The patch titled
Subject: mm/memory-failure: prioritize prctl(PR_MCE_KILL) over vm.memory_failure_early_kill
has been added to the -mm tree. Its filename is
mm-memory-failure-prioritize-prctlpr_mce_kill-over-vmmemory_failure_early_kill.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory-failure-prioritize-prctlpr_mce_kill-over-vmmemory_failure_early_kill.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory-failure-prioritize-prctlpr_mce_kill-over-vmmemory_failure_early_kill.patch
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------------------------------------------------------
From: Naoya Horiguchi <nao.horiguchi@xxxxxxxxx>
Subject: mm/memory-failure: prioritize prctl(PR_MCE_KILL) over vm.memory_failure_early_kill
Patch series "hwpoison: fixes signaling on memory error"
This is a small patchset to solve issues in memory error handler to
send SIGBUS to proper process/thread as expected in configuration.
Please see descriptions in individual patches for more details.
This patch (of 2):
Early-kill policy is controlled from two types of settings, one is
per-process setting prctl(PR_MCE_KILL) and the other is system-wide
setting vm.memory_failure_early_kill. Users expect per-process setting to
override system-wide setting as many other settings do, but early-kill
setting doesn't work as such. For example, if a system configures
vm.memory_failure_early_kill to 1 (enabled), a process receives SIGBUS
even if it's configured to explicitly disable PF_MCE_KILL by prctl().
That's not desirable for applications with their own policies.
This patch is suggesting to change the priority of these two types of
settings, by checking sysctl_memory_failure_early_kill only when a given
process has the default kill policy.
Note that this patch is solving a thread choice issue too. Originally,
collect_procs() always chooses the main thread when
vm.memory_failure_early_kill is 1, even if the process has a dedicated
thread for memory error handling. SIGBUS should be sent to the dedicated
thread if early-kill is enabled via vm.memory_failure_early_kill as we are
doing for PR_MCE_KILL_EARLY processes.
Link: http://lkml.kernel.org/r/1591321039-22141-1-git-send-email-naoya.horiguchi@xxxxxxx
Link: http://lkml.kernel.org/r/1591321039-22141-2-git-send-email-naoya.horiguchi@xxxxxxx
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
--- a/mm/memory-failure.c~mm-memory-failure-prioritize-prctlpr_mce_kill-over-vmmemory_failure_early_kill
+++ a/mm/memory-failure.c
@@ -402,9 +402,15 @@ static struct task_struct *find_early_ki
{
struct task_struct *t;
- for_each_thread(tsk, t)
- if ((t->flags & PF_MCE_PROCESS) && (t->flags & PF_MCE_EARLY))
- return t;
+ for_each_thread(tsk, t) {
+ if (t->flags & PF_MCE_PROCESS) {
+ if (t->flags & PF_MCE_EARLY)
+ return t;
+ } else {
+ if (sysctl_memory_failure_early_kill)
+ return t;
+ }
+ }
return NULL;
}
@@ -417,17 +423,11 @@ static struct task_struct *find_early_ki
static struct task_struct *task_early_kill(struct task_struct *tsk,
int force_early)
{
- struct task_struct *t;
if (!tsk->mm)
return NULL;
if (force_early)
return tsk;
- t = find_early_kill_thread(tsk);
- if (t)
- return t;
- if (sysctl_memory_failure_early_kill)
- return tsk;
- return NULL;
+ return find_early_kill_thread(tsk);
}
/*
_
Patches currently in -mm which might be from nao.horiguchi@xxxxxxxxx are
mm-memory-failure-prioritize-prctlpr_mce_kill-over-vmmemory_failure_early_kill.patch
mm-memory-failure-send-sigbusbus_mceerr_ar-only-to-current-thread.patch
