The patch titled
Subject: memcg: close the race between migration and installing bprm->mm as mm
has been added to the -mm tree. Its filename is
memcg-replace-mm-owner-with-mm-memcg-fix-2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/memcg-replace-mm-owner-with-mm-memcg-fix-2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/memcg-replace-mm-owner-with-mm-memcg-fix-2.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Subject: memcg: close the race between migration and installing bprm->mm as mm
Oleg pointed out that there is a race at exec time between when bprm->mm
is initialized and the exec'ing task being migrated to a different memory
control group.
Ractor the code in memcontrol so exec_mmap can use the same code as as
fork to ensure that task->memcg == task->mm->memcg.
Link: http://lkml.kernel.org/r/87fu37cow4.fsf_-_@xxxxxxxxxxxx
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Reported-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/exec.c | 2 ++
include/linux/memcontrol.h | 5 +++++
mm/memcontrol.c | 4 ++--
3 files changed, 9 insertions(+), 2 deletions(-)
diff -puN fs/exec.c~memcg-replace-mm-owner-with-mm-memcg-fix-2 fs/exec.c
--- a/fs/exec.c~memcg-replace-mm-owner-with-mm-memcg-fix-2
+++ a/fs/exec.c
@@ -1044,6 +1044,8 @@ static int exec_mmap(struct mm_struct *m
return 0;
}
mmdrop(active_mm);
+ /* The tsk may have migrated before the new mm was attached */
+ mm_sync_memcg_from_task(tsk);
return 0;
}
diff -puN include/linux/memcontrol.h~memcg-replace-mm-owner-with-mm-memcg-fix-2 include/linux/memcontrol.h
--- a/include/linux/memcontrol.h~memcg-replace-mm-owner-with-mm-memcg-fix-2
+++ a/include/linux/memcontrol.h
@@ -408,6 +408,7 @@ static inline bool mem_cgroup_is_descend
}
void mm_update_memcg(struct mm_struct *mm, struct mem_cgroup *new);
+void mm_sync_memcg_from_task(struct task_struct *tsk);
static inline bool mm_match_cgroup(struct mm_struct *mm,
struct mem_cgroup *memcg)
@@ -792,6 +793,10 @@ static inline void mm_update_memcg(struc
{
}
+static inline void mm_sync_memcg_from_task(struct task_struct *tsk)
+{
+}
+
static inline bool mm_match_cgroup(struct mm_struct *mm,
struct mem_cgroup *memcg)
{
diff -puN mm/memcontrol.c~memcg-replace-mm-owner-with-mm-memcg-fix-2 mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-replace-mm-owner-with-mm-memcg-fix-2
+++ a/mm/memcontrol.c
@@ -5079,7 +5079,7 @@ static void mem_cgroup_attach(struct cgr
}
}
-static void mem_cgroup_fork(struct task_struct *tsk)
+void mm_sync_memcg_from_task(struct task_struct *tsk)
{
struct cgroup_subsys_state *css;
@@ -5393,7 +5393,7 @@ struct cgroup_subsys memory_cgrp_subsys
.attach = mem_cgroup_attach,
.cancel_attach = mem_cgroup_cancel_attach,
.post_attach = mem_cgroup_move_task,
- .fork = mem_cgroup_fork,
+ .fork = mm_sync_memcg_from_task,
.bind = mem_cgroup_bind,
.dfl_cftypes = memory_files,
.legacy_cftypes = mem_cgroup_legacy_files,
_
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
memcg-replace-mm-owner-with-mm-memcg.patch
memcg-replace-mm-owner-with-mm-memcg-fix.patch
memcg-replace-mm-owner-with-mm-memcg-fix-2.patch
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