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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
alistair/sunxi64-5.4-dsi
Greg Kroah-Hartman 2019-06-12 17:15:31 +02:00 committed by Borislav Petkov
parent 068b053dca
commit 6e4f929ea8
3 changed files with 13 additions and 54 deletions
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16
arch/x86/kernel/cpu/mce/core.c
View File

@ -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);

37
arch/x86/kernel/cpu/mce/inject.c
View File

@ -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);

14
arch/x86/kernel/cpu/mce/severity.c
View File

@ -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 */