void dynamic_debug_remove(struct _ddebug *debug)
+static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug)
{
if (debug)
- ddebug_remove_module(debug->modname);
+ ddebug_remove_module(mod->name);
}
void * __weak module_alloc(unsigned long size)
@@ -3697,7 +3697,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
goto free_arch_cleanup;
}
- dynamic_debug_setup(info->debug, info->num_debug);
+ dynamic_debug_setup(mod, info->debug, info->num_debug);
/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
ftrace_module_init(mod);
@@ -3761,7 +3761,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
module_disable_nx(mod);
ddebug_cleanup:
- dynamic_debug_remove(info->debug);
+ dynamic_debug_remove(mod, info->debug);
synchronize_sched();
kfree(mod->args);
free_arch_cleanup:
--
1.8.3.1
+++ Zhou Chengming [07/07/17 11:15 +0800]:
>ddebug_remove_module() use mod->name to find the ddebug_table of the
>module and remove it. But dynamic_debug_setup() use the first
>_ddebug->modname to create ddebug_table for the module. It's ok when
>the _ddebug->modname is the same with the mod->name.
>
>But livepatch module is special, it may contain _ddebugs of other
>modules, the modname of which is different from the name of livepatch
>module. So ddebug_remove_module() can't use mod->name to find the
s/mod->name/_ddebug->modname/ :) I'll fix the typo in the changelog.
>right ddebug_table and remove it. It can cause kernel crash when we cat
>the file <debugfs>/dynamic_debug/control.
>
>Signed-off-by: Zhou Chengming <[email protected]>
Makes sense, I have this queued up to be applied to modules-next.
By the way, although I can see how livepatch modules can end up
including a hodgepodge of _ddebug entries from different modules,
wouldn't the correct thing to do be to have the modname of the
livepatch module instead of the modules they originally came from? I
think when the pr_debug's are enabled it'll print the name of the
original module instead of the livepatch module.
Jessica
> kernel/module.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
>diff --git a/kernel/module.c b/kernel/module.c
>index 4a3665f..dac9805 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -2703,21 +2703,21 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
> }
> #endif /* CONFIG_KALLSYMS */
>
>-static void dynamic_debug_setup(struct _ddebug *debug, unsigned int num)
>+static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num)
> {
> if (!debug)
> return;
> #ifdef CONFIG_DYNAMIC_DEBUG
>- if (ddebug_add_module(debug, num, debug->modname))
>+ if (ddebug_add_module(debug, num, mod->name))
> pr_err("dynamic debug error adding module: %s\n",
> debug->modname);
> #endif
> }
>
>-static void dynamic_debug_remove(struct _ddebug *debug)
>+static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug)
> {
> if (debug)
>- ddebug_remove_module(debug->modname);
>+ ddebug_remove_module(mod->name);
> }
>
> void * __weak module_alloc(unsigned long size)
>@@ -3697,7 +3697,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
> goto free_arch_cleanup;
> }
>
>- dynamic_debug_setup(info->debug, info->num_debug);
>+ dynamic_debug_setup(mod, info->debug, info->num_debug);
>
> /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
> ftrace_module_init(mod);
>@@ -3761,7 +3761,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
> module_disable_nx(mod);
>
> ddebug_cleanup:
>- dynamic_debug_remove(info->debug);
>+ dynamic_debug_remove(mod, info->debug);
> synchronize_sched();
> kfree(mod->args);
> free_arch_cleanup:
>--
>1.8.3.1
>