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MCE recovery (data path only)

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Merge tag 'mce-recovery-for-tip' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras into x86/mce

Implement MCE recovery for the data load error path and assorted cleanups.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2012-01-26 11:40:13 +01:00
commit 4e9f44ba29
7 changed files with 197 additions and 106 deletions
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16
arch/x86/kernel/cpu/mcheck/mce-severity.c
View File

@ -54,6 +54,7 @@ static struct severity {
#define MASK(x, y) .mask = x, .result = y
#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
#define MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
#define MCACOD 0xffff
MCESEV(
@ -102,11 +103,24 @@ static struct severity {
SER, BITCLR(MCI_STATUS_S)
),
/* AR add known MCACODs here */
MCESEV(
PANIC, "Action required with lost events",
SER, BITSET(MCI_STATUS_OVER|MCI_UC_SAR)
),
/* known AR MCACODs: */
#ifdef CONFIG_MEMORY_FAILURE
MCESEV(
KEEP, "HT thread notices Action required: data load error",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|0x0134),
MCGMASK(MCG_STATUS_EIPV, 0)
),
MCESEV(
AR, "Action required: data load error",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|0x0134),
USER
),
#endif
MCESEV(
PANIC, "Action required: unknown MCACOD",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR)

179
arch/x86/kernel/cpu/mcheck/mce.c
View File

@ -540,6 +540,27 @@ static void mce_report_event(struct pt_regs *regs)
irq_work_queue(&__get_cpu_var(mce_irq_work));
}
/*
* Read ADDR and MISC registers.
*/
static void mce_read_aux(struct mce *m, int i)
{
if (m->status & MCI_STATUS_MISCV)
m->misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
if (m->status & MCI_STATUS_ADDRV) {
m->addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
/*
* Mask the reported address by the reported granularity.
*/
if (mce_ser && (m->status & MCI_STATUS_MISCV)) {
u8 shift = MCI_MISC_ADDR_LSB(m->misc);
m->addr >>= shift;
m->addr <<= shift;
}
}
}
DEFINE_PER_CPU(unsigned, mce_poll_count);
/*
@ -590,10 +611,7 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
(m.status & (mce_ser ? MCI_STATUS_S : MCI_STATUS_UC)))
continue;
if (m.status & MCI_STATUS_MISCV)
m.misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
if (m.status & MCI_STATUS_ADDRV)
m.addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
mce_read_aux(&m, i);
if (!(flags & MCP_TIMESTAMP))
m.tsc = 0;
@ -916,6 +934,49 @@ static void mce_clear_state(unsigned long *toclear)
}
}
/*
* Need to save faulting physical address associated with a process
* in the machine check handler some place where we can grab it back
* later in mce_notify_process()
*/
#define MCE_INFO_MAX 16
struct mce_info {
atomic_t inuse;
struct task_struct *t;
__u64 paddr;
} mce_info[MCE_INFO_MAX];
static void mce_save_info(__u64 addr)
{
struct mce_info *mi;
for (mi = mce_info; mi < &mce_info[MCE_INFO_MAX]; mi++) {
if (atomic_cmpxchg(&mi->inuse, 0, 1) == 0) {
mi->t = current;
mi->paddr = addr;
return;
}
}
mce_panic("Too many concurrent recoverable errors", NULL, NULL);
}
static struct mce_info *mce_find_info(void)
{
struct mce_info *mi;
for (mi = mce_info; mi < &mce_info[MCE_INFO_MAX]; mi++)
if (atomic_read(&mi->inuse) && mi->t == current)
return mi;
return NULL;
}
static void mce_clear_info(struct mce_info *mi)
{
atomic_set(&mi->inuse, 0);
}
/*
* The actual machine check handler. This only handles real
* exceptions when something got corrupted coming in through int 18.
@ -969,7 +1030,9 @@ void do_machine_check(struct pt_regs *regs, long error_code)
barrier();
/*
* When no restart IP must always kill or panic.
* When no restart IP might need to kill or panic.
* Assume the worst for now, but if we find the
* severity is MCE_AR_SEVERITY we have other options.
*/
if (!(m.mcgstatus & MCG_STATUS_RIPV))
kill_it = 1;
@ -1023,16 +1086,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
continue;
}
/*
* Kill on action required.
*/
if (severity == MCE_AR_SEVERITY)
kill_it = 1;
if (m.status & MCI_STATUS_MISCV)
m.misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
if (m.status & MCI_STATUS_ADDRV)
m.addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
mce_read_aux(&m, i);
/*
* Action optional error. Queue address for later processing.
@ -1052,6 +1106,9 @@ void do_machine_check(struct pt_regs *regs, long error_code)
}
}
/* mce_clear_state will clear *final, save locally for use later */
m = *final;
if (!no_way_out)
mce_clear_state(toclear);
@ -1063,27 +1120,22 @@ void do_machine_check(struct pt_regs *regs, long error_code)
no_way_out = worst >= MCE_PANIC_SEVERITY;
/*
* If we have decided that we just CAN'T continue, and the user
* has not set tolerant to an insane level, give up and die.
*
* This is mainly used in the case when the system doesn't
* support MCE broadcasting or it has been disabled.
* At insane "tolerant" levels we take no action. Otherwise
* we only die if we have no other choice. For less serious
* issues we try to recover, or limit damage to the current
* process.
*/
if (no_way_out && tolerant < 3)
mce_panic("Fatal machine check on current CPU", final, msg);
/*
* If the error seems to be unrecoverable, something should be
* done. Try to kill as little as possible. If we can kill just
* one task, do that. If the user has set the tolerance very
* high, don't try to do anything at all.
*/
if (kill_it && tolerant < 3)
force_sig(SIGBUS, current);
/* notify userspace ASAP */
set_thread_flag(TIF_MCE_NOTIFY);
if (tolerant < 3) {
if (no_way_out)
mce_panic("Fatal machine check on current CPU", &m, msg);
if (worst == MCE_AR_SEVERITY) {
/* schedule action before return to userland */
mce_save_info(m.addr);
set_thread_flag(TIF_MCE_NOTIFY);
} else if (kill_it) {
force_sig(SIGBUS, current);
}
}
if (worst > 0)
mce_report_event(regs);
@ -1094,34 +1146,57 @@ out:
}
EXPORT_SYMBOL_GPL(do_machine_check);
/* dummy to break dependency. actual code is in mm/memory-failure.c */
void __attribute__((weak)) memory_failure(unsigned long pfn, int vector)
#ifndef CONFIG_MEMORY_FAILURE
int memory_failure(unsigned long pfn, int vector, int flags)
{
printk(KERN_ERR "Action optional memory failure at %lx ignored\n", pfn);
/* mce_severity() should not hand us an ACTION_REQUIRED error */
BUG_ON(flags & MF_ACTION_REQUIRED);
printk(KERN_ERR "Uncorrected memory error in page 0x%lx ignored\n"
"Rebuild kernel with CONFIG_MEMORY_FAILURE=y for smarter handling\n", pfn);
return 0;
}
#endif
/*
* Called after mce notification in process context. This code
* is allowed to sleep. Call the high level VM handler to process
* any corrupted pages.
* Assume that the work queue code only calls this one at a time
* per CPU.
* Note we don't disable preemption, so this code might run on the wrong
* CPU. In this case the event is picked up by the scheduled work queue.
* This is merely a fast path to expedite processing in some common
* cases.
* Called in process context that interrupted by MCE and marked with
* TIF_MCE_NOTIFY, just before returning to erroneous userland.
* This code is allowed to sleep.
* Attempt possible recovery such as calling the high level VM handler to
* process any corrupted pages, and kill/signal current process if required.
* Action required errors are handled here.
*/
void mce_notify_process(void)
{
unsigned long pfn;
mce_notify_irq();
while (mce_ring_get(&pfn))
memory_failure(pfn, MCE_VECTOR);
struct mce_info *mi = mce_find_info();
if (!mi)
mce_panic("Lost physical address for unconsumed uncorrectable error", NULL, NULL);
pfn = mi->paddr >> PAGE_SHIFT;
clear_thread_flag(TIF_MCE_NOTIFY);
pr_err("Uncorrected hardware memory error in user-access at %llx",
mi->paddr);
if (memory_failure(pfn, MCE_VECTOR, MF_ACTION_REQUIRED) < 0) {
pr_err("Memory error not recovered");
force_sig(SIGBUS, current);
}
mce_clear_info(mi);
}
/*
* Action optional processing happens here (picking up
* from the list of faulting pages that do_machine_check()
* placed into the "ring").
*/
static void mce_process_work(struct work_struct *dummy)
{
mce_notify_process();
unsigned long pfn;
while (mce_ring_get(&pfn))
memory_failure(pfn, MCE_VECTOR, 0);
}
#ifdef CONFIG_X86_MCE_INTEL
@ -1211,8 +1286,6 @@ int mce_notify_irq(void)
/* Not more than two messages every minute */
static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
clear_thread_flag(TIF_MCE_NOTIFY);
if (test_and_clear_bit(0, &mce_need_notify)) {
/* wake processes polling /dev/mcelog */
wake_up_interruptible(&mce_chrdev_wait);

2
drivers/base/memory.c
View File

@ -466,7 +466,7 @@ store_hard_offline_page(struct device *dev,
if (strict_strtoull(buf, 0, &pfn) < 0)
return -EINVAL;
pfn >>= PAGE_SHIFT;
ret = __memory_failure(pfn, 0, 0);
ret = memory_failure(pfn, 0, 0);
return ret ? ret : count;
}

4
include/linux/mm.h
View File

@ -1598,9 +1598,9 @@ void vmemmap_populate_print_last(void);
enum mf_flags {
MF_COUNT_INCREASED = 1 << 0,
MF_ACTION_REQUIRED = 1 << 1,
};
extern void memory_failure(unsigned long pfn, int trapno);
extern int __memory_failure(unsigned long pfn, int trapno, int flags);
extern int memory_failure(unsigned long pfn, int trapno, int flags);
extern void memory_failure_queue(unsigned long pfn, int trapno, int flags);
extern int unpoison_memory(unsigned long pfn);
extern int sysctl_memory_failure_early_kill;

4
mm/hwpoison-inject.c
View File

@ -45,7 +45,7 @@ static int hwpoison_inject(void *data, u64 val)
* do a racy check with elevated page count, to make sure PG_hwpoison
* will only be set for the targeted owner (or on a free page).
* We temporarily take page lock for try_get_mem_cgroup_from_page().
* __memory_failure() will redo the check reliably inside page lock.
* memory_failure() will redo the check reliably inside page lock.
*/
lock_page(hpage);
err = hwpoison_filter(hpage);
@ -55,7 +55,7 @@ static int hwpoison_inject(void *data, u64 val)
inject:
printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
return __memory_failure(pfn, 18, MF_COUNT_INCREASED);
return memory_failure(pfn, 18, MF_COUNT_INCREASED);
}
static int hwpoison_unpoison(void *data, u64 val)

2
mm/madvise.c
View File

@ -251,7 +251,7 @@ static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end)
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, MF_COUNT_INCREASED);
memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED);
}
return ret;
}

96
mm/memory-failure.c
View File

@ -187,33 +187,40 @@ int hwpoison_filter(struct page *p)
EXPORT_SYMBOL_GPL(hwpoison_filter);
/*
* Send all the processes who have the page mapped an ``action optional''
* signal.
* Send all the processes who have the page mapped a signal.
* ``action optional'' if they are not immediately affected by the error
* ``action required'' if error happened in current execution context
*/
static int kill_proc_ao(struct task_struct *t, unsigned long addr, int trapno,
unsigned long pfn, struct page *page)
static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
unsigned long pfn, struct page *page, int flags)
{
struct siginfo si;
int ret;
printk(KERN_ERR
"MCE %#lx: Killing %s:%d early due to hardware memory corruption\n",
"MCE %#lx: Killing %s:%d 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 = compound_trans_order(compound_head(page)) + 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 no one will do that?
*/
ret = send_sig_info(SIGBUS, &si, t); /* synchronous? */
if ((flags & MF_ACTION_REQUIRED) && t == current) {
si.si_code = BUS_MCEERR_AR;
ret = force_sig_info(SIGBUS, &si, t);
} else {
/*
* 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 no one will do that?
*/
si.si_code = BUS_MCEERR_AO;
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);
@ -338,8 +345,9 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
* 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, struct page *page, unsigned long pfn)
static void kill_procs(struct list_head *to_kill, int doit, int trapno,
int fail, struct page *page, unsigned long pfn,
int flags)
{
struct to_kill *tk, *next;
@ -363,8 +371,8 @@ static void kill_procs_ao(struct list_head *to_kill, int doit, int trapno,
* check for that, but we need to tell the
* process anyways.
*/
else if (kill_proc_ao(tk->tsk, tk->addr, trapno,
pfn, page) < 0)
else if (kill_proc(tk->tsk, tk->addr, trapno,
pfn, page, flags) < 0)
printk(KERN_ERR
"MCE %#lx: Cannot send advisory machine check signal to %s:%d\n",
pfn, tk->tsk->comm, tk->tsk->pid);
@ -844,7 +852,7 @@ static int page_action(struct page_state *ps, struct page *p,
* the pages and send SIGBUS to the processes if the data was dirty.
*/
static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
int trapno)
int trapno, int flags)
{
enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
struct address_space *mapping;
@ -962,8 +970,8 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
* use a more force-full uncatchable kill to prevent
* any accesses to the poisoned memory.
*/
kill_procs_ao(&tokill, !!PageDirty(ppage), trapno,
ret != SWAP_SUCCESS, p, pfn);
kill_procs(&tokill, !!PageDirty(ppage), trapno,
ret != SWAP_SUCCESS, p, pfn, flags);
return ret;
}
@ -984,7 +992,25 @@ static void clear_page_hwpoison_huge_page(struct page *hpage)
ClearPageHWPoison(hpage + i);
}
int __memory_failure(unsigned long pfn, int trapno, int flags)
/**
* 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.
* @flags: fine tune action taken
*
* 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.
*/
int memory_failure(unsigned long pfn, int trapno, int flags)
{
struct page_state *ps;
struct page *p;
@ -1130,7 +1156,7 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
* Now take care of user space mappings.
* Abort on fail: __delete_from_page_cache() assumes unmapped page.
*/
if (hwpoison_user_mappings(p, pfn, trapno) != SWAP_SUCCESS) {
if (hwpoison_user_mappings(p, pfn, trapno, flags) != SWAP_SUCCESS) {
printk(KERN_ERR "MCE %#lx: cannot unmap page, give up\n", pfn);
res = -EBUSY;
goto out;
@ -1156,29 +1182,7 @@ out:
unlock_page(hpage);
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);
}
EXPORT_SYMBOL_GPL(memory_failure);
#define MEMORY_FAILURE_FIFO_ORDER 4
#define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER)
@ -1251,7 +1255,7 @@ static void memory_failure_work_func(struct work_struct *work)
spin_unlock_irqrestore(&mf_cpu->lock, proc_flags);
if (!gotten)
break;
__memory_failure(entry.pfn, entry.trapno, entry.flags);
memory_failure(entry.pfn, entry.trapno, entry.flags);
}
}