From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793207139; b=xRnm9B0LKwgh+KVX8okSkCeo8L3ns1J2XnPyJ7fQKLdUgfmpgk2ByoP3SNhZDbBrTGja O4OPI2uClMgovtjjnEy6g9ZVo0q1KWir20A6AdNAlrubXUYG76DukeuhtPUPqYrJENt1Z KQwqjJE+yorSJsX3Vrd+XmtmAJ/dqKMVlrxxShti2F8aGhoVh4pWdN67t6EJMUUZXIkw0 sVRhEdMH5ZCmFk82wR5LsbiRsewxY6bDiy9Fa6jSvi40sD69PWPIc1dQfZgUxoTXss4mY YIaw2+qnWgJwrxv7I65PsE87YyfviWPzK1O09A3ZcwRHbIMJ5XxCG3dDnqygHNtSTtg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793207139; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=qczC8NT5iKEu0knEzNehkzwq+9Cuh2Tr4rOjtJtVXCE=; b=gqCJtK8dKCiu2DH4EygZoCF83akRigbSLiD8sxaf6nhLK6JQUI7LdU3UpYdT6KmzY6GX nuBxmBy5zE7iK5eDhqov3ykqjs6hMF9Nm+oz7pjGgMK7b/CVNyCV2yNHrxwP5R/TQMuNm 8Niz7Qc5HmzMA9N4HMUylvtLzILS7P0X0g6A0Ocr6ewRLejhnadRKK9cslgP7X8xZqOnx FQjMaZhA6BRBx/Iy3VKdprx9H+q+vQDEofSLkrUhLLSoD65qayX7IdFgIiKKRzfkbF1RS AX4mi9kpDFTx4OFz8teOrjYZ8jgon8t2TdjKRnIJCj6R0GRGDLRebMLwE+tgs5L4gFA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=F9tLsKx2; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5DC71606A321; Wed, 28 Oct 2026 17:05:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=F9tLsKx2 Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF4451F01825; Wed, 28 Oct 2026 17:05:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793207139; bh=qczC8NT5iKEu0knEzNehkzwq+9Cuh2Tr4rOjtJtVXCE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=F9tLsKx2zj7zZe95DW5o9fnmp0jJkmB99mMfA+z/120E7AJge2eOJ4EGlfOuXc2Wq bwlyPQ2Fpm4pHf0RSzK7c+r+ArDJkT3cmpI+38yFDiNvn+m+uB5+cvfrJsd8EewkHy vjHl8pFZY7s5EECet89TaDHhgpj0rJeOCdFAkRHI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Carlier , Steven Rostedt Subject: [PATCH 7.3 06/38] tracing: Hold trace_types_lock when resetting last boot data from readers Date: Wed, 28 Oct 2026 17:59:53 +0100 Message-ID: <20261028165940.565184381@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165940.394092994@linuxfoundation.org> References: <20261028165940.394092994@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Carlier commit 5a6bd62f09147b49b31fd19d4eba122cb5f941a1 upstream. update_last_data_if_empty() is called from tracing_open() with O_TRUNC, tracing_read_pipe() and tracing_buffers_read() without trace_types_lock. Two readers can both pass the LAST_BOOT test and free module_delta twice, and a module notifier can update module_delta while it is being freed. Take trace_types_lock in those paths and keep the callers that already hold it on an unlocked variant. Cc: stable@vger.kernel.org Fixes: 32dc0042528d ("tracing: Reset last-boot buffers when reading out all cpu buffers") Link: https://patch.msgid.link/20261016061638.214847-2-devnexen@gmail.com Signed-off-by: David Carlier Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3614,6 +3614,7 @@ static int tracing_single_release_tr(str return single_release(inode, file); } +static bool __update_last_data_if_empty(struct trace_array *tr); static bool update_last_data_if_empty(struct trace_array *tr); static int tracing_open(struct inode *inode, struct file *file) @@ -4708,7 +4709,7 @@ tracing_set_trace_read(struct file *filp int tracer_init(struct tracer *t, struct trace_array *tr) { tracing_reset_online_cpus(&tr->array_buffer); - update_last_data_if_empty(tr); + __update_last_data_if_empty(tr); return t->init(tr); } @@ -5387,8 +5388,10 @@ static int tracing_wait_pipe(struct file return 1; } -static bool update_last_data_if_empty(struct trace_array *tr) +static bool __update_last_data_if_empty(struct trace_array *tr) { + lockdep_assert_held(&trace_types_lock); + if (!(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) return false; @@ -5403,6 +5406,16 @@ static bool update_last_data_if_empty(st return true; } +static bool update_last_data_if_empty(struct trace_array *tr) +{ + /* Avoid the lock on the read path unless this is a last boot buffer */ + if (!(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) + return false; + + guard(mutex)(&trace_types_lock); + return __update_last_data_if_empty(tr); +} + /* * Consumer reader. */ @@ -6495,7 +6508,7 @@ int tracing_set_clock(struct trace_array ring_buffer_set_clock(tr->snapshot_buffer.buffer, trace_clocks[i].func); tracing_reset_online_cpus(&tr->snapshot_buffer); #endif - update_last_data_if_empty(tr); + __update_last_data_if_empty(tr); if (tr->scratch && !(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) { struct trace_scratch *tscratch = tr->scratch;