* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits)
HWPOISON: Enable error_remove_page on btrfs
HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
HWPOISON: Add madvise() based injector for hardware poisoned pages v4
HWPOISON: Enable error_remove_page for NFS
HWPOISON: Enable .remove_error_page for migration aware file systems
HWPOISON: The high level memory error handler in the VM v7
HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
HWPOISON: shmem: call set_page_dirty() with locked page
HWPOISON: Define a new error_remove_page address space op for async truncation
HWPOISON: Add invalidate_inode_page
HWPOISON: Refactor truncate to allow direct truncating of page v2
HWPOISON: check and isolate corrupted free pages v2
HWPOISON: Handle hardware poisoned pages in try_to_unmap
HWPOISON: Use bitmask/action code for try_to_unmap behaviour
HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
HWPOISON: Add poison check to page fault handling
HWPOISON: Add basic support for poisoned pages in fault handler v3
HWPOISON: Add new SIGBUS error codes for hardware poison signals
HWPOISON: Add support for poison swap entries v2
HWPOISON: Export some rmap vma locking to outside world
...
/* migrate the contents of a page to the specified target */
int (*migratepage) (struct page *, struct page *);
int (*launder_page) (struct page *);
+ int (*error_remove_page) (struct mapping *mapping, struct page *page);
};
writepage: called by the VM to write a dirty page to backing store.
prevent redirtying the page, it is kept locked during the whole
operation.
+ error_remove_page: normally set to generic_error_remove_page if truncation
+ is ok for this address space. Used for memory failure handling.
+ Setting this implies you deal with pages going away under you,
+ unless you have them locked or reference counts increased.
+
+
The File Object
===============
- legacy_va_layout
- lowmem_reserve_ratio
- max_map_count
+- memory_failure_early_kill
+- memory_failure_recovery
- min_free_kbytes
- min_slab_ratio
- min_unmapped_ratio
- vfs_cache_pressure
- zone_reclaim_mode
-
==============================================================
block_dump
The default value is 65536.
+=============================================================
+
+memory_failure_early_kill:
+
+Control how to kill processes when uncorrected memory error (typically
+a 2bit error in a memory module) is detected in the background by hardware
+that cannot be handled by the kernel. In some cases (like the page
+still having a valid copy on disk) the kernel will handle the failure
+transparently without affecting any applications. But if there is
+no other uptodate copy of the data it will kill to prevent any data
+corruptions from propagating.
+
+1: Kill all processes that have the corrupted and not reloadable page mapped
+as soon as the corruption is detected. Note this is not supported
+for a few types of pages, like kernel internally allocated data or
+the swap cache, but works for the majority of user pages.
+
+0: Only unmap the corrupted page from all processes and only kill a process
+who tries to access it.
+
+The kill is done using a catchable SIGBUS with BUS_MCEERR_AO, so processes can
+handle this if they want to.
+
+This is only active on architectures/platforms with advanced machine
+check handling and depends on the hardware capabilities.
+
+Applications can override this setting individually with the PR_MCE_KILL prctl
+
+==============================================================
+
+memory_failure_recovery
+
+Enable memory failure recovery (when supported by the platform)
+
+1: Attempt recovery.
+
+0: Always panic on a memory failure.
+
==============================================================
min_free_kbytes:
info.si_errno = 0;
info.si_code = si_code;
info.si_addr = (void __user *)address;
+ info.si_addr_lsb = si_code == BUS_MCEERR_AR ? PAGE_SHIFT : 0;
force_sig_info(si_signo, &info, tsk);
}
}
static void
-do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
+do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
+ unsigned int fault)
{
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
+ int code = BUS_ADRERR;
up_read(&mm->mmap_sem);
tsk->thread.error_code = error_code;
tsk->thread.trap_no = 14;
- force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
+#ifdef CONFIG_MEMORY_FAILURE
+ if (fault & VM_FAULT_HWPOISON) {
+ printk(KERN_ERR
+ "MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",
+ tsk->comm, tsk->pid, address);
+ code = BUS_MCEERR_AR;
+ }
+#endif
+ force_sig_info_fault(SIGBUS, code, address, tsk);
}
static noinline void
if (fault & VM_FAULT_OOM) {
out_of_memory(regs, error_code, address);
} else {
- if (fault & VM_FAULT_SIGBUS)
- do_sigbus(regs, error_code, address);
+ if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON))
+ do_sigbus(regs, error_code, address, fault);
else
BUG();
}
.invalidatepage = btrfs_invalidatepage,
.releasepage = btrfs_releasepage,
.set_page_dirty = btrfs_set_page_dirty,
+ .error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations btrfs_symlink_aops = {
.writepages = ext2_writepages,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
const struct address_space_operations ext2_aops_xip = {
.direct_IO = ext2_direct_IO,
.writepages = ext2_writepages,
.migratepage = buffer_migrate_page,
+ .error_remove_page = generic_error_remove_page,
};
/*
.direct_IO = ext3_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations ext3_writeback_aops = {
.direct_IO = ext3_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations ext3_journalled_aops = {
.invalidatepage = ext3_invalidatepage,
.releasepage = ext3_releasepage,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
void ext3_set_aops(struct inode *inode)
.direct_IO = ext4_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations ext4_writeback_aops = {
.direct_IO = ext4_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations ext4_journalled_aops = {
.invalidatepage = ext4_invalidatepage,
.releasepage = ext4_releasepage,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations ext4_da_aops = {
.direct_IO = ext4_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
void ext4_set_aops(struct inode *inode)
.direct_IO = gfs2_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations gfs2_ordered_aops = {
.direct_IO = gfs2_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations gfs2_jdata_aops = {
.invalidatepage = gfs2_invalidatepage,
.releasepage = gfs2_releasepage,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
void gfs2_set_aops(struct inode *inode)
.direct_IO = nfs_direct_IO,
.migratepage = nfs_migrate_page,
.launder_page = nfs_launder_page,
+ .error_remove_page = generic_error_remove_page,
};
/*
.migratepage = buffer_migrate_page, /* Move a page cache page from
one physical page to an
other. */
+ .error_remove_page = generic_error_remove_page,
};
/**
.migratepage = buffer_migrate_page, /* Move a page cache page from
one physical page to an
other. */
+ .error_remove_page = generic_error_remove_page,
};
#ifdef NTFS_RW
.releasepage = ocfs2_releasepage,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
"Committed_AS: %8lu kB\n"
"VmallocTotal: %8lu kB\n"
"VmallocUsed: %8lu kB\n"
- "VmallocChunk: %8lu kB\n",
+ "VmallocChunk: %8lu kB\n"
+#ifdef CONFIG_MEMORY_FAILURE
+ "HardwareCorrupted: %8lu kB\n"
+#endif
+ ,
K(i.totalram),
K(i.freeram),
K(i.bufferram),
(unsigned long)VMALLOC_TOTAL >> 10,
vmi.used >> 10,
vmi.largest_chunk >> 10
+#ifdef CONFIG_MEMORY_FAILURE
+ ,atomic_long_read(&mce_bad_pages) << (PAGE_SHIFT - 10)
+#endif
);
hugetlb_report_meminfo(m);
.direct_IO = xfs_vm_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};
#define MADV_REMOVE 9 /* remove these pages & resources */
#define MADV_DONTFORK 10 /* don't inherit across fork */
#define MADV_DOFORK 11 /* do inherit across fork */
+#define MADV_HWPOISON 100 /* poison a page for testing */
#define MADV_MERGEABLE 12 /* KSM may merge identical pages */
#define MADV_UNMERGEABLE 13 /* KSM may not merge identical pages */
#ifdef __ARCH_SI_TRAPNO
int _trapno; /* TRAP # which caused the signal */
#endif
+ short _addr_lsb; /* LSB of the reported address */
} _sigfault;
/* SIGPOLL */
#ifdef __ARCH_SI_TRAPNO
#define si_trapno _sifields._sigfault._trapno
#endif
+#define si_addr_lsb _sifields._sigfault._addr_lsb
#define si_band _sifields._sigpoll._band
#define si_fd _sifields._sigpoll._fd
#define BUS_ADRALN (__SI_FAULT|1) /* invalid address alignment */
#define BUS_ADRERR (__SI_FAULT|2) /* non-existant physical address */
#define BUS_OBJERR (__SI_FAULT|3) /* object specific hardware error */
-#define NSIGBUS 3
+/* hardware memory error consumed on a machine check: action required */
+#define BUS_MCEERR_AR (__SI_FAULT|4)
+/* hardware memory error detected in process but not consumed: action optional*/
+#define BUS_MCEERR_AO (__SI_FAULT|5)
+#define NSIGBUS 5
/*
* SIGTRAP si_codes
int (*launder_page) (struct page *);
int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
unsigned long);
+ int (*error_remove_page)(struct address_space *, struct page *);
};
/*
#define VM_FAULT_SIGBUS 0x0002
#define VM_FAULT_MAJOR 0x0004
#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */
+#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned page */
#define VM_FAULT_NOPAGE 0x0100 /* ->fault installed the pte, not return page */
#define VM_FAULT_LOCKED 0x0200 /* ->fault locked the returned page */
-#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS)
+#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_HWPOISON)
/*
* Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
extern int vmtruncate(struct inode * inode, loff_t offset);
extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
+int truncate_inode_page(struct address_space *mapping, struct page *page);
+int generic_error_remove_page(struct address_space *mapping, struct page *page);
+
+int invalidate_inode_page(struct page *page);
+
#ifdef CONFIG_MMU
extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, unsigned int flags);
extern int account_locked_memory(struct mm_struct *mm, struct rlimit *rlim,
size_t size);
extern void refund_locked_memory(struct mm_struct *mm, size_t size);
+
+extern void memory_failure(unsigned long pfn, int trapno);
+extern int __memory_failure(unsigned long pfn, int trapno, int ref);
+extern int sysctl_memory_failure_early_kill;
+extern int sysctl_memory_failure_recovery;
+extern atomic_long_t mce_bad_pages;
+
#endif /* __KERNEL__ */
#endif /* _LINUX_MM_H */
* PG_buddy is set to indicate that the page is free and in the buddy system
* (see mm/page_alloc.c).
*
+ * PG_hwpoison indicates that a page got corrupted in hardware and contains
+ * data with incorrect ECC bits that triggered a machine check. Accessing is
+ * not safe since it may cause another machine check. Don't touch!
*/
/*
#ifdef CONFIG_ARCH_USES_PG_UNCACHED
PG_uncached, /* Page has been mapped as uncached */
#endif
+#ifdef CONFIG_MEMORY_FAILURE
+ PG_hwpoison, /* hardware poisoned page. Don't touch */
+#endif
__NR_PAGEFLAGS,
/* Filesystems */
PAGEFLAG_FALSE(Uncached)
#endif
+#ifdef CONFIG_MEMORY_FAILURE
+PAGEFLAG(HWPoison, hwpoison)
+TESTSETFLAG(HWPoison, hwpoison)
+#define __PG_HWPOISON (1UL << PG_hwpoison)
+#else
+PAGEFLAG_FALSE(HWPoison)
+#define __PG_HWPOISON 0
+#endif
+
static inline int PageUptodate(struct page *page)
{
int ret = test_bit(PG_uptodate, &(page)->flags);
1 << PG_private | 1 << PG_private_2 | \
1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
- 1 << PG_unevictable | __PG_MLOCKED)
+ 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON)
/*
* Flags checked when a page is prepped for return by the page allocator.
#define PR_TASK_PERF_EVENTS_DISABLE 31
#define PR_TASK_PERF_EVENTS_ENABLE 32
+#define PR_MCE_KILL 33
+
#endif /* _LINUX_PRCTL_H */
*/
int page_referenced(struct page *, int is_locked,
struct mem_cgroup *cnt, unsigned long *vm_flags);
-int try_to_unmap(struct page *, int ignore_refs);
+enum ttu_flags {
+ TTU_UNMAP = 0, /* unmap mode */
+ TTU_MIGRATION = 1, /* migration mode */
+ TTU_MUNLOCK = 2, /* munlock mode */
+ TTU_ACTION_MASK = 0xff,
+
+ TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
+ TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
+ TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
+};
+#define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
+
+int try_to_unmap(struct page *, enum ttu_flags flags);
/*
* Called from mm/filemap_xip.c to unmap empty zero page
*/
int try_to_munlock(struct page *);
+/*
+ * Called by memory-failure.c to kill processes.
+ */
+struct anon_vma *page_lock_anon_vma(struct page *page);
+void page_unlock_anon_vma(struct anon_vma *anon_vma);
+int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
+
#else /* !CONFIG_MMU */
#define anon_vma_init() do {} while (0)
#define PF_EXITPIDONE 0x00000008 /* pi exit done on shut down */
#define PF_VCPU 0x00000010 /* I'm a virtual CPU */
#define PF_FORKNOEXEC 0x00000040 /* forked but didn't exec */
+#define PF_MCE_PROCESS 0x00000080 /* process policy on mce errors */
#define PF_SUPERPRIV 0x00000100 /* used super-user privileges */
#define PF_DUMPCORE 0x00000200 /* dumped core */
#define PF_SIGNALED 0x00000400 /* killed by a signal */
#define PF_SPREAD_PAGE 0x01000000 /* Spread page cache over cpuset */
#define PF_SPREAD_SLAB 0x02000000 /* Spread some slab caches over cpuset */
#define PF_THREAD_BOUND 0x04000000 /* Thread bound to specific cpu */
+#define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */
#define PF_MEMPOLICY 0x10000000 /* Non-default NUMA mempolicy */
#define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */
#define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezeable */
* the type/offset into the pte as 5/27 as well.
*/
#define MAX_SWAPFILES_SHIFT 5
-#ifndef CONFIG_MIGRATION
-#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
+
+/*
+ * Use some of the swap files numbers for other purposes. This
+ * is a convenient way to hook into the VM to trigger special
+ * actions on faults.
+ */
+
+/*
+ * NUMA node memory migration support
+ */
+#ifdef CONFIG_MIGRATION
+#define SWP_MIGRATION_NUM 2
+#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM)
+#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
#else
-/* Use last two entries for page migration swap entries */
-#define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2)
-#define SWP_MIGRATION_READ MAX_SWAPFILES
-#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1)
+#define SWP_MIGRATION_NUM 0
#endif
/*
+ * Handling of hardware poisoned pages with memory corruption.
+ */
+#ifdef CONFIG_MEMORY_FAILURE
+#define SWP_HWPOISON_NUM 1
+#define SWP_HWPOISON MAX_SWAPFILES
+#else
+#define SWP_HWPOISON_NUM 0
+#endif
+
+#define MAX_SWAPFILES \
+ ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
+
+/*
* Magic header for a swap area. The first part of the union is
* what the swap magic looks like for the old (limited to 128MB)
* swap area format, the second part of the union adds - in the
#endif
+#ifdef CONFIG_MEMORY_FAILURE
+/*
+ * Support for hardware poisoned pages
+ */
+static inline swp_entry_t make_hwpoison_entry(struct page *page)
+{
+ BUG_ON(!PageLocked(page));
+ return swp_entry(SWP_HWPOISON, page_to_pfn(page));
+}
+
+static inline int is_hwpoison_entry(swp_entry_t entry)
+{
+ return swp_type(entry) == SWP_HWPOISON;
+}
+#else
+
+static inline swp_entry_t make_hwpoison_entry(struct page *page)
+{
+ return swp_entry(0, 0);
+}
+
+static inline int is_hwpoison_entry(swp_entry_t swp)
+{
+ return 0;
+}
+#endif
+
+#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION)
+static inline int non_swap_entry(swp_entry_t entry)
+{
+ return swp_type(entry) >= MAX_SWAPFILES;
+}
+#else
+static inline int non_swap_entry(swp_entry_t entry)
+{
+ return 0;
+}
+#endif
current->timer_slack_ns = arg2;
error = 0;
break;
+ case PR_MCE_KILL:
+ if (arg4 | arg5)
+ return -EINVAL;
+ switch (arg2) {
+ case 0:
+ if (arg3 != 0)
+ return -EINVAL;
+ current->flags &= ~PF_MCE_PROCESS;
+ break;
+ case 1:
+ current->flags |= PF_MCE_PROCESS;
+ if (arg3 != 0)
+ current->flags |= PF_MCE_EARLY;
+ else
+ current->flags &= ~PF_MCE_EARLY;
+ break;
+ default:
+ return -EINVAL;
+ }
+ error = 0;
+ break;
+
default:
error = -EINVAL;
break;
.mode = 0644,
.proc_handler = &scan_unevictable_handler,
},
+#ifdef CONFIG_MEMORY_FAILURE
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "memory_failure_early_kill",
+ .data = &sysctl_memory_failure_early_kill,
+ .maxlen = sizeof(sysctl_memory_failure_early_kill),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .strategy = &sysctl_intvec,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ {
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "memory_failure_recovery",
+ .data = &sysctl_memory_failure_recovery,
+ .maxlen = sizeof(sysctl_memory_failure_recovery),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec_minmax,
+ .strategy = &sysctl_intvec,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+#endif
+
/*
* NOTE: do not add new entries to this table unless you have read
* Documentation/sysctl/ctl_unnumbered.txt
/proc/sys/vm/mmap_min_addr tunable.
+config MEMORY_FAILURE
+ depends on MMU
+ depends on X86_MCE
+ bool "Enable recovery from hardware memory errors"
+ help
+ Enables code to recover from some memory failures on systems
+ with MCA recovery. This allows a system to continue running
+ even when some of its memory has uncorrected errors. This requires
+ special hardware support and typically ECC memory.
+
+config HWPOISON_INJECT
+ tristate "Poison pages injector"
+ depends on MEMORY_FAILURE && DEBUG_KERNEL
+
config NOMMU_INITIAL_TRIM_EXCESS
int "Turn on mmap() excess space trimming before booting"
depends on !MMU
endif
obj-$(CONFIG_QUICKLIST) += quicklist.o
obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o
+obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o
+obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o
*
* ->task->proc_lock
* ->dcache_lock (proc_pid_lookup)
+ *
+ * (code doesn't rely on that order, so you could switch it around)
+ * ->tasklist_lock (memory_failure, collect_procs_ao)
+ * ->i_mmap_lock
*/
/*
--- /dev/null
+/* Inject a hwpoison memory failure on a arbitary pfn */
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+
+static struct dentry *hwpoison_dir, *corrupt_pfn;
+
+static int hwpoison_inject(void *data, u64 val)
+{
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ printk(KERN_INFO "Injecting memory failure at pfn %Lx\n", val);
+ return __memory_failure(val, 18, 0);
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
+
+static void pfn_inject_exit(void)
+{
+ if (hwpoison_dir)
+ debugfs_remove_recursive(hwpoison_dir);
+}
+
+static int pfn_inject_init(void)
+{
+ hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
+ if (hwpoison_dir == NULL)
+ return -ENOMEM;
+ corrupt_pfn = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir,
+ NULL, &hwpoison_fops);
+ if (corrupt_pfn == NULL) {
+ pfn_inject_exit();
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+module_init(pfn_inject_init);
+module_exit(pfn_inject_exit);
+MODULE_LICENSE("GPL");
return error;
}
+#ifdef CONFIG_MEMORY_FAILURE
+/*
+ * Error injection support for memory error handling.
+ */
+static int madvise_hwpoison(unsigned long start, unsigned long end)
+{
+ int ret = 0;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ for (; start < end; start += PAGE_SIZE) {
+ struct page *p;
+ int ret = get_user_pages(current, current->mm, start, 1,
+ 0, 0, &p, NULL);
+ if (ret != 1)
+ return ret;
+ printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
+ page_to_pfn(p), start);
+ /* Ignore return value for now */
+ __memory_failure(page_to_pfn(p), 0, 1);
+ put_page(p);
+ }
+ return ret;
+}
+#endif
+
static long
madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
unsigned long start, unsigned long end, int behavior)
int write;
size_t len;
+#ifdef CONFIG_MEMORY_FAILURE
+ if (behavior == MADV_HWPOISON)
+ return madvise_hwpoison(start, start+len_in);
+#endif
if (!madvise_behavior_valid(behavior))
return error;
--- /dev/null
+/*
+ * Copyright (C) 2008, 2009 Intel Corporation
+ * Authors: Andi Kleen, Fengguang Wu
+ *
+ * This software may be redistributed and/or modified under the terms of
+ * the GNU General Public License ("GPL") version 2 only as published by the
+ * Free Software Foundation.
+ *
+ * High level machine check handler. Handles pages reported by the
+ * hardware as being corrupted usually due to a 2bit ECC memory or cache
+ * failure.
+ *
+ * Handles page cache pages in various states. The tricky part
+ * here is that we can access any page asynchronous to other VM
+ * users, because memory failures could happen anytime and anywhere,
+ * possibly violating some of their assumptions. This is why this code
+ * has to be extremely careful. Generally it tries to use normal locking
+ * rules, as in get the standard locks, even if that means the
+ * error handling takes potentially a long time.
+ *
+ * The operation to map back from RMAP chains to processes has to walk
+ * the complete process list and has non linear complexity with the number
+ * mappings. In short it can be quite slow. But since memory corruptions
+ * are rare we hope to get away with this.
+ */
+
+/*
+ * Notebook:
+ * - hugetlb needs more code
+ * - kcore/oldmem/vmcore/mem/kmem check for hwpoison pages
+ * - pass bad pages to kdump next kernel
+ */
+#define DEBUG 1 /* remove me in 2.6.34 */
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/page-flags.h>
+#include <linux/sched.h>
+#include <linux/rmap.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <linux/backing-dev.h>
+#include "internal.h"
+
+int sysctl_memory_failure_early_kill __read_mostly = 0;
+
+int sysctl_memory_failure_recovery __read_mostly = 1;
+
+atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);
+
+/*
+ * Send all the processes who have the page mapped an ``action optional''
+ * signal.
+ */
+static int kill_proc_ao(struct task_struct *t, unsigned long addr, int trapno,
+ unsigned long pfn)
+{
+ struct siginfo si;
+ int ret;
+
+ printk(KERN_ERR
+ "MCE %#lx: Killing %s:%d early due to hardware memory corruption\n",
+ pfn, t->comm, t->pid);
+ si.si_signo = SIGBUS;
+ si.si_errno = 0;
+ si.si_code = BUS_MCEERR_AO;
+ si.si_addr = (void *)addr;
+#ifdef __ARCH_SI_TRAPNO
+ si.si_trapno = trapno;
+#endif
+ si.si_addr_lsb = PAGE_SHIFT;
+ /*
+ * Don't use force here, it's convenient if the signal
+ * can be temporarily blocked.
+ * This could cause a loop when the user sets SIGBUS
+ * to SIG_IGN, but hopefully noone will do that?
+ */
+ ret = send_sig_info(SIGBUS, &si, t); /* synchronous? */
+ if (ret < 0)
+ printk(KERN_INFO "MCE: Error sending signal to %s:%d: %d\n",
+ t->comm, t->pid, ret);
+ return ret;
+}
+
+/*
+ * Kill all processes that have a poisoned page mapped and then isolate
+ * the page.
+ *
+ * General strategy:
+ * Find all processes having the page mapped and kill them.
+ * But we keep a page reference around so that the page is not
+ * actually freed yet.
+ * Then stash the page away
+ *
+ * There's no convenient way to get back to mapped processes
+ * from the VMAs. So do a brute-force search over all
+ * running processes.
+ *
+ * Remember that machine checks are not common (or rather
+ * if they are common you have other problems), so this shouldn't
+ * be a performance issue.
+ *
+ * Also there are some races possible while we get from the
+ * error detection to actually handle it.
+ */
+
+struct to_kill {
+ struct list_head nd;
+ struct task_struct *tsk;
+ unsigned long addr;
+ unsigned addr_valid:1;
+};
+
+/*
+ * Failure handling: if we can't find or can't kill a process there's
+ * not much we can do. We just print a message and ignore otherwise.
+ */
+
+/*
+ * Schedule a process for later kill.
+ * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
+ * TBD would GFP_NOIO be enough?
+ */
+static void add_to_kill(struct task_struct *tsk, struct page *p,
+ struct vm_area_struct *vma,
+ struct list_head *to_kill,
+ struct to_kill **tkc)
+{
+ struct to_kill *tk;
+
+ if (*tkc) {
+ tk = *tkc;
+ *tkc = NULL;
+ } else {
+ tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC);
+ if (!tk) {
+ printk(KERN_ERR
+ "MCE: Out of memory while machine check handling\n");
+ return;
+ }
+ }
+ tk->addr = page_address_in_vma(p, vma);
+ tk->addr_valid = 1;
+
+ /*
+ * In theory we don't have to kill when the page was
+ * munmaped. But it could be also a mremap. Since that's
+ * likely very rare kill anyways just out of paranoia, but use
+ * a SIGKILL because the error is not contained anymore.
+ */
+ if (tk->addr == -EFAULT) {
+ pr_debug("MCE: Unable to find user space address %lx in %s\n",
+ page_to_pfn(p), tsk->comm);
+ tk->addr_valid = 0;
+ }
+ get_task_struct(tsk);
+ tk->tsk = tsk;
+ list_add_tail(&tk->nd, to_kill);
+}
+
+/*
+ * Kill the processes that have been collected earlier.
+ *
+ * Only do anything when DOIT is set, otherwise just free the list
+ * (this is used for clean pages which do not need killing)
+ * Also when FAIL is set do a force kill because something went
+ * wrong earlier.
+ */
+static void kill_procs_ao(struct list_head *to_kill, int doit, int trapno,
+ int fail, unsigned long pfn)
+{
+ struct to_kill *tk, *next;
+
+ list_for_each_entry_safe (tk, next, to_kill, nd) {
+ if (doit) {
+ /*
+ * In case something went wrong with munmaping
+ * make sure the process doesn't catch the
+ * signal and then access the memory. Just kill it.
+ * the signal handlers
+ */
+ if (fail || tk->addr_valid == 0) {
+ printk(KERN_ERR
+ "MCE %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n",
+ pfn, tk->tsk->comm, tk->tsk->pid);
+ force_sig(SIGKILL, tk->tsk);
+ }
+
+ /*
+ * In theory the process could have mapped
+ * something else on the address in-between. We could
+ * check for that, but we need to tell the
+ * process anyways.
+ */
+ else if (kill_proc_ao(tk->tsk, tk->addr, trapno,
+ pfn) < 0)
+ printk(KERN_ERR
+ "MCE %#lx: Cannot send advisory machine check signal to %s:%d\n",
+ pfn, tk->tsk->comm, tk->tsk->pid);
+ }
+ put_task_struct(tk->tsk);
+ kfree(tk);
+ }
+}
+
+static int task_early_kill(struct task_struct *tsk)
+{
+ if (!tsk->mm)
+ return 0;
+ if (tsk->flags & PF_MCE_PROCESS)
+ return !!(tsk->flags & PF_MCE_EARLY);
+ return sysctl_memory_failure_early_kill;
+}
+
+/*
+ * Collect processes when the error hit an anonymous page.
+ */
+static void collect_procs_anon(struct page *page, struct list_head *to_kill,
+ struct to_kill **tkc)
+{
+ struct vm_area_struct *vma;
+ struct task_struct *tsk;
+ struct anon_vma *av;
+
+ read_lock(&tasklist_lock);
+ av = page_lock_anon_vma(page);
+ if (av == NULL) /* Not actually mapped anymore */
+ goto out;
+ for_each_process (tsk) {
+ if (!task_early_kill(tsk))
+ continue;
+ list_for_each_entry (vma, &av->head, anon_vma_node) {
+ if (!page_mapped_in_vma(page, vma))
+ continue;
+ if (vma->vm_mm == tsk->mm)
+ add_to_kill(tsk, page, vma, to_kill, tkc);
+ }
+ }
+ page_unlock_anon_vma(av);
+out:
+ read_unlock(&tasklist_lock);
+}
+
+/*
+ * Collect processes when the error hit a file mapped page.
+ */
+static void collect_procs_file(struct page *page, struct list_head *to_kill,
+ struct to_kill **tkc)
+{
+ struct vm_area_struct *vma;
+ struct task_struct *tsk;
+ struct prio_tree_iter iter;
+ struct address_space *mapping = page->mapping;
+
+ /*
+ * A note on the locking order between the two locks.
+ * We don't rely on this particular order.
+ * If you have some other code that needs a different order
+ * feel free to switch them around. Or add a reverse link
+ * from mm_struct to task_struct, then this could be all
+ * done without taking tasklist_lock and looping over all tasks.
+ */
+
+ read_lock(&tasklist_lock);
+ spin_lock(&mapping->i_mmap_lock);
+ for_each_process(tsk) {
+ pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
+
+ if (!task_early_kill(tsk))
+ continue;
+
+ vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff,
+ pgoff) {
+ /*
+ * Send early kill signal to tasks where a vma covers
+ * the page but the corrupted page is not necessarily
+ * mapped it in its pte.
+ * Assume applications who requested early kill want
+ * to be informed of all such data corruptions.
+ */
+ if (vma->vm_mm == tsk->mm)
+ add_to_kill(tsk, page, vma, to_kill, tkc);
+ }
+ }
+ spin_unlock(&mapping->i_mmap_lock);
+ read_unlock(&tasklist_lock);
+}
+
+/*
+ * Collect the processes who have the corrupted page mapped to kill.
+ * This is done in two steps for locking reasons.
+ * First preallocate one tokill structure outside the spin locks,
+ * so that we can kill at least one process reasonably reliable.
+ */
+static void collect_procs(struct page *page, struct list_head *tokill)
+{
+ struct to_kill *tk;
+
+ if (!page->mapping)
+ return;
+
+ tk = kmalloc(sizeof(struct to_kill), GFP_NOIO);
+ if (!tk)
+ return;
+ if (PageAnon(page))
+ collect_procs_anon(page, tokill, &tk);
+ else
+ collect_procs_file(page, tokill, &tk);
+ kfree(tk);
+}
+
+/*
+ * Error handlers for various types of pages.
+ */
+
+enum outcome {
+ FAILED, /* Error handling failed */
+ DELAYED, /* Will be handled later */
+ IGNORED, /* Error safely ignored */
+ RECOVERED, /* Successfully recovered */
+};
+
+static const char *action_name[] = {
+ [FAILED] = "Failed",
+ [DELAYED] = "Delayed",
+ [IGNORED] = "Ignored",
+ [RECOVERED] = "Recovered",
+};
+
+/*
+ * Error hit kernel page.
+ * Do nothing, try to be lucky and not touch this instead. For a few cases we
+ * could be more sophisticated.
+ */
+static int me_kernel(struct page *p, unsigned long pfn)
+{
+ return DELAYED;
+}
+
+/*
+ * Already poisoned page.
+ */
+static int me_ignore(struct page *p, unsigned long pfn)
+{
+ return IGNORED;
+}
+
+/*
+ * Page in unknown state. Do nothing.
+ */
+static int me_unknown(struct page *p, unsigned long pfn)
+{
+ printk(KERN_ERR "MCE %#lx: Unknown page state\n", pfn);
+ return FAILED;
+}
+
+/*
+ * Free memory
+ */
+static int me_free(struct page *p, unsigned long pfn)
+{
+ return DELAYED;
+}
+
+/*
+ * Clean (or cleaned) page cache page.
+ */
+static int me_pagecache_clean(struct page *p, unsigned long pfn)
+{
+ int err;
+ int ret = FAILED;
+ struct address_space *mapping;
+
+ if (!isolate_lru_page(p))
+ page_cache_release(p);
+
+ /*
+ * For anonymous pages we're done the only reference left
+ * should be the one m_f() holds.
+ */
+ if (PageAnon(p))
+ return RECOVERED;
+
+ /*
+ * Now truncate the page in the page cache. This is really
+ * more like a "temporary hole punch"
+ * Don't do this for block devices when someone else
+ * has a reference, because it could be file system metadata
+ * and that's not safe to truncate.
+ */
+ mapping = page_mapping(p);
+ if (!mapping) {
+ /*
+ * Page has been teared down in the meanwhile
+ */
+ return FAILED;
+ }
+
+ /*
+ * Truncation is a bit tricky. Enable it per file system for now.
+ *
+ * Open: to take i_mutex or not for this? Right now we don't.
+ */
+ if (mapping->a_ops->error_remove_page) {
+ err = mapping->a_ops->error_remove_page(mapping, p);
+ if (err != 0) {
+ printk(KERN_INFO "MCE %#lx: Failed to punch page: %d\n",
+ pfn, err);
+ } else if (page_has_private(p) &&
+ !try_to_release_page(p, GFP_NOIO)) {
+ pr_debug("MCE %#lx: failed to release buffers\n", pfn);
+ } else {
+ ret = RECOVERED;
+ }
+ } else {
+ /*
+ * If the file system doesn't support it just invalidate
+ * This fails on dirty or anything with private pages
+ */
+ if (invalidate_inode_page(p))
+ ret = RECOVERED;
+ else
+ printk(KERN_INFO "MCE %#lx: Failed to invalidate\n",
+ pfn);
+ }
+ return ret;
+}
+
+/*
+ * Dirty cache page page
+ * Issues: when the error hit a hole page the error is not properly
+ * propagated.
+ */
+static int me_pagecache_dirty(struct page *p, unsigned long pfn)
+{
+ struct address_space *mapping = page_mapping(p);
+
+ SetPageError(p);
+ /* TBD: print more information about the file. */
+ if (mapping) {
+ /*
+ * IO error will be reported by write(), fsync(), etc.
+ * who check the mapping.
+ * This way the application knows that something went
+ * wrong with its dirty file data.
+ *
+ * There's one open issue:
+ *
+ * The EIO will be only reported on the next IO
+ * operation and then cleared through the IO map.
+ * Normally Linux has two mechanisms to pass IO error
+ * first through the AS_EIO flag in the address space
+ * and then through the PageError flag in the page.
+ * Since we drop pages on memory failure handling the
+ * only mechanism open to use is through AS_AIO.
+ *
+ * This has the disadvantage that it gets cleared on
+ * the first operation that returns an error, while
+ * the PageError bit is more sticky and only cleared
+ * when the page is reread or dropped. If an
+ * application assumes it will always get error on
+ * fsync, but does other operations on the fd before
+ * and the page is dropped inbetween then the error
+ * will not be properly reported.
+ *
+ * This can already happen even without hwpoisoned
+ * pages: first on metadata IO errors (which only
+ * report through AS_EIO) or when the page is dropped
+ * at the wrong time.
+ *
+ * So right now we assume that the application DTRT on
+ * the first EIO, but we're not worse than other parts
+ * of the kernel.
+ */
+ mapping_set_error(mapping, EIO);
+ }
+
+ return me_pagecache_clean(p, pfn);
+}
+
+/*
+ * Clean and dirty swap cache.
+ *
+ * Dirty swap cache page is tricky to handle. The page could live both in page
+ * cache and swap cache(ie. page is freshly swapped in). So it could be
+ * referenced concurrently by 2 types of PTEs:
+ * normal PTEs and swap PTEs. We try to handle them consistently by calling
+ * try_to_unmap(TTU_IGNORE_HWPOISON) to convert the normal PTEs to swap PTEs,
+ * and then
+ * - clear dirty bit to prevent IO
+ * - remove from LRU
+ * - but keep in the swap cache, so that when we return to it on
+ * a later page fault, we know the application is accessing
+ * corrupted data and shall be killed (we installed simple
+ * interception code in do_swap_page to catch it).
+ *
+ * Clean swap cache pages can be directly isolated. A later page fault will
+ * bring in the known good data from disk.
+ */
+static int me_swapcache_dirty(struct page *p, unsigned long pfn)
+{
+ int ret = FAILED;
+
+ ClearPageDirty(p);
+ /* Trigger EIO in shmem: */
+ ClearPageUptodate(p);
+
+ if (!isolate_lru_page(p)) {
+ page_cache_release(p);
+ ret = DELAYED;
+ }
+
+ return ret;
+}
+
+static int me_swapcache_clean(struct page *p, unsigned long pfn)
+{
+ int ret = FAILED;
+
+ if (!isolate_lru_page(p)) {
+ page_cache_release(p);
+ ret = RECOVERED;
+ }
+ delete_from_swap_cache(p);
+ return ret;
+}
+
+/*
+ * Huge pages. Needs work.
+ * Issues:
+ * No rmap support so we cannot find the original mapper. In theory could walk
+ * all MMs and look for the mappings, but that would be non atomic and racy.
+ * Need rmap for hugepages for this. Alternatively we could employ a heuristic,
+ * like just walking the current process and hoping it has it mapped (that
+ * should be usually true for the common "shared database cache" case)
+ * Should handle free huge pages and dequeue them too, but this needs to
+ * handle huge page accounting correctly.
+ */
+static int me_huge_page(struct page *p, unsigned long pfn)
+{
+ return FAILED;
+}
+
+/*
+ * Various page states we can handle.
+ *
+ * A page state is defined by its current page->flags bits.
+ * The table matches them in order and calls the right handler.
+ *
+ * This is quite tricky because we can access page at any time
+ * in its live cycle, so all accesses have to be extremly careful.
+ *
+ * This is not complete. More states could be added.
+ * For any missing state don't attempt recovery.
+ */
+
+#define dirty (1UL << PG_dirty)
+#define sc (1UL << PG_swapcache)
+#define unevict (1UL << PG_unevictable)
+#define mlock (1UL << PG_mlocked)
+#define writeback (1UL << PG_writeback)
+#define lru (1UL << PG_lru)
+#define swapbacked (1UL << PG_swapbacked)
+#define head (1UL << PG_head)
+#define tail (1UL << PG_tail)
+#define compound (1UL << PG_compound)
+#define slab (1UL << PG_slab)
+#define buddy (1UL << PG_buddy)
+#define reserved (1UL << PG_reserved)
+
+static struct page_state {
+ unsigned long mask;
+ unsigned long res;
+ char *msg;
+ int (*action)(struct page *p, unsigned long pfn);
+} error_states[] = {
+ { reserved, reserved, "reserved kernel", me_ignore },
+ { buddy, buddy, "free kernel", me_free },
+
+ /*
+ * Could in theory check if slab page is free or if we can drop
+ * currently unused objects without touching them. But just
+ * treat it as standard kernel for now.
+ */
+ { slab, slab, "kernel slab", me_kernel },
+
+#ifdef CONFIG_PAGEFLAGS_EXTENDED
+ { head, head, "huge", me_huge_page },
+ { tail, tail, "huge", me_huge_page },
+#else
+ { compound, compound, "huge", me_huge_page },
+#endif
+
+ { sc|dirty, sc|dirty, "swapcache", me_swapcache_dirty },
+ { sc|dirty, sc, "swapcache", me_swapcache_clean },
+
+ { unevict|dirty, unevict|dirty, "unevictable LRU", me_pagecache_dirty},
+ { unevict, unevict, "unevictable LRU", me_pagecache_clean},
+
+#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
+ { mlock|dirty, mlock|dirty, "mlocked LRU", me_pagecache_dirty },
+ { mlock, mlock, "mlocked LRU", me_pagecache_clean },
+#endif
+
+ { lru|dirty, lru|dirty, "LRU", me_pagecache_dirty },
+ { lru|dirty, lru, "clean LRU", me_pagecache_clean },
+ { swapbacked, swapbacked, "anonymous", me_pagecache_clean },
+
+ /*
+ * Catchall entry: must be at end.
+ */
+ { 0, 0, "unknown page state", me_unknown },
+};
+
+#undef lru
+
+static void action_result(unsigned long pfn, char *msg, int result)
+{
+ struct page *page = NULL;
+ if (pfn_valid(pfn))
+ page = pfn_to_page(pfn);
+
+ printk(KERN_ERR "MCE %#lx: %s%s page recovery: %s\n",
+ pfn,
+ page && PageDirty(page) ? "dirty " : "",
+ msg, action_name[result]);
+}
+
+static int page_action(struct page_state *ps, struct page *p,
+ unsigned long pfn, int ref)
+{
+ int result;
+
+ result = ps->action(p, pfn);
+ action_result(pfn, ps->msg, result);
+ if (page_count(p) != 1 + ref)
+ printk(KERN_ERR
+ "MCE %#lx: %s page still referenced by %d users\n",
+ pfn, ps->msg, page_count(p) - 1);
+
+ /* Could do more checks here if page looks ok */
+ /*
+ * Could adjust zone counters here to correct for the missing page.
+ */
+
+ return result == RECOVERED ? 0 : -EBUSY;
+}
+
+#define N_UNMAP_TRIES 5
+
+/*
+ * Do all that is necessary to remove user space mappings. Unmap
+ * the pages and send SIGBUS to the processes if the data was dirty.
+ */
+static void hwpoison_user_mappings(struct page *p, unsigned long pfn,
+ int trapno)
+{
+ enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
+ struct address_space *mapping;
+ LIST_HEAD(tokill);
+ int ret;
+ int i;
+ int kill = 1;
+
+ if (PageReserved(p) || PageCompound(p) || PageSlab(p))
+ return;
+
+ if (!PageLRU(p))
+ lru_add_drain_all();
+
+ /*
+ * This check implies we don't kill processes if their pages
+ * are in the swap cache early. Those are always late kills.
+ */
+ if (!page_mapped(p))
+ return;
+
+ if (PageSwapCache(p)) {
+ printk(KERN_ERR
+ "MCE %#lx: keeping poisoned page in swap cache\n", pfn);
+ ttu |= TTU_IGNORE_HWPOISON;
+ }
+
+ /*
+ * Propagate the dirty bit from PTEs to struct page first, because we
+ * need this to decide if we should kill or just drop the page.
+ */
+ mapping = page_mapping(p);
+ if (!PageDirty(p) && mapping && mapping_cap_writeback_dirty(mapping)) {
+ if (page_mkclean(p)) {
+ SetPageDirty(p);
+ } else {
+ kill = 0;
+ ttu |= TTU_IGNORE_HWPOISON;
+ printk(KERN_INFO
+ "MCE %#lx: corrupted page was clean: dropped without side effects\n",
+ pfn);
+ }
+ }
+
+ /*
+ * First collect all the processes that have the page
+ * mapped in dirty form. This has to be done before try_to_unmap,
+ * because ttu takes the rmap data structures down.
+ *
+ * Error handling: We ignore errors here because
+ * there's nothing that can be done.
+ */
+ if (kill)
+ collect_procs(p, &tokill);
+
+ /*
+ * try_to_unmap can fail temporarily due to races.
+ * Try a few times (RED-PEN better strategy?)
+ */
+ for (i = 0; i < N_UNMAP_TRIES; i++) {
+ ret = try_to_unmap(p, ttu);
+ if (ret == SWAP_SUCCESS)
+ break;
+ pr_debug("MCE %#lx: try_to_unmap retry needed %d\n", pfn, ret);
+ }
+
+ if (ret != SWAP_SUCCESS)
+ printk(KERN_ERR "MCE %#lx: failed to unmap page (mapcount=%d)\n",
+ pfn, page_mapcount(p));
+
+ /*
+ * Now that the dirty bit has been propagated to the
+ * struct page and all unmaps done we can decide if
+ * killing is needed or not. Only kill when the page
+ * was dirty, otherwise the tokill list is merely
+ * freed. When there was a problem unmapping earlier
+ * use a more force-full uncatchable kill to prevent
+ * any accesses to the poisoned memory.
+ */
+ kill_procs_ao(&tokill, !!PageDirty(p), trapno,
+ ret != SWAP_SUCCESS, pfn);
+}
+
+int __memory_failure(unsigned long pfn, int trapno, int ref)
+{
+ struct page_state *ps;
+ struct page *p;
+ int res;
+
+ if (!sysctl_memory_failure_recovery)
+ panic("Memory failure from trap %d on page %lx", trapno, pfn);
+
+ if (!pfn_valid(pfn)) {
+ action_result(pfn, "memory outside kernel control", IGNORED);
+ return -EIO;
+ }
+
+ p = pfn_to_page(pfn);
+ if (TestSetPageHWPoison(p)) {
+ action_result(pfn, "already hardware poisoned", IGNORED);
+ return 0;
+ }
+
+ atomic_long_add(1, &mce_bad_pages);
+
+ /*
+ * We need/can do nothing about count=0 pages.
+ * 1) it's a free page, and therefore in safe hand:
+ * prep_new_page() will be the gate keeper.
+ * 2) it's part of a non-compound high order page.
+ * Implies some kernel user: cannot stop them from
+ * R/W the page; let's pray that the page has been
+ * used and will be freed some time later.
+ * In fact it's dangerous to directly bump up page count from 0,
+ * that may make page_freeze_refs()/page_unfreeze_refs() mismatch.
+ */
+ if (!get_page_unless_zero(compound_head(p))) {
+ action_result(pfn, "free or high order kernel", IGNORED);
+ return PageBuddy(compound_head(p)) ? 0 : -EBUSY;
+ }
+
+ /*
+ * Lock the page and wait for writeback to finish.
+ * It's very difficult to mess with pages currently under IO
+ * and in many cases impossible, so we just avoid it here.
+ */
+ lock_page_nosync(p);
+ wait_on_page_writeback(p);
+
+ /*
+ * Now take care of user space mappings.
+ */
+ hwpoison_user_mappings(p, pfn, trapno);
+
+ /*
+ * Torn down by someone else?
+ */
+ if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) {
+ action_result(pfn, "already truncated LRU", IGNORED);
+ res = 0;
+ goto out;
+ }
+
+ res = -EBUSY;
+ for (ps = error_states;; ps++) {
+ if ((p->flags & ps->mask) == ps->res) {
+ res = page_action(ps, p, pfn, ref);
+ break;
+ }
+ }
+out:
+ unlock_page(p);
+ return res;
+}
+EXPORT_SYMBOL_GPL(__memory_failure);
+
+/**
+ * memory_failure - Handle memory failure of a page.
+ * @pfn: Page Number of the corrupted page
+ * @trapno: Trap number reported in the signal to user space.
+ *
+ * This function is called by the low level machine check code
+ * of an architecture when it detects hardware memory corruption
+ * of a page. It tries its best to recover, which includes
+ * dropping pages, killing processes etc.
+ *
+ * The function is primarily of use for corruptions that
+ * happen outside the current execution context (e.g. when
+ * detected by a background scrubber)
+ *
+ * Must run in process context (e.g. a work queue) with interrupts
+ * enabled and no spinlocks hold.
+ */
+void memory_failure(unsigned long pfn, int trapno)
+{
+ __memory_failure(pfn, trapno, 0);
+}
if (ret & VM_FAULT_ERROR) {
if (ret & VM_FAULT_OOM)
return i ? i : -ENOMEM;
- else if (ret & VM_FAULT_SIGBUS)
+ if (ret &
+ (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
return i ? i : -EFAULT;
BUG();
}
goto out;
entry = pte_to_swp_entry(orig_pte);
- if (is_migration_entry(entry)) {
- migration_entry_wait(mm, pmd, address);
+ if (unlikely(non_swap_entry(entry))) {
+ if (is_migration_entry(entry)) {
+ migration_entry_wait(mm, pmd, address);
+ } else if (is_hwpoison_entry(entry)) {
+ ret = VM_FAULT_HWPOISON;
+ } else {
+ print_bad_pte(vma, address, orig_pte, NULL);
+ ret = VM_FAULT_OOM;
+ }
goto out;
}
delayacct_set_flag(DELAYACCT_PF_SWAPIN);
/* Had to read the page from swap area: Major fault */
ret = VM_FAULT_MAJOR;
count_vm_event(PGMAJFAULT);
+ } else if (PageHWPoison(page)) {
+ ret = VM_FAULT_HWPOISON;
+ delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
+ goto out;
}
lock_page(page);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
return ret;
+ if (unlikely(PageHWPoison(vmf.page))) {
+ if (ret & VM_FAULT_LOCKED)
+ unlock_page(vmf.page);
+ return VM_FAULT_HWPOISON;
+ }
+
/*
* For consistency in subsequent calls, make the faulted page always
* locked.
}
/* Establish migration ptes or remove ptes */
- try_to_unmap(page, 1);
+ try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
skip_unmap:
if (!page_mapped(page))
EXPORT_SYMBOL(redirty_page_for_writepage);
/*
+ * Dirty a page.
+ *
+ * For pages with a mapping this should be done under the page lock
+ * for the benefit of asynchronous memory errors who prefer a consistent
+ * dirty state. This rule can be broken in some special cases,
+ * but should be better not to.
+ *
* If the mapping doesn't provide a set_page_dirty a_op, then
* just fall through and assume that it wants buffer_heads.
*/
static unsigned long nr_shown;
static unsigned long nr_unshown;
+ /* Don't complain about poisoned pages */
+ if (PageHWPoison(page)) {
+ __ClearPageBuddy(page);
+ return;
+ }
+
/*
* Allow a burst of 60 reports, then keep quiet for that minute;
* or allow a steady drip of one report per second.
/*
* This page is about to be returned from the page allocator
*/
-static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
+static inline int check_new_page(struct page *page)
{
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
bad_page(page);
return 1;
}
+ return 0;
+}
+
+static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
+{
+ int i;
+
+ for (i = 0; i < (1 << order); i++) {
+ struct page *p = page + i;
+ if (unlikely(check_new_page(p)))
+ return 1;
+ }
set_page_private(page, 0);
set_page_refcounted(page);
* mapping->tree_lock (widely used, in set_page_dirty,
* in arch-dependent flush_dcache_mmap_lock,
* within inode_lock in __sync_single_inode)
+ *
+ * (code doesn't rely on that order so it could be switched around)
+ * ->tasklist_lock
+ * anon_vma->lock (memory_failure, collect_procs_anon)
+ * pte map lock
*/
#include <linux/mm.h>
* Getting a lock on a stable anon_vma from a page off the LRU is
* tricky: page_lock_anon_vma rely on RCU to guard against the races.
*/
-static struct anon_vma *page_lock_anon_vma(struct page *page)
+struct anon_vma *page_lock_anon_vma(struct page *page)
{
struct anon_vma *anon_vma;
unsigned long anon_mapping;
return NULL;
}
-static void page_unlock_anon_vma(struct anon_vma *anon_vma)
+void page_unlock_anon_vma(struct anon_vma *anon_vma)
{
spin_unlock(&anon_vma->lock);
rcu_read_unlock();
* if the page is not mapped into the page tables of this VMA. Only
* valid for normal file or anonymous VMAs.
*/
-static int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
+int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
{
unsigned long address;
pte_t *pte;
* repeatedly from either try_to_unmap_anon or try_to_unmap_file.
*/
static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
- int migration)
+ enum ttu_flags flags)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
* If it's recently referenced (perhaps page_referenced
* skipped over this mm) then we should reactivate it.
*/
- if (!migration) {
+ if (!(flags & TTU_IGNORE_MLOCK)) {
if (vma->vm_flags & VM_LOCKED) {
ret = SWAP_MLOCK;
goto out_unmap;
}
+ }
+ if (!(flags & TTU_IGNORE_ACCESS)) {
if (ptep_clear_flush_young_notify(vma, address, pte)) {
ret = SWAP_FAIL;
goto out_unmap;
/* Update high watermark before we lower rss */
update_hiwater_rss(mm);
- if (PageAnon(page)) {
+ if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
+ if (PageAnon(page))
+ dec_mm_counter(mm, anon_rss);
+ else
+ dec_mm_counter(mm, file_rss);
+ set_pte_at(mm, address, pte,
+ swp_entry_to_pte(make_hwpoison_entry(page)));
+ } else if (PageAnon(page)) {
swp_entry_t entry = { .val = page_private(page) };
if (PageSwapCache(page)) {
* pte. do_swap_page() will wait until the migration
* pte is removed and then restart fault handling.
*/
- BUG_ON(!migration);
+ BUG_ON(TTU_ACTION(flags) != TTU_MIGRATION);
entry = make_migration_entry(page, pte_write(pteval));
}
set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
BUG_ON(pte_file(*pte));
- } else if (PAGE_MIGRATION && migration) {
+ } else if (PAGE_MIGRATION && (TTU_ACTION(flags) == TTU_MIGRATION)) {
/* Establish migration entry for a file page */
swp_entry_t entry;
entry = make_migration_entry(page, pte_write(pteval));
* vm_flags for that VMA. That should be OK, because that vma shouldn't be
* 'LOCKED.
*/
-static int try_to_unmap_anon(struct page *page, int unlock, int migration)
+static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
{
struct anon_vma *anon_vma;
struct vm_area_struct *vma;
unsigned int mlocked = 0;
int ret = SWAP_AGAIN;
+ int unlock = TTU_ACTION(flags) == TTU_MUNLOCK;
if (MLOCK_PAGES && unlikely(unlock))
ret = SWAP_SUCCESS; /* default for try_to_munlock() */
continue; /* must visit all unlocked vmas */
ret = SWAP_MLOCK; /* saw at least one mlocked vma */
} else {
- ret = try_to_unmap_one(page, vma, migration);
+ ret = try_to_unmap_one(page, vma, flags);
if (ret == SWAP_FAIL || !page_mapped(page))
break;
}
/**
* try_to_unmap_file - unmap/unlock file page using the object-based rmap method
* @page: the page to unmap/unlock
- * @unlock: request for unlock rather than unmap [unlikely]
- * @migration: unmapping for migration - ignored if @unlock
+ * @flags: action and flags
*
* Find all the mappings of a page using the mapping pointer and the vma chains
* contained in the address_space struct it points to.
* vm_flags for that VMA. That should be OK, because that vma shouldn't be
* 'LOCKED.
*/
-static int try_to_unmap_file(struct page *page, int unlock, int migration)
+static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
{
struct address_space *mapping = page->mapping;
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
unsigned long max_nl_size = 0;
unsigned int mapcount;
unsigned int mlocked = 0;
+ int unlock = TTU_ACTION(flags) == TTU_MUNLOCK;
if (MLOCK_PAGES && unlikely(unlock))
ret = SWAP_SUCCESS; /* default for try_to_munlock() */
continue; /* must visit all vmas */
ret = SWAP_MLOCK;
} else {
- ret = try_to_unmap_one(page, vma, migration);
+ ret = try_to_unmap_one(page, vma, flags);
if (ret == SWAP_FAIL || !page_mapped(page))
goto out;
}
ret = SWAP_MLOCK; /* leave mlocked == 0 */
goto out; /* no need to look further */
}
- if (!MLOCK_PAGES && !migration && (vma->vm_flags & VM_LOCKED))
+ if (!MLOCK_PAGES && !(flags & TTU_IGNORE_MLOCK) &&
+ (vma->vm_flags & VM_LOCKED))
continue;
cursor = (unsigned long) vma->vm_private_data;
if (cursor > max_nl_cursor)
do {
list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if (!MLOCK_PAGES && !migration &&
+ if (!MLOCK_PAGES && !(flags & TTU_IGNORE_MLOCK) &&
(vma->vm_flags & VM_LOCKED))
continue;
cursor = (unsigned long) vma->vm_private_data;
/**
* try_to_unmap - try to remove all page table mappings to a page
* @page: the page to get unmapped
- * @migration: migration flag
+ * @flags: action and flags
*
* Tries to remove all the page table entries which are mapping this
* page, used in the pageout path. Caller must hold the page lock.
* SWAP_FAIL - the page is unswappable
* SWAP_MLOCK - page is mlocked.
*/
-int try_to_unmap(struct page *page, int migration)
+int try_to_unmap(struct page *page, enum ttu_flags flags)
{
int ret;
BUG_ON(!PageLocked(page));
if (PageAnon(page))
- ret = try_to_unmap_anon(page, 0, migration);
+ ret = try_to_unmap_anon(page, flags);
else
- ret = try_to_unmap_file(page, 0, migration);
+ ret = try_to_unmap_file(page, flags);
if (ret != SWAP_MLOCK && !page_mapped(page))
ret = SWAP_SUCCESS;
return ret;
VM_BUG_ON(!PageLocked(page) || PageLRU(page));
if (PageAnon(page))
- return try_to_unmap_anon(page, 1, 0);
+ return try_to_unmap_anon(page, TTU_MUNLOCK);
else
- return try_to_unmap_file(page, 1, 0);
+ return try_to_unmap_file(page, TTU_MUNLOCK);
}
if (pos + copied > inode->i_size)
i_size_write(inode, pos + copied);
- unlock_page(page);
set_page_dirty(page);
+ unlock_page(page);
page_cache_release(page);
return copied;
iput(inode);
return error;
}
- unlock_page(page);
inode->i_mapping->a_ops = &shmem_aops;
inode->i_op = &shmem_symlink_inode_operations;
kaddr = kmap_atomic(page, KM_USER0);
memcpy(kaddr, symname, len);
kunmap_atomic(kaddr, KM_USER0);
set_page_dirty(page);
+ unlock_page(page);
page_cache_release(page);
}
if (dir->i_mode & S_ISGID)
.write_end = shmem_write_end,
#endif
.migratepage = migrate_page,
+ .error_remove_page = generic_error_remove_page,
};
static const struct file_operations shmem_file_operations = {
struct swap_info_struct *p;
struct page *page = NULL;
- if (is_migration_entry(entry))
+ if (non_swap_entry(entry))
return 1;
p = swap_info_get(entry);
int count;
bool has_cache;
- if (is_migration_entry(entry))
+ if (non_swap_entry(entry))
return -EINVAL;
type = swp_type(entry);
* its lock, b) when a concurrent invalidate_mapping_pages got there first and
* c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
*/
-static void
+static int
truncate_complete_page(struct address_space *mapping, struct page *page)
{
if (page->mapping != mapping)
- return;
+ return -EIO;
if (page_has_private(page))
do_invalidatepage(page, 0);
remove_from_page_cache(page);
ClearPageMappedToDisk(page);
page_cache_release(page); /* pagecache ref */
+ return 0;
}
/*
return ret;
}
+int truncate_inode_page(struct address_space *mapping, struct page *page)
+{
+ if (page_mapped(page)) {
+ unmap_mapping_range(mapping,
+ (loff_t)page->index << PAGE_CACHE_SHIFT,
+ PAGE_CACHE_SIZE, 0);
+ }
+ return truncate_complete_page(mapping, page);
+}
+
+/*
+ * Used to get rid of pages on hardware memory corruption.
+ */
+int generic_error_remove_page(struct address_space *mapping, struct page *page)
+{
+ if (!mapping)
+ return -EINVAL;
+ /*
+ * Only punch for normal data pages for now.
+ * Handling other types like directories would need more auditing.
+ */
+ if (!S_ISREG(mapping->host->i_mode))
+ return -EIO;
+ return truncate_inode_page(mapping, page);
+}
+EXPORT_SYMBOL(generic_error_remove_page);
+
+/*
+ * Safely invalidate one page from its pagecache mapping.
+ * It only drops clean, unused pages. The page must be locked.
+ *
+ * Returns 1 if the page is successfully invalidated, otherwise 0.
+ */
+int invalidate_inode_page(struct page *page)
+{
+ struct address_space *mapping = page_mapping(page);
+ if (!mapping)
+ return 0;
+ if (PageDirty(page) || PageWriteback(page))
+ return 0;
+ if (page_mapped(page))
+ return 0;
+ return invalidate_complete_page(mapping, page);
+}
+
/**
* truncate_inode_pages - truncate range of pages specified by start & end byte offsets
* @mapping: mapping to truncate
unlock_page(page);
continue;
}
- if (page_mapped(page)) {
- unmap_mapping_range(mapping,
- (loff_t)page_index<<PAGE_CACHE_SHIFT,
- PAGE_CACHE_SIZE, 0);
- }
- truncate_complete_page(mapping, page);
+ truncate_inode_page(mapping, page);
unlock_page(page);
}
pagevec_release(&pvec);
break;
lock_page(page);
wait_on_page_writeback(page);
- if (page_mapped(page)) {
- unmap_mapping_range(mapping,
- (loff_t)page->index<<PAGE_CACHE_SHIFT,
- PAGE_CACHE_SIZE, 0);
- }
+ truncate_inode_page(mapping, page);
if (page->index > next)
next = page->index;
next++;
- truncate_complete_page(mapping, page);
unlock_page(page);
}
pagevec_release(&pvec);
if (lock_failed)
continue;
- if (PageDirty(page) || PageWriteback(page))
- goto unlock;
- if (page_mapped(page))
- goto unlock;
- ret += invalidate_complete_page(mapping, page);
-unlock:
+ ret += invalidate_inode_page(page);
+
unlock_page(page);
if (next > end)
break;
* processes. Try to unmap it here.
*/
if (page_mapped(page) && mapping) {
- switch (try_to_unmap(page, 0)) {
+ switch (try_to_unmap(page, TTU_UNMAP)) {
case SWAP_FAIL:
goto activate_locked;
case SWAP_AGAIN:
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff