| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.15 027/139] mm/memory-failure.c-failure: send right signal code to correct thread | Date | Sat, 28 Jun 2014 10:46:28 -0700 |
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3.15-stable review patch. If anyone has any objections, please let me know.
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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 @@ -204,9 +204,9 @@ 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
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