From 6751ed65dc6642af64f7b8a440a75563c8aab7ae Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Wed, 11 Jul 2012 10:20:47 -0700 Subject: [PATCH] x86/mce: Fix siginfo_t->si_addr value for non-recoverable memory faults In commit dad1743e5993f1 ("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 Acked-by: Borislav Petkov Cc: stable@kernel.org # 3.4+ --- arch/x86/kernel/cpu/mcheck/mce.c | 6 ++++-- include/linux/mm.h | 1 + mm/memory-failure.c | 14 ++++++++------ 3 files changed, 13 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c index da27c5d..c46ed49 100644 --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -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); } diff --git a/include/linux/mm.h b/include/linux/mm.h index b36d08c..f9f279c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -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); diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ab1e714..de4ce70 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -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; -- 2.7.4