From 7329bbeb92740f35d64a8860ae7837ff4db27fe0 Mon Sep 17 00:00:00 2001 From: Tony Luck Date: Tue, 13 Dec 2011 09:27:58 -0800 Subject: [PATCH] HWPOISON: Add code to handle "action required" errors. Add new flag bit "MF_ACTION_REQUIRED" to be used by machine check code to force a signal with si_code = BUS_MCEERR_AR in the case where the error occurs in processor execution context. Pass the flags argument along call chain: memory_failure() hwpoison_user_mappings() kill_procs() kill_proc() Drop the "_ao" suffix from kill_procs_ao() and kill_proc_ao() since they can now handle "action required" as well as "action optional" errors. Acked-by: Borislav Petkov Signed-off-by: Tony Luck --- include/linux/mm.h | 1 + mm/memory-failure.c | 50 ++++++++++++++++++++++++++------------------- 2 files changed, 30 insertions(+), 21 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index bcc523474724..bf169ca69812 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1606,6 +1606,7 @@ void vmemmap_populate_print_last(void); enum mf_flags { MF_COUNT_INCREASED = 1 << 0, + MF_ACTION_REQUIRED = 1 << 1, }; 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 ab259bb0adc5..95fd307ebb30 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -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; } @@ -1148,7 +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;