Commit b42bc9a3 authored by Domenico Andreoli's avatar Domenico Andreoli Committed by Linus Torvalds
Browse files

Fix regression due to "fs: move binfmt_misc sysctl to its own file" 



Commit 3ba442d5 ("fs: move binfmt_misc sysctl to its own file") did
not go unnoticed, binfmt-support stopped to work on my Debian system
since v5.17-rc2 (did not check with -rc1).

The existance of the /proc/sys/fs/binfmt_misc is a precondition for
attempting to mount the binfmt_misc fs, which in turn triggers the
autoload of the binfmt_misc module.  Without it, no module is loaded and
no binfmt is available at boot.

Building as built-in or manually loading the module and mounting the fs
works fine, it's therefore only a matter of interaction with user-space.
I could try to improve the Debian systemd configuration but I can't say
anything about the other distributions.

This patch restores a working system right after boot.

Fixes: 3ba442d5 ("fs: move binfmt_misc sysctl to its own file")
Signed-off-by: default avatarDomenico Andreoli <domenico.andreoli@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: default avatarTong Zhang <ztong0001@gmail.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 09a93c1d

fs/binfmt_misc.c

+1 −5
Original line number Diff line number Diff line
@@ -817,20 +817,16 @@ static struct file_system_type bm_fs_type = { 
};

MODULE_ALIAS_FS("binfmt_misc");



static struct ctl_table_header *binfmt_misc_header;



static int __init init_misc_binfmt(void)

{

	int err = register_filesystem(&bm_fs_type);

	if (!err)

		insert_binfmt(&misc_format);

	binfmt_misc_header = register_sysctl_mount_point("fs/binfmt_misc");

	return 0;

	return err;

}



static void __exit exit_misc_binfmt(void)

{

	unregister_sysctl_table(binfmt_misc_header);

	unregister_binfmt(&misc_format);

	unregister_filesystem(&bm_fs_type);

}

fs/file_table.c

+2 −0
Original line number Diff line number Diff line
@@ -119,6 +119,8 @@ static struct ctl_table fs_stat_sysctls[] = { 
static int __init init_fs_stat_sysctls(void)

{

	register_sysctl_init("fs", fs_stat_sysctls);

	if (IS_ENABLED(CONFIG_BINFMT_MISC))

		register_sysctl_mount_point("fs/binfmt_misc");

	return 0;

}

fs_initcall(init_fs_stat_sysctls);