From mboxrd@z Thu Jan 1 00:00:00 1970 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 205BE253351; Tue, 29 Apr 2025 18:15:23 +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=1745950523; cv=none; b=FMnWeCuAo2yMJGvUoG9zlr+MCE/7WPjs2AqXSKfkq61m4TO4nzztVa0AzWexmdTovVoBDqn+k+nwienpxv75CqcBgvNV4EGiwhoRlzt3l3AY8aE/fjj7W4TNJQjPn7pXZ8C5c685x+YxB+arjxS7phe9GC4qgQWbS5K9v2+Qa6k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745950523; c=relaxed/simple; bh=Utd9y3eTbyXSzcBvaU47tAch6VzNtBIf79d8kA7PvPI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NDslY/e77/PMnxODhdmx6QLK+I8PoNUqt7q5X+D/hu4AnzurBAsCcEPd/LYgj+6OsrZE4QYPHiT3+51c5irGj+3akJlvQRIOiQI6pQGQZkD+qKfGkksmk07PCemiE/uosCKViQz0oQzQ5W0yPBcg7Y3czx3BbQ+WOIQmPtmY50k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ruUPorJB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ruUPorJB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90537C4CEEA; Tue, 29 Apr 2025 18:15:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745950523; bh=Utd9y3eTbyXSzcBvaU47tAch6VzNtBIf79d8kA7PvPI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ruUPorJBYfkr6b+yFoIbPESUqREx9NlIbTa4zNVmRG0W3kJxuVkCkpGBpn1vyC9BF u9L+PimFQOMrblAwQivwa8Vqpeo7TSp83Bafl6nnL+8iCEKeTZV9hwo+q2h9UXIDmj gD7w3s8r48lSbzkjYVTp53uXRvbDPXMs5aLFdwUo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexei Starovoitov , Andrii Nakryiko , Sasha Levin Subject: [PATCH 6.6 121/204] bpf: Fix deadlock between rcu_tasks_trace and event_mutex. Date: Tue, 29 Apr 2025 18:43:29 +0200 Message-ID: <20250429161104.384098496@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161059.396852607@linuxfoundation.org> References: <20250429161059.396852607@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexei Starovoitov [ Upstream commit 4580f4e0ebdf8dc8d506ae926b88510395a0c1d1 ] Fix the following deadlock: CPU A _free_event() perf_kprobe_destroy() mutex_lock(&event_mutex) perf_trace_event_unreg() synchronize_rcu_tasks_trace() There are several paths where _free_event() grabs event_mutex and calls sync_rcu_tasks_trace. Above is one such case. CPU B bpf_prog_test_run_syscall() rcu_read_lock_trace() bpf_prog_run_pin_on_cpu() bpf_prog_load() bpf_tracing_func_proto() trace_set_clr_event() mutex_lock(&event_mutex) Delegate trace_set_clr_event() to workqueue to avoid such lock dependency. Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250224221637.4780-1-alexei.starovoitov@gmail.com Signed-off-by: Sasha Levin --- kernel/trace/bpf_trace.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 545393601be8c..97f660a8ddc73 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -400,7 +400,7 @@ static const struct bpf_func_proto bpf_trace_printk_proto = { .arg2_type = ARG_CONST_SIZE, }; -static void __set_printk_clr_event(void) +static void __set_printk_clr_event(struct work_struct *work) { /* * This program might be calling bpf_trace_printk, @@ -413,10 +413,11 @@ static void __set_printk_clr_event(void) if (trace_set_clr_event("bpf_trace", "bpf_trace_printk", 1)) pr_warn_ratelimited("could not enable bpf_trace_printk events"); } +static DECLARE_WORK(set_printk_work, __set_printk_clr_event); const struct bpf_func_proto *bpf_get_trace_printk_proto(void) { - __set_printk_clr_event(); + schedule_work(&set_printk_work); return &bpf_trace_printk_proto; } @@ -459,7 +460,7 @@ static const struct bpf_func_proto bpf_trace_vprintk_proto = { const struct bpf_func_proto *bpf_get_trace_vprintk_proto(void) { - __set_printk_clr_event(); + schedule_work(&set_printk_work); return &bpf_trace_vprintk_proto; } -- 2.39.5