On Fri, Feb 20, 2026 at 10:57:51AM +0000, [email protected] wrote:
> > diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
> > --- a/kernel/bpf/trampoline.c
> > +++ b/kernel/bpf/trampoline.c
>
> [ ... ]
>
> > @@ -71,7 +110,7 @@ static int bpf_tramp_ftrace_ops_func(struct ftrace_ops
> > *ops, unsigned long ip,
> > /* This is called inside register_ftrace_direct_multi(), so
> > * tr->mutex is already locked.
> > */
> > - lockdep_assert_held_once(&tr->mutex);
> > + lockdep_assert_held_once(trampoline_locks_lookup(tr));
>
> This comment still references tr->mutex, but the field was removed from
> struct bpf_trampoline by this patch. Should the comment say the
> trampoline pool lock is already held instead?
yes, I overlooked the comments..
>
> [ ... ]
>
> > @@ -102,7 +141,7 @@ static int bpf_tramp_ftrace_ops_func(struct ftrace_ops
> > *ops, unsigned long ip,
> > /* The normal locking order is
> > * tr->mutex => direct_mutex (ftrace.c) => ftrace_lock (ftrace.c)
> > *
> > * The following two commands are called from
> > *
> > * prepare_direct_functions_for_ipmodify
> > * cleanup_direct_functions_after_ipmodify
> > *
> > * In both cases, direct_mutex is already locked. Use
> > * mutex_trylock(&tr->mutex) to avoid deadlock in race condition
> > * (something else is making changes to this same trampoline).
> > */
> > - if (!mutex_trylock(&tr->mutex)) {
> > + if (!mutex_trylock(trampoline_locks_lookup(tr))) {
> > /* sleep 1 ms to make sure whatever holding tr->mutex makes
> > * some progress.
> > */
>
> The locking order comment and the two references to tr->mutex in this
> block also appear to need updating. The locking order is now pool lock
> rather than tr->mutex, and the trylock and sleep comments still name the
> removed field.
yes, will fix
>
> [ ... ]
>
> > @@ -1026,11 +1065,11 @@ struct bpf_attach_target_info tgt_info = {};
> > /* note, we're still holding tr refcnt from above */
> >
> > - mutex_unlock(&tr->mutex);
> > + trampoline_unlock(tr);
> >
> > return 0;
> > err:
> > - mutex_unlock(&tr->mutex);
> > + trampoline_unlock(tr);
> >
> > if (shim_link)
> > bpf_link_put(&shim_link->link.link);
> >
> > /* have to release tr while _not_ holding its mutex */
> > bpf_trampoline_put(tr); /* bpf_trampoline_get above */
>
> Similarly, this comment in bpf_trampoline_link_cgroup_shim() references
> "its mutex" which no longer exists as a per-trampoline field.
right, will fix
thanks,
jirka
