From: David Carlier <devnexen@gmail.com>
To: rostedt@goodmis.org, mhiramat@kernel.org
Cc: mathieu.desnoyers@efficios.com, kaleshsingh@google.com,
linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, David Carlier <devnexen@gmail.com>
Subject: [PATCH] tracefs: fix default permissions not being applied on initial mount
Date: Sat, 4 Apr 2026 14:47:47 +0100 [thread overview]
Message-ID: <20260404134747.98867-1-devnexen@gmail.com> (raw)
Commit e4d32142d1de ("tracing: Fix tracefs mount options") moved the
option application from tracefs_fill_super() to tracefs_reconfigure()
called from tracefs_get_tree(). This fixed mount options being ignored
on user-space mounts when the superblock already exists, but introduced
a regression for the initial kernel-internal mount.
On the first mount (via simple_pin_fs during init), sget_fc() transfers
fc->s_fs_info to sb->s_fs_info and sets fc->s_fs_info to NULL. When
tracefs_get_tree() then calls tracefs_reconfigure(), it sees a NULL
fc->s_fs_info and returns early without applying any options. The root
inode keeps mode 0755 from simple_fill_super() instead of the intended
TRACEFS_DEFAULT_MODE (0700).
Furthermore, even on subsequent user-space mounts without an explicit
mode= option, tracefs_apply_options(sb, true) gates the mode behind
fsi->opts & BIT(Opt_mode), which is unset for the defaults. So the
mode is never corrected unless the user explicitly passes mode=0700.
Restore the tracefs_apply_options(sb, false) call in tracefs_fill_super()
to apply default permissions on initial superblock creation, matching
what debugfs does in debugfs_fill_super().
Fixes: e4d32142d1de ("tracing: Fix tracefs mount options")
Cc: stable@vger.kernel.org
Signed-off-by: David Carlier <devnexen@gmail.com>
---
fs/tracefs/inode.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index edfdf139cb02..36058ba5ee48 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -491,6 +491,7 @@ static int tracefs_fill_super(struct super_block *sb, struct fs_context *fc)
return err;
sb->s_op = &tracefs_super_operations;
+ tracefs_apply_options(sb, false);
set_default_d_op(sb, &tracefs_dentry_operations);
return 0;
--
2.53.0
reply other threads:[~2026-04-04 13:47 UTC|newest]
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