* [PATCH] mm/shmem.c: Fix the missing unaccount on the failed path
@ 2020-09-20 16:30 Tianjia Zhang
2020-09-20 18:49 ` Hugh Dickins
0 siblings, 1 reply; 3+ messages in thread
From: Tianjia Zhang @ 2020-09-20 16:30 UTC (permalink / raw)
To: Hugh Dickins, Andrew Morton, Al Viro, linux-mm, linux-kernel
Cc: Tianjia Zhang
In function __shmem_file_setup(), shmem_unacct_size() is forgotten
on the failed path, so add it.
Fixes: 93dec2da7b234 ("... and switch shmem_file_setup() to alloc_file_pseudo()")
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
---
mm/shmem.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 8e2b35ba93ad..591410dc3541 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4200,8 +4200,10 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
if (!IS_ERR(res))
res = alloc_file_pseudo(inode, mnt, name, O_RDWR,
&shmem_file_operations);
- if (IS_ERR(res))
+ if (IS_ERR(res)) {
iput(inode);
+ shmem_unacct_size(flags, size);
+ }
return res;
}
--
2.19.1.3.ge56e4f7
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] mm/shmem.c: Fix the missing unaccount on the failed path
2020-09-20 16:30 [PATCH] mm/shmem.c: Fix the missing unaccount on the failed path Tianjia Zhang
@ 2020-09-20 18:49 ` Hugh Dickins
2020-09-22 5:27 ` Tianjia Zhang
0 siblings, 1 reply; 3+ messages in thread
From: Hugh Dickins @ 2020-09-20 18:49 UTC (permalink / raw)
To: Tianjia Zhang
Cc: Hugh Dickins, Andrew Morton, Al Viro, linux-mm, linux-kernel
On Mon, 21 Sep 2020, Tianjia Zhang wrote:
> In function __shmem_file_setup(), shmem_unacct_size() is forgotten
> on the failed path, so add it.
>
> Fixes: 93dec2da7b234 ("... and switch shmem_file_setup() to alloc_file_pseudo()")
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
> ---
> mm/shmem.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 8e2b35ba93ad..591410dc3541 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -4200,8 +4200,10 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
> if (!IS_ERR(res))
> res = alloc_file_pseudo(inode, mnt, name, O_RDWR,
> &shmem_file_operations);
> - if (IS_ERR(res))
> + if (IS_ERR(res)) {
> iput(inode);
> + shmem_unacct_size(flags, size);
> + }
> return res;
> }
>
> --
> 2.19.1.3.ge56e4f7
Looks mistaken to me.
Is this something you noticed by source inspection,
or something you have observed in practice?
I haven't tried exercising this path while injecting errors into
alloc_file_pseudo(); but what I'd expect to happen is that the
iput(inode), which you see already on that error path, will get
to evict the inode, which will entail calling shmem_evict_inode(),
which does that shmem_unacct_size() itself.
Hugh
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] mm/shmem.c: Fix the missing unaccount on the failed path
2020-09-20 18:49 ` Hugh Dickins
@ 2020-09-22 5:27 ` Tianjia Zhang
0 siblings, 0 replies; 3+ messages in thread
From: Tianjia Zhang @ 2020-09-22 5:27 UTC (permalink / raw)
To: Hugh Dickins; +Cc: Andrew Morton, Al Viro, linux-mm, linux-kernel
On 9/21/20 2:49 AM, Hugh Dickins wrote:
> On Mon, 21 Sep 2020, Tianjia Zhang wrote:
>
>> In function __shmem_file_setup(), shmem_unacct_size() is forgotten
>> on the failed path, so add it.
>>
>> Fixes: 93dec2da7b234 ("... and switch shmem_file_setup() to alloc_file_pseudo()")
>> Cc: Al Viro <viro@zeniv.linux.org.uk>
>> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
>> ---
>> mm/shmem.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/shmem.c b/mm/shmem.c
>> index 8e2b35ba93ad..591410dc3541 100644
>> --- a/mm/shmem.c
>> +++ b/mm/shmem.c
>> @@ -4200,8 +4200,10 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l
>> if (!IS_ERR(res))
>> res = alloc_file_pseudo(inode, mnt, name, O_RDWR,
>> &shmem_file_operations);
>> - if (IS_ERR(res))
>> + if (IS_ERR(res)) {
>> iput(inode);
>> + shmem_unacct_size(flags, size);
>> + }
>> return res;
>> }
>>
>> --
>> 2.19.1.3.ge56e4f7
>
> Looks mistaken to me.
>
> Is this something you noticed by source inspection,
> or something you have observed in practice?
>
> I haven't tried exercising this path while injecting errors into
> alloc_file_pseudo(); but what I'd expect to happen is that the
> iput(inode), which you see already on that error path, will get
> to evict the inode, which will entail calling shmem_evict_inode(),
> which does that shmem_unacct_size() itself.
>
> Hugh
>
I noticed by looking at the code. you are right, I neglected this point,
thanks for your explanation.
Thanks,
Tianjia
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-09-22 5:27 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-20 16:30 [PATCH] mm/shmem.c: Fix the missing unaccount on the failed path Tianjia Zhang
2020-09-20 18:49 ` Hugh Dickins
2020-09-22 5:27 ` Tianjia Zhang
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox