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.