* [PATCH v2 0/3] a few cleanup and bugfixes about shmem
@ 2022-06-05 3:55 Chen Wandun
2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Chen Wandun @ 2022-06-05 3:55 UTC (permalink / raw)
To: hughd, akpm, linux-mm, linux-kernel, willy, david, wangkefeng.wang
v1 ==> v2:
combine patch2 and patch3 into a single patch.
Chen Wandun (3):
mm/shmem: check return value of shmem_init_inodecache
mm/shmem: return error code directly for invalid addr
mm/shmem: rework calculation of inflated_addr in
shmem_get_unmapped_area
mm/shmem.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
--
2.25.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache
2022-06-05 3:55 [PATCH v2 0/3] a few cleanup and bugfixes about shmem Chen Wandun
@ 2022-06-05 3:55 ` Chen Wandun
2022-06-05 11:49 ` Matthew Wilcox
2022-06-05 3:55 ` [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr Chen Wandun
2022-06-05 3:55 ` [PATCH v2 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area Chen Wandun
2 siblings, 1 reply; 8+ messages in thread
From: Chen Wandun @ 2022-06-05 3:55 UTC (permalink / raw)
To: hughd, akpm, linux-mm, linux-kernel, willy, david, wangkefeng.wang
It will result in null pointer access if shmem_init_inodecache fail,
so check return value of shmem_init_inodecache
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
---
mm/shmem.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 12d45a03f7fc..17f8297ece29 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3775,11 +3775,13 @@ static void shmem_init_inode(void *foo)
inode_init_once(&info->vfs_inode);
}
-static void shmem_init_inodecache(void)
+static struct kmem_cache *shmem_init_inodecache(void)
{
shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
sizeof(struct shmem_inode_info),
0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
+
+ return shmem_inode_cachep;
}
static void shmem_destroy_inodecache(void)
@@ -3923,7 +3925,10 @@ void __init shmem_init(void)
{
int error;
- shmem_init_inodecache();
+ if (!shmem_init_inodecache()) {
+ error = -ENOMEM;
+ goto out2;
+ }
error = register_filesystem(&shmem_fs_type);
if (error) {
--
2.25.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr
2022-06-05 3:55 [PATCH v2 0/3] a few cleanup and bugfixes about shmem Chen Wandun
2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun
@ 2022-06-05 3:55 ` Chen Wandun
2022-06-05 3:55 ` [PATCH v2 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area Chen Wandun
2 siblings, 0 replies; 8+ messages in thread
From: Chen Wandun @ 2022-06-05 3:55 UTC (permalink / raw)
To: hughd, akpm, linux-mm, linux-kernel, willy, david, wangkefeng.wang
Return error code directly for addr is not PAGE_SIZE aligned or
beyond TASK_SIZE, no need to check these cases in caller.
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
---
mm/shmem.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 17f8297ece29..5e61692f2d8e 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2142,10 +2142,10 @@ unsigned long shmem_get_unmapped_area(struct file *file,
return addr;
if (IS_ERR_VALUE(addr))
return addr;
- if (addr & ~PAGE_MASK)
- return addr;
+ if (offset_in_page(addr))
+ return -EINVAL;
if (addr > TASK_SIZE - len)
- return addr;
+ return -ENOMEM;
if (shmem_huge == SHMEM_HUGE_DENY)
return addr;
@@ -2196,7 +2196,7 @@ unsigned long shmem_get_unmapped_area(struct file *file,
inflated_addr = get_area(NULL, uaddr, inflated_len, 0, flags);
if (IS_ERR_VALUE(inflated_addr))
return addr;
- if (inflated_addr & ~PAGE_MASK)
+ if (offset_in_page(inflated_addr))
return addr;
inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
--
2.25.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area
2022-06-05 3:55 [PATCH v2 0/3] a few cleanup and bugfixes about shmem Chen Wandun
2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun
2022-06-05 3:55 ` [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr Chen Wandun
@ 2022-06-05 3:55 ` Chen Wandun
2 siblings, 0 replies; 8+ messages in thread
From: Chen Wandun @ 2022-06-05 3:55 UTC (permalink / raw)
To: hughd, akpm, linux-mm, linux-kernel, willy, david, wangkefeng.wang
In function shmem_get_unmapped_area, inflated_offset and offset
are unsigned long, it will result in underflow when offset below
inflated_offset, a little confusing, no functional change.
Signed-off-by: Chen Wandun <chenwandun@huawei.com>
---
mm/shmem.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index 5e61692f2d8e..0b6c61a7cbb3 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2200,9 +2200,12 @@ unsigned long shmem_get_unmapped_area(struct file *file,
return addr;
inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
- inflated_addr += offset - inflated_offset;
- if (inflated_offset > offset)
+ if (offset > inflated_offset)
+ inflated_addr += offset - inflated_offset;
+ else if (offset < inflated_offset) {
+ inflated_addr -= inflated_offset - offset;
inflated_addr += HPAGE_PMD_SIZE;
+ }
if (inflated_addr > TASK_SIZE - len)
return addr;
--
2.25.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache
2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun
@ 2022-06-05 11:49 ` Matthew Wilcox
2022-06-06 1:34 ` Chen Wandun
0 siblings, 1 reply; 8+ messages in thread
From: Matthew Wilcox @ 2022-06-05 11:49 UTC (permalink / raw)
To: Chen Wandun; +Cc: hughd, akpm, linux-mm, linux-kernel, david, wangkefeng.wang
On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote:
> It will result in null pointer access if shmem_init_inodecache fail,
> so check return value of shmem_init_inodecache
You ignored my suggestion from v1. Here, let me write it out for you.
+static int shmem_init_inodecache(void)
{
shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
sizeof(struct shmem_inode_info),
0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
+ if (!shmem_inode_cachep)
+ return -ENOMEM;
+ return 0;
}
...
+ error = shmem_init_inodecache();
+ if (error)
+ goto out2;
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache
2022-06-05 11:49 ` Matthew Wilcox
@ 2022-06-06 1:34 ` Chen Wandun
2022-06-06 2:08 ` Matthew Wilcox
0 siblings, 1 reply; 8+ messages in thread
From: Chen Wandun @ 2022-06-06 1:34 UTC (permalink / raw)
To: Matthew Wilcox
Cc: hughd, akpm, linux-mm, linux-kernel, david, wangkefeng.wang
On 2022/6/5 19:49, Matthew Wilcox wrote:
> On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote:
>> It will result in null pointer access if shmem_init_inodecache fail,
>> so check return value of shmem_init_inodecache
> You ignored my suggestion from v1. Here, let me write it out for you.
Hi Matthew,
I didn't ignore your suggestion, some explanation is needed, sorry for
that.
In V1, Kefeng point:
"kmem_cache_create return a pointer to the cache on success, NULL on
failure,
so error = -ENOMEM; is right :)"
so, I look some similar code such as init_inodecache in kinds of file
system, they all
return -ENOMEM on failure, so is it OK to return -ENOMEM on failure :)
Besides, kmem_cache_create return NULL on failure, maybe returning
error code
on failure is more proper, but it is another job.
>
> +static int shmem_init_inodecache(void)
> {
> shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
> sizeof(struct shmem_inode_info),
> 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
> + if (!shmem_inode_cachep)
> + return -ENOMEM;
> + return 0;
> }
>
> ...
>
> + error = shmem_init_inodecache();
> + if (error)
> + goto out2;
>
>
> .
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache
2022-06-06 1:34 ` Chen Wandun
@ 2022-06-06 2:08 ` Matthew Wilcox
2022-06-06 2:58 ` Chen Wandun
0 siblings, 1 reply; 8+ messages in thread
From: Matthew Wilcox @ 2022-06-06 2:08 UTC (permalink / raw)
To: Chen Wandun; +Cc: hughd, akpm, linux-mm, linux-kernel, david, wangkefeng.wang
On Mon, Jun 06, 2022 at 09:34:13AM +0800, Chen Wandun wrote:
> On 2022/6/5 19:49, Matthew Wilcox wrote:
> > On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote:
> > > It will result in null pointer access if shmem_init_inodecache fail,
> > > so check return value of shmem_init_inodecache
> > You ignored my suggestion from v1. Here, let me write it out for you.
> Hi Matthew,
> I didn't ignore your suggestion, some explanation is needed, sorry for
> that.
>
> In V1, Kefeng point:
> "kmem_cache_create return a pointer to the cache on success, NULL on
> failure,
> so error = -ENOMEM; is right :)"
>
> so, I look some similar code such as init_inodecache in kinds of file
> system, they all
> return -ENOMEM on failure, so is it OK to return -ENOMEM on failure :)
>
> Besides, kmem_cache_create return NULL on failure, maybe returning error
> code
> on failure is more proper, but it is another job.
I literally wrote out what I think you should do instead. Stop arguing.
> > +static int shmem_init_inodecache(void)
> > {
> > shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
> > sizeof(struct shmem_inode_info),
> > 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
> > + if (!shmem_inode_cachep)
> > + return -ENOMEM;
> > + return 0;
> > }
> >
> > ...
> >
> > + error = shmem_init_inodecache();
> > + if (error)
> > + goto out2;
> >
> >
> > .
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache
2022-06-06 2:08 ` Matthew Wilcox
@ 2022-06-06 2:58 ` Chen Wandun
0 siblings, 0 replies; 8+ messages in thread
From: Chen Wandun @ 2022-06-06 2:58 UTC (permalink / raw)
To: Matthew Wilcox
Cc: hughd, akpm, linux-mm, linux-kernel, david, wangkefeng.wang
在 2022/6/6 10:08, Matthew Wilcox 写道:
> On Mon, Jun 06, 2022 at 09:34:13AM +0800, Chen Wandun wrote:
>> On 2022/6/5 19:49, Matthew Wilcox wrote:
>>> On Sun, Jun 05, 2022 at 11:55:55AM +0800, Chen Wandun wrote:
>>>> It will result in null pointer access if shmem_init_inodecache fail,
>>>> so check return value of shmem_init_inodecache
>>> You ignored my suggestion from v1. Here, let me write it out for you.
>> Hi Matthew,
>> I didn't ignore your suggestion, some explanation is needed, sorry for
>> that.
>>
>> In V1, Kefeng point:
>> "kmem_cache_create return a pointer to the cache on success, NULL on
>> failure,
>> so error = -ENOMEM; is right :)"
>>
>> so, I look some similar code such as init_inodecache in kinds of file
>> system, they all
>> return -ENOMEM on failure, so is it OK to return -ENOMEM on failure :)
>>
>> Besides, kmem_cache_create return NULL on failure, maybe returning error
>> code
>> on failure is more proper, but it is another job.
> I literally wrote out what I think you should do instead. Stop arguing.
>
>>> +static int shmem_init_inodecache(void)
>>> {
>>> shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
>>> sizeof(struct shmem_inode_info),
>>> 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
>>> + if (!shmem_inode_cachep)
>>> + return -ENOMEM;
>>> + return 0;
>>> }
>>>
>>> ...
>>>
>>> + error = shmem_init_inodecache();
>>> + if (error)
>>> + goto out2;
Oh, I misunderstood what you said, feel so sorry.
I will send a new version.
Thanks.
>>>
>>>
>>> .
> .
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-06-06 2:59 UTC | newest]
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2022-06-05 3:55 [PATCH v2 0/3] a few cleanup and bugfixes about shmem Chen Wandun
2022-06-05 3:55 ` [PATCH v2 1/3] mm/shmem: check return value of shmem_init_inodecache Chen Wandun
2022-06-05 11:49 ` Matthew Wilcox
2022-06-06 1:34 ` Chen Wandun
2022-06-06 2:08 ` Matthew Wilcox
2022-06-06 2:58 ` Chen Wandun
2022-06-05 3:55 ` [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr Chen Wandun
2022-06-05 3:55 ` [PATCH v2 3/3] mm/shmem: rework calculation of inflated_addr in shmem_get_unmapped_area Chen Wandun
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