The patch titled
memrlimit: improve error handling
has been added to the -mm tree. Its filename is
memrlimit-improve-error-handling.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memrlimit: improve error handling
From: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
memrlimit cgroup does not handle error cases after may_expand_vm(). This
BUG was reported by Kamezawa, with the test case below to reproduce it
[root@iridium kamezawa]# cat /opt/cgroup/test/memrlimit.usage_in_bytes
71921664
[root@iridium kamezawa]# ulimit -s 3
[root@iridium kamezawa]# ls
Killed
[root@iridium kamezawa]# ls
Killed
[root@iridium kamezawa]# ls
Killed
[root@iridium kamezawa]# ls
Killed
[root@iridium kamezawa]# ls
Killed
[root@iridium kamezawa]# ulimit -s unlimited
[root@iridium kamezawa]# cat /opt/cgroup/test/memrlimit.usage_in_bytes
72368128
[root@iridium kamezawa]#
This patch adds better handling support to fix the reported problem.
Reported-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Sudhir Kumar <skumar@xxxxxxxxxxxxxxxxxx>
Cc: YAMAMOTO Takashi <yamamoto@xxxxxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 36 +++++++++++++++++++++++++-----------
mm/mremap.c | 6 ++++++
2 files changed, 31 insertions(+), 11 deletions(-)
diff -puN mm/mmap.c~memrlimit-improve-error-handling mm/mmap.c
--- a/mm/mmap.c~memrlimit-improve-error-handling
+++ a/mm/mmap.c
@@ -1124,7 +1124,7 @@ munmap_back:
*/
charged = len >> PAGE_SHIFT;
if (security_vm_enough_memory(charged))
- return -ENOMEM;
+ goto undo_charge;
vm_flags |= VM_ACCOUNT;
}
}
@@ -1240,6 +1240,8 @@ free_vma:
unacct_error:
if (charged)
vm_unacct_memory(charged);
+undo_charge:
+ memrlimit_cgroup_uncharge_as(mm, len >> PAGE_SHIFT);
return error;
}
@@ -1535,14 +1537,15 @@ static int acct_stack_growth(struct vm_a
struct mm_struct *mm = vma->vm_mm;
struct rlimit *rlim = current->signal->rlim;
unsigned long new_start;
+ int ret = -ENOMEM;
/* address space limit tests */
if (!may_expand_vm(mm, grow))
- return -ENOMEM;
+ goto out;
/* Stack limit test */
if (size > rlim[RLIMIT_STACK].rlim_cur)
- return -ENOMEM;
+ goto undo_charge;
/* mlock limit tests */
if (vma->vm_flags & VM_LOCKED) {
@@ -1551,21 +1554,23 @@ static int acct_stack_growth(struct vm_a
locked = mm->locked_vm + grow;
limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
if (locked > limit && !capable(CAP_IPC_LOCK))
- return -ENOMEM;
+ goto undo_charge;
}
/* Check to ensure the stack will not grow into a hugetlb-only region */
new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
vma->vm_end - size;
- if (is_hugepage_only_range(vma->vm_mm, new_start, size))
- return -EFAULT;
+ if (is_hugepage_only_range(vma->vm_mm, new_start, size)) {
+ ret = -EFAULT;
+ goto undo_charge;
+ }
/*
* Overcommit.. This must be the final test, as it will
* update security statistics.
*/
if (security_vm_enough_memory(grow))
- return -ENOMEM;
+ goto undo_charge;
/* Ok, everything looks good - let it rip */
mm->total_vm += grow;
@@ -1573,6 +1578,11 @@ static int acct_stack_growth(struct vm_a
mm->locked_vm += grow;
vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
return 0;
+undo_charge:
+ /* Undo memrlimit charge */
+ memrlimit_cgroup_uncharge_as(mm, grow);
+out:
+ return ret;
}
#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
@@ -1959,6 +1969,7 @@ unsigned long do_brk(unsigned long addr,
struct rb_node ** rb_link, * rb_parent;
pgoff_t pgoff = addr >> PAGE_SHIFT;
int error;
+ int ret = -ENOMEM;
len = PAGE_ALIGN(len);
if (!len)
@@ -2012,13 +2023,13 @@ unsigned long do_brk(unsigned long addr,
/* Check against address space limits *after* clearing old maps... */
if (!may_expand_vm(mm, len >> PAGE_SHIFT))
- return -ENOMEM;
+ return ret;
if (mm->map_count > sysctl_max_map_count)
- return -ENOMEM;
+ goto undo_charge;
if (security_vm_enough_memory(len >> PAGE_SHIFT))
- return -ENOMEM;
+ goto undo_charge;
/* Can we just expand an old private anonymous mapping? */
if (vma_merge(mm, prev, addr, addr + len, flags,
@@ -2031,7 +2042,7 @@ unsigned long do_brk(unsigned long addr,
vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
if (!vma) {
vm_unacct_memory(len >> PAGE_SHIFT);
- return -ENOMEM;
+ goto undo_charge;
}
vma->vm_mm = mm;
@@ -2048,6 +2059,9 @@ out:
make_pages_present(addr, addr + len);
}
return addr;
+undo_charge:
+ memrlimit_cgroup_uncharge_as(mm, len >> PAGE_SHIFT);
+ return ret;
}
EXPORT_SYMBOL(do_brk);
diff -puN mm/mremap.c~memrlimit-improve-error-handling mm/mremap.c
--- a/mm/mremap.c~memrlimit-improve-error-handling
+++ a/mm/mremap.c
@@ -18,6 +18,7 @@
#include <linux/highmem.h>
#include <linux/security.h>
#include <linux/syscalls.h>
+#include <linux/memrlimitcgroup.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
@@ -254,6 +255,7 @@ unsigned long do_mremap(unsigned long ad
struct vm_area_struct *vma;
unsigned long ret = -EINVAL;
unsigned long charged = 0;
+ int vm_expanded = 0;
if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
goto out;
@@ -347,6 +349,7 @@ unsigned long do_mremap(unsigned long ad
goto out;
}
+ vm_expanded = 1;
if (vma->vm_flags & VM_ACCOUNT) {
charged = (new_len - old_len) >> PAGE_SHIFT;
if (security_vm_enough_memory(charged))
@@ -409,6 +412,9 @@ out:
if (ret & ~PAGE_MASK)
vm_unacct_memory(charged);
out_nc:
+ if (vm_expanded)
+ memrlimit_cgroup_uncharge_as(mm,
+ (new_len - old_len) >> PAGE_SHIFT);
return ret;
}
_
Patches currently in -mm which might be from balbir@xxxxxxxxxxxxxxxxxx are
cgroup-use-read-lock-to-guard-find_existing_css_set.patch
mark-res_counter_charge_locked-with-__must_check.patch
memcg-make-global-var-read_mostly.patch
memcg-avoid-unnecessary-initialization.patch
memcg-remove-refcnt-from-page_cgroup-fix-memcg-fix-mem_cgroup_end_migration-race.patch
memcg-clean-up-checking-of-the-disabled-flag.patch
memrlimit-add-memrlimit-controller-documentation.patch
memrlimit-setup-the-memrlimit-controller.patch
memrlimit-cgroup-mm-owner-callback-changes-to-add-task-info.patch
memrlimit-add-memrlimit-controller-accounting-and-control.patch
memrlimit-add-memrlimit-controller-accounting-and-control-fix.patch
memrlimit-improve-error-handling.patch
memrlimit-handle-attach_task-failure-add-can_attach-callback.patch
distinct-tgid-tid-i-o-statistics.patch
per-task-delay-accounting-add-memory-reclaim-delay.patch
per-task-delay-accounting-update-document-and-getdelaysc-for-memory-reclaim.patch
memrlimit-fix-usage-of-tmp-as-a-parameter-name.patch
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