* Sasha Levin <sasha.levin@xxxxxxxxxx> wrote:
> We can rather easily make lockdep work from userspace, although 3 issues
> remain which I'm not sure about:
>
> - Kernel naming - we can just wrap init_utsname() to return kvmtool related
> utsname, is that what we want though?
>
> - static_obj() - I don't have a better idea than calling mprobe(), which sounds
> wrong as well.
>
> - debug_show_all_locks() - we don't actually call it from userspace yet, but I think
> we might want to, so I'm not sure how to make it pretty using existing kernel code.
>
> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
> ---
> kernel/lockdep.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/lockdep.c b/kernel/lockdep.c
> index 7981e5b..fdd3670 100644
> --- a/kernel/lockdep.c
> +++ b/kernel/lockdep.c
> @@ -567,10 +567,12 @@ static void lockdep_print_held_locks(struct task_struct *curr)
>
> static void print_kernel_ident(void)
> {
> +#ifdef __KERNEL__
> printk("%s %.*s %s\n", init_utsname()->release,
> (int)strcspn(init_utsname()->version, " "),
> init_utsname()->version,
> print_tainted());
> +#endif
I guess wrapping init_utsname() is not worth it. Although
kvmtool could provide the host system's utsname - kernel
identity is useful for debugging info.
You could generate a Git hash version string like tools/perf/
does (see PERF_VERSION and tools/perf/util/PERF-VERSION-GEN),
and put that into the ->version field.
->release could be the kvmtool version, and print_tainted()
could return an empty string.
That way you could provide init_utsname() and could remove this
#ifdef.
> }
>
> static int very_verbose(struct lock_class *class)
> @@ -586,6 +588,7 @@ static int very_verbose(struct lock_class *class)
> */
> static int static_obj(void *obj)
> {
> +#ifdef __KERNEL__
> unsigned long start = (unsigned long) &_stext,
> end = (unsigned long) &_end,
> addr = (unsigned long) obj;
> @@ -609,6 +612,8 @@ static int static_obj(void *obj)
> * module static or percpu var?
> */
> return is_module_address(addr) || is_module_percpu_address(addr);
> +#endif
> + return 1;
Could you put an:
#ifndef static_obj
around it? Then kvmtool could define its own trivial version of
static_obj():
#define static_obj(x) 1U
or so.
> @@ -4108,7 +4113,7 @@ void debug_check_no_locks_held(struct task_struct *task)
> if (unlikely(task->lockdep_depth > 0))
> print_held_locks_bug(task);
> }
> -
> +#ifdef __KERNEL__
> void debug_show_all_locks(void)
> {
> struct task_struct *g, *p;
I guess a show-all-locks functionality would be useful to
kvmtool as well?
Thanks,
Ingo
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