From nobody Wed Apr 15 16:24:02 2026 Received: from mail-pj1-f51.google.com (mail-pj1-f51.google.com [209.85.216.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0111F386547 for ; Wed, 4 Mar 2026 07:47:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772610456; cv=none; b=GwYlHjpStJdi66dNCjJ0Zg/qU8DGnC8JO2sFXXEKLF+keqHbCzUvCm4eCB5X0jmLdLMSw6jM+puPr7LMf+Jbmq3y9Btoo9PuNfGm1YHZvn0DqjZW9czuvn5jlGwP1/uU8pBR7s5DG/9/X5BGFFgpHELT0Gws0Wc4r+j65yFxZrs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772610456; c=relaxed/simple; bh=xij/w7IGsHGa0OZ+mD8D9GCI3hfE/hii5pckeZ7EKcg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dtVPX57Ip4c6c6GLQkG3BgjZxl05rDmlqF3GMzIyfHBrROsNq0KWz1QJJpbCTjkvFSNdBkcw/ndCySxoo9AehNnebX1Tk2pc9yWNe//wDLWzwK9JdgLKRSoubJvXG+TrOMa5o6hyYCHDnhr4iYGB1WTlD21q4HNA5Y2JIH1UppI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=QH9TtQTB; arc=none smtp.client-ip=209.85.216.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QH9TtQTB" Received: by mail-pj1-f51.google.com with SMTP id 98e67ed59e1d1-3590042fa8eso3949056a91.1 for ; Tue, 03 Mar 2026 23:47:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1772610450; x=1773215250; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=4RAdqO2lKtYGLna+N0CaieqoPJ8dofo0McAImpjYXR8=; b=QH9TtQTBc7urRW59mULbeHi3KLE5EFNv1YX9TriWcYeHNJfGddaLGBT4UDTGL1VNdI /aRPPZP54PgzdaFoEs9dXbexfOgctqotpnZzOD0Sa5iKs9wJ49oNnb6aFiaVTf2L+rBe labLFM3yK+9ulTrwDE3fHvSxFHojth2ibpl9up5jQBXtSEGW5CbRFJaOad1Nan1pdygx clXrzaOYkc7Ugb1tqCcSo4u9TQbdSl/c/uVeCuPExw2srqFUknLfTwFCRgNqpA0XTJ1+ 57ywf6/wly7qSXauH95f6kf+u/nor4AYXAIvcDc67AvLKyyu7M3TwZVNSoCZx8aETRwm 2e0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772610450; x=1773215250; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=4RAdqO2lKtYGLna+N0CaieqoPJ8dofo0McAImpjYXR8=; b=FgbPm4+YBIMhV7QO76Lg3pQBQZW8e9q3E6y2LSoNM9bfY4xtk35oZLAPmxmIXkkb6B Qzd2k9H7Wl373rs/VUwR3YdATgDxKLxBK97aA24pYj6DAXDgAZqdpsdhzGiWoALvx2CO 9Ii3WEfCBU85XRHxhOoh5FKJmeKYseYVql9evEnNOP+fUX4hTk5iW7NVGePBeeEUorJT guIuYkQ/lU3uy7CNBlaosRArv6KJhGMuwwgPUset8RidwMFGjzqHBp5M/9y6kPxMhdN1 GZt5KKPI+FjVyv3BPt10ejVEQpzUJWMyRB17gsvhEg/h48o5EFCLUxQsMThOiVTYJhLE XxTA== X-Gm-Message-State: AOJu0Yw8hOSAB+7OyrnrDJdyM1LGD4C+hGVcE5qDyIgpoKCfXnRYin8+ Hwot1ijSl1OgWpIjjfKHsM9jiCIICi+juXQeK1Xl4pcMHC5y8uWEmLuM X-Gm-Gg: ATEYQzwIqGiHn0WdOhmc4fXbbu9sCpW8ON9OEGH+t+qDJWXPDD+K4IbGq/wYCy62nGe SqJmsiYspfgeI06LfDl5yv2+r0vwa832yZWPjVRvEw5969zlEXP9DjjBSI8oUb+Xz7cJBcy46Jh h74gm+f1ztrsR4VGAz1gpj+shpXTxWx7RRNkGoz/yUyOqZ8Jnb9+PT4ov7ZJAqx8JpxjGbB2akJ ncELDUjOV7oyIhtHcSQ1e2gj69CGi5LqLyVWXWcjUEFFJ+DnoxCxb2VSM9wd5dHfHqcGpzELFOP TkBAug3xhDn4iC/HNDpjiWgQe7E9omH/wMiYGukbewvJ9w2Oa/no45Fa7YqPgOcNkg0yHUbwlff 7+PTyt6UL8IUN+3KF6IJLSm5G9HJFBB0jNoGmHcV4SABOb0LzyVAH6GzTYYKJDEOpDehiQhqCgI YAvGByi0spEnoRscvRUzeu13Rb/MPH2abZ0BlEbd5DcT1hiK6tkPx7dhB1OtpdYQ== X-Received: by 2002:a17:90b:3c90:b0:359:8c89:96cd with SMTP id 98e67ed59e1d1-359a69dae40mr1105809a91.12.1772610449953; Tue, 03 Mar 2026 23:47:29 -0800 (PST) Received: from localhost.localdomain ([2409:891f:1ba6:a29e:d73:6202:f71f:51b0]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3599c39def7sm4352078a91.12.2026.03.03.23.47.26 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Tue, 03 Mar 2026 23:47:29 -0800 (PST) From: Yafang Shao To: peterz@infradead.org, mingo@redhat.com, will@kernel.org, boqun@kernel.org, longman@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org, mark.rutland@arm.com, mathieu.desnoyers@efficios.com Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, Yafang Shao Subject: [RFC PATCH 2/2] ftrace: disable optimistic spinning for ftrace_lock Date: Wed, 4 Mar 2026 15:46:50 +0800 Message-ID: <20260304074650.58165-3-laoar.shao@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260304074650.58165-1-laoar.shao@gmail.com> References: <20260304074650.58165-1-laoar.shao@gmail.com> 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" mutex_lock_nospin() is used for ftrace_lock to selectively disable optimistic spinning. Signed-off-by: Yafang Shao --- kernel/trace/ftrace.c | 52 +++++++++++++++++++++---------------------- 1 file changed, 26 insertions(+), 26 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 827fb9a0bf0d..b8cca4f76118 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1284,7 +1284,7 @@ static void clear_ftrace_mod_list(struct list_head *h= ead) if (!head) return; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); list_for_each_entry_safe(p, n, head, list) free_ftrace_mod(p); mutex_unlock(&ftrace_lock); @@ -4254,7 +4254,7 @@ static void *t_start(struct seq_file *m, loff_t *pos) void *p =3D NULL; loff_t l; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 if (unlikely(ftrace_disabled)) return NULL; @@ -4362,7 +4362,7 @@ static __init void ftrace_check_work_func(struct work= _struct *work) struct ftrace_page *pg; struct dyn_ftrace *rec; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); do_for_each_ftrace_rec(pg, rec) { test_for_valid_rec(rec); } while_for_each_ftrace_rec(); @@ -5123,7 +5123,7 @@ static void process_mod_list(struct list_head *head, = struct ftrace_ops *ops, if (!new_hash) goto out; /* warn? */ =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 list_for_each_entry_safe(ftrace_mod, n, head, list) { =20 @@ -5159,7 +5159,7 @@ static void process_mod_list(struct list_head *head, = struct ftrace_ops *ops, if (enable && list_empty(head)) new_hash->flags &=3D ~FTRACE_HASH_FL_MOD; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 ftrace_hash_move_and_update_ops(ops, orig_hash, new_hash, enable); @@ -5465,7 +5465,7 @@ register_ftrace_function_probe(char *glob, struct tra= ce_array *tr, return -EINVAL; =20 =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); /* Check if the probe_ops is already registered */ list_for_each_entry(iter, &tr->func_probes, list) { if (iter->probe_ops =3D=3D probe_ops) { @@ -5540,7 +5540,7 @@ register_ftrace_function_probe(char *glob, struct tra= ce_array *tr, } } =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 if (!count) { /* Nothing was added? */ @@ -5619,7 +5619,7 @@ unregister_ftrace_function_probe_func(char *glob, str= uct trace_array *tr, return -EINVAL; } =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); /* Check if the probe_ops is already registered */ list_for_each_entry(iter, &tr->func_probes, list) { if (iter->probe_ops =3D=3D probe_ops) { @@ -5679,7 +5679,7 @@ unregister_ftrace_function_probe_func(char *glob, str= uct trace_array *tr, goto out_unlock; } =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 WARN_ON(probe->ref < count); =20 @@ -5943,7 +5943,7 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char= *buf, int len, goto out_regex_unlock; } =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); ret =3D ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable); mutex_unlock(&ftrace_lock); =20 @@ -6205,7 +6205,7 @@ __modify_ftrace_direct(struct ftrace_ops *ops, unsign= ed long addr) * Now the ftrace_ops_list_func() is called to do the direct callers. * We can safely change the direct functions attached to each entry. */ - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 size =3D 1 << hash->size_bits; for (i =3D 0; i < size; i++) { @@ -6625,7 +6625,7 @@ int update_ftrace_direct_mod(struct ftrace_ops *ops, = struct ftrace_hash *hash, b * Now the ftrace_ops_list_func() is called to do the direct callers. * We can safely change the direct functions attached to each entry. */ - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 size =3D 1 << hash->size_bits; for (i =3D 0; i < size; i++) { @@ -6980,7 +6980,7 @@ int ftrace_regex_release(struct inode *inode, struct = file *file) } else orig_hash =3D &iter->ops->func_hash->notrace_hash; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); ftrace_hash_move_and_update_ops(iter->ops, orig_hash, iter->hash, filter_hash); mutex_unlock(&ftrace_lock); @@ -7464,7 +7464,7 @@ void ftrace_create_filter_files(struct ftrace_ops *op= s, */ void ftrace_destroy_filter_files(struct ftrace_ops *ops) { - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); if (ops->flags & FTRACE_OPS_FL_ENABLED) ftrace_shutdown(ops, 0); ops->flags |=3D FTRACE_OPS_FL_DELETED; @@ -7571,7 +7571,7 @@ static int ftrace_process_locs(struct module *mod, if (!start_pg) return -ENOMEM; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 /* * Core and each module needs their own pages, as @@ -7868,7 +7868,7 @@ void ftrace_release_mod(struct module *mod) struct ftrace_page *tmp_page =3D NULL; struct ftrace_page *pg; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 /* * To avoid the UAF problem after the module is unloaded, the @@ -7938,7 +7938,7 @@ void ftrace_module_enable(struct module *mod) struct dyn_ftrace *rec; struct ftrace_page *pg; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 if (ftrace_disabled) goto out_unlock; @@ -8267,7 +8267,7 @@ void ftrace_free_mem(struct module *mod, void *start_= ptr, void *end_ptr) key.ip =3D start; key.flags =3D end; /* overload flags, as it is unsigned long */ =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 /* * If we are freeing module init memory, then check if @@ -8686,7 +8686,7 @@ static void clear_ftrace_pids(struct trace_array *tr,= int type) =20 void ftrace_clear_pids(struct trace_array *tr) { - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS); =20 @@ -8695,7 +8695,7 @@ void ftrace_clear_pids(struct trace_array *tr) =20 static void ftrace_pid_reset(struct trace_array *tr, int type) { - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); clear_ftrace_pids(tr, type); =20 ftrace_update_pid_func(); @@ -8713,7 +8713,7 @@ static void *fpid_start(struct seq_file *m, loff_t *p= os) struct trace_pid_list *pid_list; struct trace_array *tr =3D m->private; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); rcu_read_lock_sched(); =20 pid_list =3D rcu_dereference_sched(tr->function_pids); @@ -8766,7 +8766,7 @@ static void *fnpid_start(struct seq_file *m, loff_t *= pos) struct trace_pid_list *pid_list; struct trace_array *tr =3D m->private; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); rcu_read_lock_sched(); =20 pid_list =3D rcu_dereference_sched(tr->function_no_pids); @@ -9057,7 +9057,7 @@ static int prepare_direct_functions_for_ipmodify(stru= ct ftrace_ops *ops) unsigned long ip =3D entry->ip; bool found_op =3D false; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); do_for_each_ftrace_op(op, ftrace_ops_list) { if (!(op->flags & FTRACE_OPS_FL_DIRECT)) continue; @@ -9106,7 +9106,7 @@ static void cleanup_direct_functions_after_ipmodify(s= truct ftrace_ops *ops) unsigned long ip =3D entry->ip; bool found_op =3D false; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); do_for_each_ftrace_op(op, ftrace_ops_list) { if (!(op->flags & FTRACE_OPS_FL_DIRECT)) continue; @@ -9153,7 +9153,7 @@ static int register_ftrace_function_nolock(struct ftr= ace_ops *ops) =20 ftrace_ops_init(ops); =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); =20 ret =3D ftrace_startup(ops, 0); =20 @@ -9200,7 +9200,7 @@ int unregister_ftrace_function(struct ftrace_ops *ops) { int ret; =20 - mutex_lock(&ftrace_lock); + mutex_lock_nospin(&ftrace_lock); ret =3D ftrace_shutdown(ops, 0); mutex_unlock(&ftrace_lock); =20 --=20 2.47.3