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x86/mce: Fix siginfo_t->si_addr value for non-recoverable memory faults

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In commit dad1743e59 ("x86/mce: Only restart instruction after machine
check recovery if it is safe") we fixed mce_notify_process() to force a
signal to the current process if it was not restartable (RIPV bit not
set in MCG_STATUS). But doing it here means that the process doesn't
get told the virtual address of the fault via siginfo_t->si_addr. This
would prevent application level recovery from the fault.

Make a new MF_MUST_KILL flag bit for memory_failure() et al. to use so
that we will provide the right information with the signal.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: stable@kernel.org    # 3.4+
This commit is contained in:
Tony Luck 2012-07-11 10:20:47 -07:00
parent 6887a4131d
commit 6751ed65dc
3 changed files with 13 additions and 8 deletions
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6
arch/x86/kernel/cpu/mcheck/mce.c
View file

@ -1186,6 +1186,7 @@ void mce_notify_process(void)
{
unsigned long pfn;
struct mce_info *mi = mce_find_info();
int flags = MF_ACTION_REQUIRED;
if (!mi)
mce_panic("Lost physical address for unconsumed uncorrectable error", NULL, NULL);
@ -1200,8 +1201,9 @@ void mce_notify_process(void)
* doomed. We still need to mark the page as poisoned and alert any
* other users of the page.
*/
if (memory_failure(pfn, MCE_VECTOR, MF_ACTION_REQUIRED) < 0 ||
mi->restartable == 0) {
if (!mi->restartable)
flags |= MF_MUST_KILL;
if (memory_failure(pfn, MCE_VECTOR, flags) < 0) {
pr_err("Memory error not recovered");
force_sig(SIGBUS, current);
}

1
include/linux/mm.h
View file

@ -1591,6 +1591,7 @@ void vmemmap_populate_print_last(void);
enum mf_flags {
MF_COUNT_INCREASED = 1 << 0,
MF_ACTION_REQUIRED = 1 << 1,
MF_MUST_KILL = 1 << 2,
};
extern int memory_failure(unsigned long pfn, int trapno, int flags);
extern void memory_failure_queue(unsigned long pfn, int trapno, int flags);

14
mm/memory-failure.c
View file

@ -345,14 +345,14 @@ 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(struct list_head *to_kill, int doit, int trapno,
static void kill_procs(struct list_head *to_kill, int forcekill, int trapno,
int fail, struct page *page, unsigned long pfn,
int flags)
{
struct to_kill *tk, *next;
list_for_each_entry_safe (tk, next, to_kill, nd) {
if (doit) {
if (forcekill) {
/*
* In case something went wrong with munmapping
* make sure the process doesn't catch the
@ -858,7 +858,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
struct address_space *mapping;
LIST_HEAD(tokill);
int ret;
int kill = 1;
int kill = 1, forcekill;
struct page *hpage = compound_head(p);
struct page *ppage;
@ -888,7 +888,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
* be called inside page lock (it's recommended but not enforced).
*/
mapping = page_mapping(hpage);
if (!PageDirty(hpage) && mapping &&
if (!(flags & MF_MUST_KILL) && !PageDirty(hpage) && mapping &&
mapping_cap_writeback_dirty(mapping)) {
if (page_mkclean(hpage)) {
SetPageDirty(hpage);
@ -965,12 +965,14 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
* 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
* was dirty or the process is not restartable,
* 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(&tokill, !!PageDirty(ppage), trapno,
forcekill = PageDirty(ppage) || (flags & MF_MUST_KILL);
kill_procs(&tokill, forcekill, trapno,
ret != SWAP_SUCCESS, p, pfn, flags);
return ret;