[PATCH V2] mm, memory_failure: don't send BUS_MCEERR_AO for action required error

[Wetp Zhang]

Some processes dont't want to be killed early, but in "Action Required"
case, those also may be killed by BUS_MCEERR_AO when sharing memory
with other which is accessing the fail memory.
And sending SIGBUS with BUS_MCEERR_AO for action required error is
strange, so ignore the non-current processes here.

Suggested-by: Naoya Horiguchi 
Signed-off-by: Wetp Zhang 
---
 mm/memory-failure.c | 15 +--
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index a96364be8ab4..dd3862fcf2e9 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -210,14 +210,17 @@ static int kill_proc(struct to_kill *tk, unsigned long 
pfn, int flags)
 {
struct task_struct *t = tk->tsk;
short addr_lsb = tk->size_shift;
-   int ret;
+   int ret = 0;
 
-   pr_err("Memory failure: %#lx: Sending SIGBUS to %s:%d due to hardware 
memory corruption\n",
-   pfn, t->comm, t->pid);
+   if ((t->mm == current->mm) || !(flags & MF_ACTION_REQUIRED))
+   pr_err("Memory failure: %#lx: Sending SIGBUS to %s:%d due to 
hardware memory corruption\n",
+   pfn, t->comm, t->pid);
 
-   if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) {
-   ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)tk->addr,
-  addr_lsb);
+   if (flags & MF_ACTION_REQUIRED) {
+   if (t->mm == current->mm)
+   ret = force_sig_mceerr(BUS_MCEERR_AR,
+(void __user *)tk->addr, addr_lsb);
+   /* send no signal to non-current processes */
} else {
/*
 * Don't use force here, it's convenient if the signal
-- 
2.14.3 (Apple Git-98)

[PATCH] mm, memory_failure: only send BUS_MCEERR_AO to early-kill process

[Wetp Zhang]

From: Zhang Yi 

If a process don't need early-kill, it may not care the BUS_MCEERR_AO.
Let the process to be killed when it really access the corrupted memory.

Signed-off-by: Zhang Yi 
---
 mm/memory-failure.c | 7 ---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index a96364be8ab4..2db13d48865c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -210,7 +210,7 @@ static int kill_proc(struct to_kill *tk, unsigned long pfn, 
int flags)
 {
struct task_struct *t = tk->tsk;
short addr_lsb = tk->size_shift;
-   int ret;
+   int ret = 0;
 
pr_err("Memory failure: %#lx: Sending SIGBUS to %s:%d due to hardware 
memory corruption\n",
pfn, t->comm, t->pid);
@@ -225,8 +225,9 @@ static int kill_proc(struct to_kill *tk, unsigned long pfn, 
int flags)
 * This could cause a loop when the user sets SIGBUS
 * to SIG_IGN, but hopefully no one will do that?
 */
-   ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)tk->addr,
- addr_lsb, t);  /* synchronous? */
+   if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY))
+   ret = send_sig_mceerr(BUS_MCEERR_AO,
+   (void __user *)tk->addr, addr_lsb, t);
}
if (ret < 0)
pr_info("Memory failure: Error sending signal to %s:%d: %d\n",
-- 
2.14.3 (Apple Git-98)