From: Marco Elver <elver@google.com>
To: gregkh@linuxfoundation.org, rafael@kernel.org
Cc: paulmck@kernel.org, dvyukov@google.com, glider@google.com,
andreyknvl@google.com, kasan-dev@googlegroups.com,
linux-kernel@vger.kernel.org, Marco Elver <elver@google.com>,
stable <stable@vger.kernel.org>
Subject: [PATCH] kcsan, debugfs: Move debugfs file creation out of early init
Date: Wed, 3 Mar 2021 10:38:45 +0100 [thread overview]
Message-ID: <20210303093845.2743309-1-elver@google.com> (raw)
Commit 56348560d495 ("debugfs: do not attempt to create a new file
before the filesystem is initalized") forbids creating new debugfs files
until debugfs is fully initialized. This breaks KCSAN's debugfs file
creation, which happened at the end of __init().
There is no reason to create the debugfs file during early
initialization. Therefore, move it into a late_initcall() callback.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: stable <stable@vger.kernel.org>
Fixes: 56348560d495 ("debugfs: do not attempt to create a new file before the filesystem is initalized")
Signed-off-by: Marco Elver <elver@google.com>
---
I've marked this for 'stable', since 56348560d495 is also intended for
stable, and would subsequently break KCSAN in all stable kernels where
KCSAN is available (since 5.8).
---
kernel/kcsan/core.c | 2 --
kernel/kcsan/debugfs.c | 4 +++-
kernel/kcsan/kcsan.h | 5 -----
3 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
index 8c3867640c21..45c821d4e8bd 100644
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -644,8 +644,6 @@ void __init kcsan_init(void)
BUG_ON(!in_task());
- kcsan_debugfs_init();
-
for_each_possible_cpu(cpu)
per_cpu(kcsan_rand_state, cpu) = (u32)get_cycles();
diff --git a/kernel/kcsan/debugfs.c b/kernel/kcsan/debugfs.c
index c837ce6c52e6..c1dd02f3be8b 100644
--- a/kernel/kcsan/debugfs.c
+++ b/kernel/kcsan/debugfs.c
@@ -266,7 +266,9 @@ static const struct file_operations debugfs_ops =
.release = single_release
};
-void __init kcsan_debugfs_init(void)
+static void __init kcsan_debugfs_init(void)
{
debugfs_create_file("kcsan", 0644, NULL, NULL, &debugfs_ops);
}
+
+late_initcall(kcsan_debugfs_init);
diff --git a/kernel/kcsan/kcsan.h b/kernel/kcsan/kcsan.h
index 594a5dd4842a..9881099d4179 100644
--- a/kernel/kcsan/kcsan.h
+++ b/kernel/kcsan/kcsan.h
@@ -31,11 +31,6 @@ extern bool kcsan_enabled;
void kcsan_save_irqtrace(struct task_struct *task);
void kcsan_restore_irqtrace(struct task_struct *task);
-/*
- * Initialize debugfs file.
- */
-void kcsan_debugfs_init(void);
-
/*
* Statistics counters displayed via debugfs; should only be modified in
* slow-paths.
--
2.30.1.766.gb4fecdf3b7-goog
next reply other threads:[~2021-03-03 14:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 9:38 Marco Elver [this message]
2021-03-03 9:57 ` [PATCH] kcsan, debugfs: Move debugfs file creation out of early init Greg KH
2021-03-03 10:18 ` Marco Elver
2021-03-03 10:23 ` Greg KH
2021-03-03 10:27 ` Marco Elver
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