[packages/kernel] - rel 3; v2 version of the patch
arekm
arekm at pld-linux.org
Sat Jan 26 14:25:13 CET 2019
commit 18976fa6125612d8c13d643c4a1a0269ed29e2c5
Author: Arkadiusz Miśkiewicz <arekm at maven.pl>
Date: Sat Jan 26 14:24:12 2019 +0100
- rel 3; v2 version of the patch
kernel-small_fixes.patch | 180 ++++++++++++++++++-----------------------------
kernel.spec | 2 +-
2 files changed, 71 insertions(+), 111 deletions(-)
---
diff --git a/kernel.spec b/kernel.spec
index 166a18e1..16f7c40e 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -67,7 +67,7 @@
%define have_pcmcia 0
%endif
-%define rel 2
+%define rel 3
%define basever 4.20
%define postver .3
diff --git a/kernel-small_fixes.patch b/kernel-small_fixes.patch
index 19610274..c210e451 100644
--- a/kernel-small_fixes.patch
+++ b/kernel-small_fixes.patch
@@ -162,113 +162,73 @@ index 76c92e31afc0..abb5d382f64d 100644
--
cgit 1.2-0.3.lf.el7
-From 48744b6339cf649a69b55997e138c17df1ecc897 Mon Sep 17 00:00:00 2001
-From: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
-Date: Sat, 26 Jan 2019 20:00:51 +0900
-Subject: [PATCH] oom, oom_reaper: do not enqueue same task twice
-
-Arkadiusz reported that enabling memcg's group oom killing causes
-strange memcg statistics where there is no task in a memcg despite
-the number of tasks in that memcg is not 0. It turned out that there
-is a bug in wake_oom_reaper() which allows enqueuing same task twice
-which makes impossible to decrease the number of tasks in that memcg
-due to a refcount leak.
-
-This bug existed since the OOM reaper became invokable from
-task_will_free_mem(current) path in out_of_memory() in Linux 4.7,
-but memcg's group oom killing made it easier to trigger this bug by
-calling wake_oom_reaper() on the same task from one out_of_memory()
-request.
-
-Fix this bug using an approach used by commit 855b018325737f76
-("oom, oom_reaper: disable oom_reaper for oom_kill_allocating_task").
-Since task_will_free_mem(p) == false if p->mm == NULL, we can assume that
-p->mm != NULL when wake_oom_reaper() is called from task_will_free_mem()
-paths. As a side effect of this patch, this patch also avoids enqueuing
-multiple threads sharing memory via task_will_free_mem(current) path.
-
-Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
-Reported-by: Arkadiusz Miśkiewicz <a.miskiewicz at gmail.com>
-Fixes: af8e15cc85a25315 ("oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head")
----
- mm/oom_kill.c | 28 +++++++++++++---------------
- 1 file changed, 13 insertions(+), 15 deletions(-)
-
-diff --git a/mm/oom_kill.c b/mm/oom_kill.c
-index f0e8cd9..457f240 100644
---- a/mm/oom_kill.c
-+++ b/mm/oom_kill.c
-@@ -505,14 +505,6 @@ bool __oom_reap_task_mm(struct mm_struct *mm)
- struct vm_area_struct *vma;
- bool ret = true;
-
-- /*
-- * Tell all users of get_user/copy_from_user etc... that the content
-- * is no longer stable. No barriers really needed because unmapping
-- * should imply barriers already and the reader would hit a page fault
-- * if it stumbled over a reaped memory.
-- */
-- set_bit(MMF_UNSTABLE, &mm->flags);
--
- for (vma = mm->mmap ; vma; vma = vma->vm_next) {
- if (!can_madv_dontneed_vma(vma))
- continue;
-@@ -645,10 +637,15 @@ static int oom_reaper(void *unused)
- return 0;
- }
-
--static void wake_oom_reaper(struct task_struct *tsk)
-+static void wake_oom_reaper(struct task_struct *tsk, struct mm_struct *mm)
- {
-- /* tsk is already queued? */
-- if (tsk == oom_reaper_list || tsk->oom_reaper_list)
-+ /*
-+ * Tell all users of get_user/copy_from_user etc... that the content
-+ * is no longer stable. No barriers really needed because unmapping
-+ * should imply barriers already and the reader would hit a page fault
-+ * if it stumbled over a reaped memory.
-+ */
-+ if (test_and_set_bit(MMF_UNSTABLE, &mm->flags))
- return;
-
- get_task_struct(tsk);
-@@ -668,7 +665,8 @@ static int __init oom_init(void)
- }
- subsys_initcall(oom_init)
- #else
--static inline void wake_oom_reaper(struct task_struct *tsk)
-+static inline void wake_oom_reaper(struct task_struct *tsk,
-+ struct mm_struct *mm)
- {
- }
- #endif /* CONFIG_MMU */
-@@ -915,7 +913,7 @@ static void __oom_kill_process(struct task_struct *victim)
- rcu_read_unlock();
-
- if (can_oom_reap)
-- wake_oom_reaper(victim);
-+ wake_oom_reaper(victim, mm);
-
- mmdrop(mm);
- put_task_struct(victim);
-@@ -955,7 +953,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
- task_lock(p);
- if (task_will_free_mem(p)) {
- mark_oom_victim(p);
-- wake_oom_reaper(p);
-+ wake_oom_reaper(p, p->mm);
- task_unlock(p);
- put_task_struct(p);
- return;
-@@ -1085,7 +1083,7 @@ bool out_of_memory(struct oom_control *oc)
- */
- if (task_will_free_mem(current)) {
- mark_oom_victim(current);
-- wake_oom_reaper(current);
-+ wake_oom_reaper(current, current->mm);
- return true;
- }
-
---
-1.8.3.1
-
+
+From 9c9e935fc038342c48461aabca666f1b544e32b1 Mon Sep 17 00:00:00 2001
+From: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
+Date: Sat, 26 Jan 2019 21:57:25 +0900
+Subject: [PATCH v2] oom, oom_reaper: do not enqueue same task twice
+
+Arkadiusz reported that enabling memcg's group oom killing causes
+strange memcg statistics where there is no task in a memcg despite
+the number of tasks in that memcg is not 0. It turned out that there
+is a bug in wake_oom_reaper() which allows enqueuing same task twice
+which makes impossible to decrease the number of tasks in that memcg
+due to a refcount leak.
+
+This bug existed since the OOM reaper became invokable from
+task_will_free_mem(current) path in out_of_memory() in Linux 4.7,
+but memcg's group oom killing made it easier to trigger this bug by
+calling wake_oom_reaper() on the same task from one out_of_memory()
+request.
+
+Fix this bug using an approach used by commit 855b018325737f76
+("oom, oom_reaper: disable oom_reaper for oom_kill_allocating_task").
+As a side effect of this patch, this patch also avoids enqueuing
+multiple threads sharing memory via task_will_free_mem(current) path.
+
+Signed-off-by: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
+Reported-by: Arkadiusz Miśkiewicz <arekm at maven.pl>
+Tested-by: Arkadiusz Miśkiewicz <arekm at maven.pl>
+Fixes: af8e15cc85a25315 ("oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head")
+---
+ mm/oom_kill.c | 17 +++++++----------
+ 1 file changed, 7 insertions(+), 10 deletions(-)
+
+diff --git a/mm/oom_kill.c b/mm/oom_kill.c
+index f0e8cd9..057bfee 100644
+--- a/mm/oom_kill.c
++++ b/mm/oom_kill.c
+@@ -505,14 +505,6 @@ bool __oom_reap_task_mm(struct mm_struct *mm)
+ struct vm_area_struct *vma;
+ bool ret = true;
+
+- /*
+- * Tell all users of get_user/copy_from_user etc... that the content
+- * is no longer stable. No barriers really needed because unmapping
+- * should imply barriers already and the reader would hit a page fault
+- * if it stumbled over a reaped memory.
+- */
+- set_bit(MMF_UNSTABLE, &mm->flags);
+-
+ for (vma = mm->mmap ; vma; vma = vma->vm_next) {
+ if (!can_madv_dontneed_vma(vma))
+ continue;
+@@ -647,8 +639,13 @@ static int oom_reaper(void *unused)
+
+ static void wake_oom_reaper(struct task_struct *tsk)
+ {
+- /* tsk is already queued? */
+- if (tsk == oom_reaper_list || tsk->oom_reaper_list)
++ /*
++ * Tell all users of get_user/copy_from_user etc... that the content
++ * is no longer stable. No barriers really needed because unmapping
++ * should imply barriers already and the reader would hit a page fault
++ * if it stumbled over a reaped memory.
++ */
++ if (test_and_set_bit(MMF_UNSTABLE, &tsk->signal->oom_mm->flags))
+ return;
+
+ get_task_struct(tsk);
+--
+1.8.3.1
+
================================================================
---- gitweb:
http://git.pld-linux.org/gitweb.cgi/packages/kernel.git/commitdiff/18976fa6125612d8c13d643c4a1a0269ed29e2c5
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