From nobody Sat Feb 7 07:31:41 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C126331690A; Tue, 30 Dec 2025 14:51:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767106272; cv=none; b=c4Q/Z0LdObXFlTWiEreb2Prbwxgv3tZQud/l+q6+EFfxjOxcSONmSxESQIHMP8uCGlly/mYXmNIFi4iLlKCY8wBXUUguOwiBPIyEUJr00nNIMkmIhG5MwHTdkSposeLnQZlECMK3UH1ZqC8hu0odxMYOD4xgRzAaJ5KXAtWv6m0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767106272; c=relaxed/simple; bh=3UKM0kw1EtWMFlDFQ1Qvy2lN1AtSkYlGoVhjsmE0TqM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=n9VCoeaW5t/n0mh1vVYMav52Me8U+IuGFFNGApVHJXSItcALO/p1RCcm96aylB2Wz72b6dyJZodb8FmLrWnvLRqv8YhQkI7blK+iF+mmlcysyr/uZJgVKXn7SYcCi6Tcx/hp5usOStSzs0tei95gIj9+YEKHFe+5a66P/W4Z1lE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TkY5645S; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TkY5645S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4150FC19422; Tue, 30 Dec 2025 14:51:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767106272; bh=3UKM0kw1EtWMFlDFQ1Qvy2lN1AtSkYlGoVhjsmE0TqM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TkY5645S3Ez9H117822O6ikO1jbuxx643qMIaVT0/7H1Ix3Jz+8BTutdur7ahOOQu XKctShpCl98n1VNVtlCPwuQFX2IMy+samTtc5kN068Q/A7Cl73HxjotKwkijOiSYZ2 w1rJEXxFEMS2V5ov4kQcet+LENx7WhU1l0SF1zZpl1bM2Xe7iExIC85ykNcdCSUn6+ 4Wn3Q//mTJZ91wbLmwcCKeENPuW2N3RLOKiPTWOAzHmMw9fh6vxLMFlimMESzocWAa yTIH6IGwet4UbrE78olZ6VtIV9xmosvIhSjv41Nhk/XuwKcbVO+vBBCEuWESHZSh7p Es16mGXIzd+GQ== From: Jiri Olsa To: Steven Rostedt , Florent Revest , Mark Rutland Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Menglong Dong , Song Liu Subject: [PATCHv6 bpf-next 5/9] ftrace: Add update_ftrace_direct_del function Date: Tue, 30 Dec 2025 15:50:06 +0100 Message-ID: <20251230145010.103439-6-jolsa@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251230145010.103439-1-jolsa@kernel.org> References: <20251230145010.103439-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Adding update_ftrace_direct_del function that removes all entries (ip -> addr) provided in hash argument to direct ftrace ops and updates its attachments. The difference to current unregister_ftrace_direct is - hash argument that allows to unregister multiple ip -> direct entries at once - we can call update_ftrace_direct_del multiple times on the same ftrace_ops object, becase we do not need to unregister all entries at once, we can do it gradualy with the help of ftrace_update_ops function This change will allow us to have simple ftrace_ops for all bpf direct interface users in following changes. Signed-off-by: Jiri Olsa --- include/linux/ftrace.h | 6 ++ kernel/trace/ftrace.c | 127 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 133 insertions(+) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index f0fcff389061..a3cc1b48c9fc 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -544,6 +544,7 @@ int modify_ftrace_direct(struct ftrace_ops *ops, unsign= ed long addr); int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr= ); =20 int update_ftrace_direct_add(struct ftrace_ops *ops, struct ftrace_hash *h= ash); +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *h= ash); =20 void ftrace_stub_direct_tramp(void); =20 @@ -576,6 +577,11 @@ static inline int update_ftrace_direct_add(struct ftra= ce_ops *ops, struct ftrace return -ENODEV; } =20 +static inline int update_ftrace_direct_del(struct ftrace_ops *ops, struct = ftrace_hash *hash) +{ + return -ENODEV; +} + /* * This must be implemented by the architecture. * It is the way the ftrace direct_ops helper, when called diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3d1170da1bb8..8b75166fb223 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6415,6 +6415,133 @@ int update_ftrace_direct_add(struct ftrace_ops *ops= , struct ftrace_hash *hash) return err; } =20 +/** + * hash_sub - substracts @b from @a and returns the result + * @a: struct ftrace_hash object + * @b: struct ftrace_hash object + * + * Returns struct ftrace_hash object on success, NULL on error. + */ +static struct ftrace_hash *hash_sub(struct ftrace_hash *a, struct ftrace_h= ash *b) +{ + struct ftrace_func_entry *entry, *del; + struct ftrace_hash *sub; + int size; + + sub =3D alloc_and_copy_ftrace_hash(a->size_bits, a); + if (!sub) + return NULL; + + size =3D 1 << b->size_bits; + for (int i =3D 0; i < size; i++) { + hlist_for_each_entry(entry, &b->buckets[i], hlist) { + del =3D __ftrace_lookup_ip(sub, entry->ip); + if (WARN_ON_ONCE(!del)) { + free_ftrace_hash(sub); + return NULL; + } + remove_hash_entry(sub, del); + kfree(del); + } + } + return sub; +} + +/** + * update_ftrace_direct_del - Updates @ops by removing its direct + * callers provided in @hash + * @ops: The address of the struct ftrace_ops object + * @hash: The address of the struct ftrace_hash object + * + * This is used to delete custom direct callers (ip -> addr) in + * @ops specified via @hash. The @ops will be either unregistered + * updated. + * + * Returns: zero on success. Non zero on error, which includes: + * -EINVAL - The @hash is empty + * -EINVAL - The @ops is not registered + */ +int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *h= ash) +{ + struct ftrace_hash *old_direct_functions =3D NULL; + struct ftrace_hash *new_direct_functions; + struct ftrace_hash *new_filter_hash =3D NULL; + struct ftrace_hash *old_filter_hash; + struct ftrace_func_entry *entry; + struct ftrace_func_entry *del; + unsigned long size; + int err =3D -EINVAL; + + if (!hash_count(hash)) + return -EINVAL; + if (check_direct_multi(ops)) + return -EINVAL; + if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) + return -EINVAL; + if (direct_functions =3D=3D EMPTY_HASH) + return -EINVAL; + + mutex_lock(&direct_mutex); + + old_filter_hash =3D ops->func_hash ? ops->func_hash->filter_hash : NULL; + + if (!hash_count(old_filter_hash)) + goto out_unlock; + + /* Make sure requested entries are already registered. */ + size =3D 1 << hash->size_bits; + for (int i =3D 0; i < size; i++) { + hlist_for_each_entry(entry, &hash->buckets[i], hlist) { + del =3D __ftrace_lookup_ip(direct_functions, entry->ip); + if (!del || del->direct !=3D entry->direct) + goto out_unlock; + } + } + + err =3D -ENOMEM; + new_filter_hash =3D hash_sub(old_filter_hash, hash); + if (!new_filter_hash) + goto out_unlock; + + new_direct_functions =3D hash_sub(direct_functions, hash); + if (!new_direct_functions) + goto out_unlock; + + /* If there's nothing left, we need to unregister the ops. */ + if (ftrace_hash_empty(new_filter_hash)) { + err =3D unregister_ftrace_function(ops); + if (!err) { + /* cleanup for possible another register call */ + ops->func =3D NULL; + ops->trampoline =3D 0; + ftrace_free_filter(ops); + ops->func_hash->filter_hash =3D NULL; + } + } else { + err =3D ftrace_update_ops(ops, new_filter_hash, EMPTY_HASH); + /* + * new_filter_hash is dup-ed, so we need to release it anyway, + * old_filter_hash either stays on error or is already released + */ + } + + if (err) { + /* free the new_direct_functions */ + old_direct_functions =3D new_direct_functions; + } else { + rcu_assign_pointer(direct_functions, new_direct_functions); + } + + out_unlock: + mutex_unlock(&direct_mutex); + + if (old_direct_functions && old_direct_functions !=3D EMPTY_HASH) + call_rcu_tasks(&old_direct_functions->rcu, register_ftrace_direct_cb); + free_ftrace_hash(new_filter_hash); + + return err; +} + #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ =20 /** --=20 2.52.0