Commit 7329bbeb authored by Tony Luck's avatar Tony Luck
Browse files

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: default avatarBorislav Petkov <bp@amd64.org>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent cd42f4a3

include/linux/mm.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

mm/memory-failure.c

+29 −21
Original line number Diff line number Diff line
@@ -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;



	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;

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