x86/mce: Do not check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

The only way this can fail is if:

 * debugfs superblock can not be pinned - something really went wrong with the
 vfs layer.
 * file is created with same name - the caller's fault.
 * new_inode() fails - happens if memory is exhausted.

so failing to clean up debugfs properly is the least of the system's
sproblems in uch a situation.

 [ bp: Extend commit message, remove unused err var in inject_init(). ]

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190612151531.GA16278@kroah.com

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index c2c93e9195ed41e075fa904d914d796c9ed6f1d5..066562a1ea20bf7efa3a5e93d7b1253b412b9427 100644 (file)
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -2516,22 +2516,16 @@ static int fake_panic_set(void *data, u64 val)
 DEFINE_DEBUGFS_ATTRIBUTE(fake_panic_fops, fake_panic_get, fake_panic_set,
                         "%llu\n");
 
-static int __init mcheck_debugfs_init(void)
+static void __init mcheck_debugfs_init(void)
 {
-       struct dentry *dmce, *ffake_panic;
+       struct dentry *dmce;
 
        dmce = mce_get_debugfs_dir();
-       if (!dmce)
-               return -ENOMEM;
-       ffake_panic = debugfs_create_file_unsafe("fake_panic", 0444, dmce,
-                                                NULL, &fake_panic_fops);
-       if (!ffake_panic)
-               return -ENOMEM;
-
-       return 0;
+       debugfs_create_file_unsafe("fake_panic", 0444, dmce, NULL,
+                                  &fake_panic_fops);
 }
 #else
-static int __init mcheck_debugfs_init(void) { return -EINVAL; }
+static void __init mcheck_debugfs_init(void) { }
 #endif
 
 DEFINE_STATIC_KEY_FALSE(mcsafe_key);

diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
index 5d108f70f3151d4ddf805092106170958d64479f..1f30117b24ba7af6220fb8a5001f46b9a536a7db 100644 (file)
--- a/arch/x86/kernel/cpu/mce/inject.c
+++ b/arch/x86/kernel/cpu/mce/inject.c
@@ -645,7 +645,6 @@ static const struct file_operations readme_fops = {
 
 static struct dfs_node {
        char *name;
-       struct dentry *d;
        const struct file_operations *fops;
        umode_t perm;
 } dfs_fls[] = {
@@ -659,49 +658,23 @@ static struct dfs_node {
        { .name = "README",     .fops = &readme_fops, .perm = S_IRUSR | S_IRGRP | S_IROTH },
 };
 
-static int __init debugfs_init(void)
+static void __init debugfs_init(void)
 {
        unsigned int i;
 
        dfs_inj = debugfs_create_dir("mce-inject", NULL);
-       if (!dfs_inj)
-               return -EINVAL;
-
-       for (i = 0; i < ARRAY_SIZE(dfs_fls); i++) {
-               dfs_fls[i].d = debugfs_create_file(dfs_fls[i].name,
-                                                   dfs_fls[i].perm,
-                                                   dfs_inj,
-                                                   &i_mce,
-                                                   dfs_fls[i].fops);
-
-               if (!dfs_fls[i].d)
-                       goto err_dfs_add;
-       }
-
-       return 0;
-
-err_dfs_add:
-       while (i-- > 0)
-               debugfs_remove(dfs_fls[i].d);
 
-       debugfs_remove(dfs_inj);
-       dfs_inj = NULL;
-
-       return -ENODEV;
+       for (i = 0; i < ARRAY_SIZE(dfs_fls); i++)
+               debugfs_create_file(dfs_fls[i].name, dfs_fls[i].perm, dfs_inj,
+                                   &i_mce, dfs_fls[i].fops);
 }
 
 static int __init inject_init(void)
 {
-       int err;
-
        if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
                return -ENOMEM;
 
-       err = debugfs_init();
-       if (err) {
-               free_cpumask_var(mce_inject_cpumask);
-               return err;
-       }
+       debugfs_init();
 
        register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0, "mce_notify");
        mce_register_injector_chain(&inject_nb);

diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 65201e180fe0ee019b7571fc3921a0745a6bdbe1..27fd6816e270059c1b9575b9436df2d2500b8bd5 100644 (file)
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -404,21 +404,13 @@ static const struct file_operations severities_coverage_fops = {
 
 static int __init severities_debugfs_init(void)
 {
-       struct dentry *dmce, *fsev;
+       struct dentry *dmce;
 
        dmce = mce_get_debugfs_dir();
-       if (!dmce)
-               goto err_out;
-
-       fsev = debugfs_create_file("severities-coverage", 0444, dmce, NULL,
-                                  &severities_coverage_fops);
-       if (!fsev)
-               goto err_out;
 
+       debugfs_create_file("severities-coverage", 0444, dmce, NULL,
+                           &severities_coverage_fops);
        return 0;
-
-err_out:
-       return -ENOMEM;
 }
 late_initcall(severities_debugfs_init);
 #endif /* CONFIG_DEBUG_FS */