76 lines
2.6 KiB
Diff
76 lines
2.6 KiB
Diff
From 576b70e92168f38ab3167768acb6b65cd5bf8aa7 Mon Sep 17 00:00:00 2001
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From: Charalampos Mitrodimas <charmitro@posteo.net>
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Date: Sat, 16 Aug 2025 14:14:37 +0000
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Subject: debugfs: fix mount options not being applied
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Mount options (uid, gid, mode) are silently ignored when debugfs is
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mounted. This is a regression introduced during the conversion to the
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new mount API.
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When the mount API conversion was done, the parsed options were never
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applied to the superblock when it was reused. As a result, the mount
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options were ignored when debugfs was mounted.
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Fix this by following the same pattern as the tracefs fix in commit
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e4d32142d1de ("tracing: Fix tracefs mount options"). Call
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debugfs_reconfigure() in debugfs_get_tree() to apply the mount options
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to the superblock after it has been created or reused.
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As an example, with the bug the "mode" mount option is ignored:
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$ mount -o mode=0666 -t debugfs debugfs /tmp/debugfs_test
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$ mount | grep debugfs_test
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debugfs on /tmp/debugfs_test type debugfs (rw,relatime)
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$ ls -ld /tmp/debugfs_test
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drwx------ 25 root root 0 Aug 4 14:16 /tmp/debugfs_test
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With the fix applied, it works as expected:
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$ mount -o mode=0666 -t debugfs debugfs /tmp/debugfs_test
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$ mount | grep debugfs_test
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debugfs on /tmp/debugfs_test type debugfs (rw,relatime,mode=666)
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$ ls -ld /tmp/debugfs_test
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drw-rw-rw- 37 root root 0 Aug 2 17:28 /tmp/debugfs_test
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Fixes: a20971c18752 ("vfs: Convert debugfs to use the new mount API")
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Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220406
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Cc: stable <stable@kernel.org>
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Reviewed-by: Eric Sandeen <sandeen@redhat.com>
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Signed-off-by: Charalampos Mitrodimas <charmitro@posteo.net>
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Link: https://lore.kernel.org/r/20250816-debugfs-mount-opts-v3-1-d271dad57b5b@posteo.net
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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fs/debugfs/inode.c | 11 ++++++++++-
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1 file changed, 10 insertions(+), 1 deletion(-)
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--- a/fs/debugfs/inode.c
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+++ b/fs/debugfs/inode.c
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@@ -183,6 +183,9 @@ static int debugfs_reconfigure(struct fs
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struct debugfs_fs_info *sb_opts = sb->s_fs_info;
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struct debugfs_fs_info *new_opts = fc->s_fs_info;
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+ if (!new_opts)
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+ return 0;
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+
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sync_filesystem(sb);
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/* structure copy of new mount options to sb */
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@@ -282,10 +285,16 @@ static int debugfs_fill_super(struct sup
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static int debugfs_get_tree(struct fs_context *fc)
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{
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+ int err;
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+
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if (!(debugfs_allow & DEBUGFS_ALLOW_API))
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return -EPERM;
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- return get_tree_single(fc, debugfs_fill_super);
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+ err = get_tree_single(fc, debugfs_fill_super);
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+ if (err)
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+ return err;
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+
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+ return debugfs_reconfigure(fc);
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}
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static void debugfs_free_fc(struct fs_context *fc)
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