HWPOISON: add an interface to switch off/on all the page filters

In some use cases, user doesn't need extra filtering. E.g. user program
can inject errors through madvise syscall to its own pages, however it
might not know what the page state exactly is or which inode the page
belongs to.

So introduce an one-off interface "corrupt-filter-enable".

Echo 0 to switch off page filters, and echo 1 to switch on the filters.
[AK: changed default to 0]

Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index c838735ac31d5772ec720db39b95c45efe4eac18..c597f46ac18af206d88d72a48087b242effcb7c3 100644 (file)
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -92,6 +92,11 @@ static int pfn_inject_init(void)
        if (!dentry)
                goto fail;
 
+       dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
+                                   hwpoison_dir, &hwpoison_filter_enable);
+       if (!dentry)
+               goto fail;
+
        dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
                                    hwpoison_dir, &hwpoison_filter_dev_major);
        if (!dentry)

diff --git a/mm/internal.h b/mm/internal.h
index 5a6761bea6a693b6b5ae1ef0dddcf84057a665b9..6a697bb97fc589fcdd71ad56a61d43f88862786b 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -258,3 +258,4 @@ extern u32 hwpoison_filter_dev_minor;
 extern u64 hwpoison_filter_flags_mask;
 extern u64 hwpoison_filter_flags_value;
 extern u64 hwpoison_filter_memcg;
+extern u32 hwpoison_filter_enable;

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 117ef15984696377999f22fba89ed3f452499cc0..2d5f1223bf4d4a4640619104a50772a271fa08b2 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -49,10 +49,12 @@ int sysctl_memory_failure_recovery __read_mostly = 1;
 
 atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);
 
+u32 hwpoison_filter_enable = 0;
 u32 hwpoison_filter_dev_major = ~0U;
 u32 hwpoison_filter_dev_minor = ~0U;
 u64 hwpoison_filter_flags_mask;
 u64 hwpoison_filter_flags_value;
+EXPORT_SYMBOL_GPL(hwpoison_filter_enable);
 EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);
 EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);
 EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask);
@@ -145,6 +147,9 @@ static int hwpoison_filter_task(struct page *p) { return 0; }
 
 int hwpoison_filter(struct page *p)
 {
+       if (!hwpoison_filter_enable)
+               return 0;
+
        if (hwpoison_filter_dev(p))
                return -EINVAL;