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Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 

* '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
  ...
This commit is contained in:
Linus Torvalds 2009-09-24 07:53:22 -07:00
parent cd6045138e 465fdd97cb
commit db16826367
40 changed files with 1331 additions and 68 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
Documentation/filesystems/vfs.txt
View File

@ -536,6 +536,7 @@ struct address_space_operations {
/* 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.
@ -694,6 +695,12 @@ struct address_space_operations {
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
===============

41
Documentation/sysctl/vm.txt
View File

@ -32,6 +32,8 @@ Currently, these files are in /proc/sys/vm:
- 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
@ -53,7 +55,6 @@ Currently, these files are in /proc/sys/vm:
- vfs_cache_pressure
- zone_reclaim_mode
==============================================================
block_dump
@ -275,6 +276,44 @@ e.g., up to one or two maps per allocation.
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:

19
arch/x86/mm/fault.c
View File

@ -167,6 +167,7 @@ force_sig_info_fault(int si_signo, int si_code, unsigned long address,
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);
}
@ -790,10 +791,12 @@ out_of_memory(struct pt_regs *regs, unsigned long error_code,
}
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);
@ -809,7 +812,15 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
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
@ -819,8 +830,8 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
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();
}

1
fs/btrfs/inode.c
View File

@ -5269,6 +5269,7 @@ static const struct address_space_operations btrfs_aops = {
.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 = {

2
fs/ext2/inode.c
View File

@ -819,6 +819,7 @@ const struct address_space_operations ext2_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 = {
@ -837,6 +838,7 @@ const struct address_space_operations ext2_nobh_aops = {
.direct_IO = ext2_direct_IO,
.writepages = ext2_writepages,
.migratepage = buffer_migrate_page,
.error_remove_page = generic_error_remove_page,
};
/*

3
fs/ext3/inode.c
View File

@ -1830,6 +1830,7 @@ static const struct address_space_operations ext3_ordered_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_writeback_aops = {
@ -1845,6 +1846,7 @@ 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 = {
@ -1859,6 +1861,7 @@ 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)

4
fs/ext4/inode.c
View File

@ -3386,6 +3386,7 @@ static const struct address_space_operations ext4_ordered_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_writeback_aops = {
@ -3401,6 +3402,7 @@ 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 = {
@ -3415,6 +3417,7 @@ 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 = {
@ -3431,6 +3434,7 @@ 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)

3
fs/gfs2/aops.c
View File

@ -1135,6 +1135,7 @@ static const struct address_space_operations gfs2_writeback_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_ordered_aops = {
@ -1151,6 +1152,7 @@ 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 = {
@ -1166,6 +1168,7 @@ 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)

1
fs/nfs/file.c
View File

@ -525,6 +525,7 @@ const struct address_space_operations nfs_file_aops = {
.direct_IO = nfs_direct_IO,
.migratepage = nfs_migrate_page,
.launder_page = nfs_launder_page,
.error_remove_page = generic_error_remove_page,
};
/*

2
fs/ntfs/aops.c
View File

@ -1550,6 +1550,7 @@ const struct address_space_operations ntfs_aops = {
.migratepage = buffer_migrate_page, /* Move a page cache page from
one physical page to an
other. */
.error_remove_page = generic_error_remove_page,
};
/**
@ -1569,6 +1570,7 @@ const struct address_space_operations ntfs_mst_aops = {
.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

1
fs/ocfs2/aops.c
View File

@ -2022,4 +2022,5 @@ const struct address_space_operations ocfs2_aops = {
.releasepage = ocfs2_releasepage,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};

9
fs/proc/meminfo.c
View File

@ -97,7 +97,11 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
"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),
@ -144,6 +148,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
(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);

1
fs/xfs/linux-2.6/xfs_aops.c
View File

@ -1635,4 +1635,5 @@ const struct address_space_operations xfs_address_space_operations = {
.direct_IO = xfs_vm_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};

1
include/asm-generic/mman-common.h
View File

@ -34,6 +34,7 @@
#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 */

8
include/asm-generic/siginfo.h
View File

@ -82,6 +82,7 @@ typedef struct siginfo {
#ifdef __ARCH_SI_TRAPNO
int _trapno; /* TRAP # which caused the signal */
#endif
short _addr_lsb; /* LSB of the reported address */
} _sigfault;
/* SIGPOLL */
@ -112,6 +113,7 @@ typedef struct siginfo {
#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
@ -192,7 +194,11 @@ typedef struct siginfo {
#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

1
include/linux/fs.h
View File

@ -595,6 +595,7 @@ struct address_space_operations {
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 *);
};
/*

15
include/linux/mm.h
View File

@ -695,11 +695,12 @@ static inline int page_mapped(struct page *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.
@ -794,6 +795,11 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping,
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);
@ -1308,5 +1314,12 @@ void vmemmap_populate_print_last(void);
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 */

17
include/linux/page-flags.h
View File

@ -51,6 +51,9 @@
* 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!
*/
/*
@ -101,6 +104,9 @@ enum pageflags {
#endif
#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,
@ -269,6 +275,15 @@ PAGEFLAG(Uncached, uncached)
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);
@ -393,7 +408,7 @@ static inline void __ClearPageTail(struct page *page)
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.

2
include/linux/prctl.h
View File

@ -88,4 +88,6 @@
#define PR_TASK_PERF_EVENTS_DISABLE 31
#define PR_TASK_PERF_EVENTS_ENABLE 32
#define PR_MCE_KILL 33
#endif /* _LINUX_PRCTL_H */

21
include/linux/rmap.h
View File

@ -81,7 +81,19 @@ static inline void page_dup_rmap(struct page *page)
*/
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
@ -108,6 +120,13 @@ int page_mkclean(struct 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)

2
include/linux/sched.h
View File

@ -1734,6 +1734,7 @@ extern cputime_t task_gtime(struct task_struct *p);
#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 */
@ -1753,6 +1754,7 @@ extern cputime_t task_gtime(struct task_struct *p);
#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 */

34
include/linux/swap.h
View File

@ -34,15 +34,37 @@ static inline int current_is_kswapd(void)
* 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)

38
include/linux/swapops.h
View File

@ -131,3 +131,41 @@ static inline int is_write_migration_entry(swp_entry_t entry)
#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

22
kernel/sys.c
View File

@ -1542,6 +1542,28 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
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;

25
kernel/sysctl.c
View File

@ -1398,6 +1398,31 @@ static struct ctl_table vm_table[] = {
.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

14
mm/Kconfig
View File

@ -245,6 +245,20 @@ config DEFAULT_MMAP_MIN_ADDR
/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

2
mm/Makefile
View File

@ -41,5 +41,7 @@ obj-$(CONFIG_SMP) += allocpercpu.o
endif
obj-$(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

4
mm/filemap.c
View File

@ -104,6 +104,10 @@
*
* ->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
*/
/*

41
mm/hwpoison-inject.c Normal file
View File

@ -0,0 +1,41 @@
/* 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");

30
mm/madvise.c
View File

@ -218,6 +218,32 @@ static long madvise_remove(struct vm_area_struct *vma,
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)
@ -308,6 +334,10 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, 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;

832
mm/memory-failure.c Normal file
View File

@ -0,0 +1,832 @@
/*
* 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);
}

24
mm/memory.c
View File

@ -1325,7 +1325,8 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
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();
}
@ -2559,8 +2560,15 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
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);
@ -2584,6 +2592,10 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
/* 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);
@ -2760,6 +2772,12 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
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.

2
mm/migrate.c
View File

@ -675,7 +675,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
}
/* 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))

7
mm/page-writeback.c
View File

@ -1149,6 +1149,13 @@ int redirty_page_for_writepage(struct writeback_control *wbc, struct page *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.
*/

20
mm/page_alloc.c
View File

@ -234,6 +234,12 @@ static void bad_page(struct page *page)
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.
@ -666,7 +672,7 @@ static inline void expand(struct zone *zone, struct page *page,
/*
* 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) |
@ -675,6 +681,18 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
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);

60
mm/rmap.c
View File

@ -36,6 +36,11 @@
* 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>
@ -191,7 +196,7 @@ void __init anon_vma_init(void)
* 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;
@ -211,7 +216,7 @@ out:
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();
@ -311,7 +316,7 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm,
* 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;
@ -756,7 +761,7 @@ void page_remove_rmap(struct page *page)
* 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;
@ -778,11 +783,13 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
* 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;
@ -800,7 +807,14 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
/* 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)) {
@ -822,12 +836,12 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
* 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));
@ -996,12 +1010,13 @@ static int try_to_mlock_page(struct page *page, struct vm_area_struct *vma)
* 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() */
@ -1017,7 +1032,7 @@ static int try_to_unmap_anon(struct page *page, int unlock, int migration)
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;
}
@ -1041,8 +1056,7 @@ static int try_to_unmap_anon(struct page *page, int unlock, int migration)
/**
* 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.
@ -1054,7 +1068,7 @@ static int try_to_unmap_anon(struct page *page, int unlock, int migration)
* 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);
@ -1066,6 +1080,7 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration)
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() */
@ -1078,7 +1093,7 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration)
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;
}
@ -1103,7 +1118,8 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration)
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)
@ -1137,7 +1153,7 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration)
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;
@ -1177,7 +1193,7 @@ out:
/**
* 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.
@ -1188,16 +1204,16 @@ out:
* 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;
@ -1222,8 +1238,8 @@ int try_to_munlock(struct page *page)
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);
}

5
mm/shmem.c
View File

@ -1633,8 +1633,8 @@ shmem_write_end(struct file *file, struct address_space *mapping,
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;
@ -1971,13 +1971,13 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
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)
@ -2420,6 +2420,7 @@ static const struct address_space_operations shmem_aops = {
.write_end = shmem_write_end,
#endif
.migratepage = migrate_page,
.error_remove_page = generic_error_remove_page,
};
static const struct file_operations shmem_file_operations = {

4
mm/swapfile.c
View File

@ -699,7 +699,7 @@ int free_swap_and_cache(swp_entry_t entry)
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);
@ -2085,7 +2085,7 @@ static int __swap_duplicate(swp_entry_t entry, bool cache)
int count;
bool has_cache;
if (is_migration_entry(entry))
if (non_swap_entry(entry))
return -EINVAL;
type = swp_type(entry);

72
mm/truncate.c
View File

@ -93,11 +93,11 @@ EXPORT_SYMBOL(cancel_dirty_page);
* 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);
@ -108,6 +108,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
remove_from_page_cache(page);
ClearPageMappedToDisk(page);
page_cache_release(page); /* pagecache ref */
return 0;
}
/*
@ -135,6 +136,51 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
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
@ -196,12 +242,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
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);
@ -238,15 +279,10 @@ void truncate_inode_pages_range(struct address_space *mapping,
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);
@ -311,12 +347,8 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
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;

2
mm/vmscan.c
View File

@ -663,7 +663,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* 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: