Commit a70ffcac authored by Tony Luck's avatar Tony Luck Committed by Linus Torvalds

mm/memory-failure.c-failure: send right signal code to correct thread

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: default avatarTony Luck <>
Signed-off-by: default avatarNaoya Horiguchi <>
Reported-by: default avatarOtto Bruggeman <>
Cc: Andi Kleen <>
Cc: Borislav Petkov <>
Cc: Chen Gong <>
Cc: <>	[3.2+]
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent d2f31028
......@@ -204,9 +204,9 @@ static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
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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