| From a70ffcac741d31a406c1d2b832ae43d658e7e1cf Mon Sep 17 00:00:00 2001 |
| From: Tony Luck <tony.luck@intel.com> |
| Date: Wed, 4 Jun 2014 16:10:59 -0700 |
| Subject: mm/memory-failure.c-failure: send right signal code to correct thread |
| |
| From: Tony Luck <tony.luck@intel.com> |
| |
| commit a70ffcac741d31a406c1d2b832ae43d658e7e1cf upstream. |
| |
| When a thread in a multi-threaded application hits a machine check because |
| of an uncorrectable error in memory - we want to send the SIGBUS with |
| si.si_code = BUS_MCEERR_AR to that thread. Currently we fail to do that |
| if the active thread is not the primary thread in the process. |
| collect_procs() just finds primary threads and this test: |
| |
| if ((flags & MF_ACTION_REQUIRED) && t == current) { |
| |
| will see that the thread we found isn't the current thread and so send a |
| si.si_code = BUS_MCEERR_AO to the primary (and nothing to the active |
| thread at this time). |
| |
| We can fix this by checking whether "current" shares the same mm with the |
| process that collect_procs() said owned the page. If so, we send the |
| SIGBUS to current (with code BUS_MCEERR_AR). |
| |
| Signed-off-by: Tony Luck <tony.luck@intel.com> |
| Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> |
| Reported-by: Otto Bruggeman <otto.g.bruggeman@intel.com> |
| Cc: Andi Kleen <andi@firstfloor.org> |
| Cc: Borislav Petkov <bp@suse.de> |
| Cc: Chen Gong <gong.chen@linux.jf.intel.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/memory-failure.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/mm/memory-failure.c |
| +++ b/mm/memory-failure.c |
| @@ -208,9 +208,9 @@ static int kill_proc(struct task_struct |
| #endif |
| si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT; |
| |
| - if ((flags & MF_ACTION_REQUIRED) && t == current) { |
| + if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) { |
| si.si_code = BUS_MCEERR_AR; |
| - ret = force_sig_info(SIGBUS, &si, t); |
| + ret = force_sig_info(SIGBUS, &si, current); |
| } else { |
| /* |
| * Don't use force here, it's convenient if the signal |
