From 6e4f929ea8b2097b0052f6674de839a3c9d477e9 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 12 Jun 2019 17:15:31 +0200 Subject: [PATCH] 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 Signed-off-by: Borislav Petkov Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-edac Cc: Thomas Gleixner Cc: Tony Luck Cc: x86-ml Link: https://lkml.kernel.org/r/20190612151531.GA16278@kroah.com --- arch/x86/kernel/cpu/mce/core.c | 16 +++++----------- arch/x86/kernel/cpu/mce/inject.c | 37 +++++-------------------------------- arch/x86/kernel/cpu/mce/severity.c | 14 +++----------- 3 files changed, 13 insertions(+), 54 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index c2c93e9..066562a 100644 --- 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 5d108f7..1f30117 100644 --- 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 65201e1..27fd681 100644 --- 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 */ -- 2.7.4