* [PATCH] mm: add warning if __vm_enough_memory fails
@ 2022-07-26 7:24 Kefeng Wang
2022-07-26 13:45 ` David Hildenbrand
0 siblings, 1 reply; 3+ messages in thread
From: Kefeng Wang @ 2022-07-26 7:24 UTC (permalink / raw)
To: Andrew Morton, linux-mm, linux-kernel; +Cc: Kefeng Wang, Yongqiang Liu
If a process has no enough memory to allocate a new virtual mapping, we
may meet kinds of error, eg, fork cannot allocate memory, SIGBUS error
in shmem, but it is difficult to confirm them, let's add some debug
information to easy to check this scenario if __vm_enough_memory fails.
Reported-by: Yongqiang Liu <liuyongqiang13@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
mm/util.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/util.c b/mm/util.c
index 1266a33a49ea..19bfff8a0ad6 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -1020,6 +1020,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
if (percpu_counter_read_positive(&vm_committed_as) < allowed)
return 0;
error:
+ pr_warn("%s: pid: %d, comm: %s, no enough memory for the allocation\n",
+ __func__, current->pid, current->comm);
vm_unacct_memory(pages);
return -ENOMEM;
--
2.35.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] mm: add warning if __vm_enough_memory fails
2022-07-26 7:24 [PATCH] mm: add warning if __vm_enough_memory fails Kefeng Wang
@ 2022-07-26 13:45 ` David Hildenbrand
2022-07-26 14:42 ` Kefeng Wang
0 siblings, 1 reply; 3+ messages in thread
From: David Hildenbrand @ 2022-07-26 13:45 UTC (permalink / raw)
To: Kefeng Wang, Andrew Morton, linux-mm, linux-kernel; +Cc: Yongqiang Liu
On 26.07.22 09:24, Kefeng Wang wrote:
> If a process has no enough memory to allocate a new virtual mapping, we
> may meet kinds of error, eg, fork cannot allocate memory, SIGBUS error
> in shmem, but it is difficult to confirm them, let's add some debug
> information to easy to check this scenario if __vm_enough_memory fails.
>
> Reported-by: Yongqiang Liu <liuyongqiang13@huawei.com>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
> ---
> mm/util.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/mm/util.c b/mm/util.c
> index 1266a33a49ea..19bfff8a0ad6 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -1020,6 +1020,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
> if (percpu_counter_read_positive(&vm_committed_as) < allowed)
> return 0;
> error:
> + pr_warn("%s: pid: %d, comm: %s, no enough memory for the allocation\n",
> + __func__, current->pid, current->comm);
> vm_unacct_memory(pages);
>
> return -ENOMEM;
Users can easily spam the kernel log, no? Maybe at least ratelimit.
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mm: add warning if __vm_enough_memory fails
2022-07-26 13:45 ` David Hildenbrand
@ 2022-07-26 14:42 ` Kefeng Wang
0 siblings, 0 replies; 3+ messages in thread
From: Kefeng Wang @ 2022-07-26 14:42 UTC (permalink / raw)
To: David Hildenbrand, Andrew Morton, linux-mm, linux-kernel; +Cc: Yongqiang Liu
On 2022/7/26 21:45, David Hildenbrand wrote:
> On 26.07.22 09:24, Kefeng Wang wrote:
>> If a process has no enough memory to allocate a new virtual mapping, we
>> may meet kinds of error, eg, fork cannot allocate memory, SIGBUS error
>> in shmem, but it is difficult to confirm them, let's add some debug
>> information to easy to check this scenario if __vm_enough_memory fails.
>>
>> Reported-by: Yongqiang Liu <liuyongqiang13@huawei.com>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
>> ---
>> mm/util.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/mm/util.c b/mm/util.c
>> index 1266a33a49ea..19bfff8a0ad6 100644
>> --- a/mm/util.c
>> +++ b/mm/util.c
>> @@ -1020,6 +1020,8 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
>> if (percpu_counter_read_positive(&vm_committed_as) < allowed)
>> return 0;
>> error:
>> + pr_warn("%s: pid: %d, comm: %s, no enough memory for the allocation\n",
>> + __func__, current->pid, current->comm);
>> vm_unacct_memory(pages);
>>
>> return -ENOMEM;
> Users can easily spam the kernel log, no? Maybe at least ratelimit.
pr_warn_ratelimited is better, will update, thanks.
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-07-26 13:45 ` David Hildenbrand
2022-07-26 14:42 ` Kefeng Wang
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