2023-01-29 04:44:59

by Dai Ngo

Subject: [PATCH v2 1/1] NFSD: fix problems with cleanup on errors in nfsd4_copy

When nfsd4_copy fails to allocate memory for async_copy->cp_src, or
nfs4_init_copy_state fails, it calls cleanup_async_copy to do the
cleanup for the async_copy which causes page fault since async_copy
is not yet initialized.

This patch rearranges the order of initializing the fields in
async_copy and adds checks in cleanup_async_copy to skip un-initialized
fields.

Fixes: ce0887ac96d3 ("NFSD add nfs4 inter ssc to nfsd4_copy")
Fixes: 87689df69491 ("NFSD: Shrink size of struct nfsd4_copy")
Signed-off-by: Dai Ngo <[email protected]>
---
fs/nfsd/nfs4proc.c | 12 ++++++++----
fs/nfsd/nfs4state.c | 5 +++--
2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 57f791899de3..0754b38d3a43 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1687,9 +1687,12 @@ static void cleanup_async_copy(struct nfsd4_copy *copy)
{
nfs4_free_copy_state(copy);
release_copy_files(copy);
- spin_lock(&copy->cp_clp->async_lock);
- list_del(&copy->copies);
- spin_unlock(&copy->cp_clp->async_lock);
+ if (copy->cp_clp) {
+ spin_lock(&copy->cp_clp->async_lock);
+ if (!list_empty(&copy->copies))
+ list_del(&copy->copies);
+ spin_unlock(&copy->cp_clp->async_lock);
+ }
nfs4_put_copy(copy);
}

@@ -1786,12 +1789,13 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
if (!async_copy)
goto out_err;
+ INIT_LIST_HEAD(&async_copy->copies);
+ refcount_set(&async_copy->refcount, 1);
async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL);
if (!async_copy->cp_src)
goto out_err;
if (!nfs4_init_copy_state(nn, copy))
goto out_err;
- refcount_set(&async_copy->refcount, 1);
memcpy(&copy->cp_res.cb_stateid, &copy->cp_stateid.cs_stid,
sizeof(copy->cp_res.cb_stateid));
dup_copy_fields(copy, async_copy);
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index ace02fd0d590..c39e43742dd6 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -975,7 +975,6 @@ static int nfs4_init_cp_state(struct nfsd_net *nn, copy_stateid_t *stid,

stid->cs_stid.si_opaque.so_clid.cl_boot = (u32)nn->boot_time;
stid->cs_stid.si_opaque.so_clid.cl_id = nn->s2s_cp_cl_id;
- stid->cs_type = cs_type;

idr_preload(GFP_KERNEL);
spin_lock(&nn->s2s_cp_lock);
@@ -986,6 +985,7 @@ static int nfs4_init_cp_state(struct nfsd_net *nn, copy_stateid_t *stid,
idr_preload_end();
if (new_id < 0)
return 0;
+ stid->cs_type = cs_type;
return 1;
}

@@ -1019,7 +1019,8 @@ void nfs4_free_copy_state(struct nfsd4_copy *copy)
{
struct nfsd_net *nn;

- WARN_ON_ONCE(copy->cp_stateid.cs_type != NFS4_COPY_STID);
+ if (copy->cp_stateid.cs_type != NFS4_COPY_STID)
+ return;
nn = net_generic(copy->cp_clp->net, nfsd_net_id);
spin_lock(&nn->s2s_cp_lock);
idr_remove(&nn->s2s_cp_stateids,
--
2.9.5

2023-01-31 13:36:38

by Jeff Layton

Subject: Re: [PATCH v2 1/1] NFSD: fix problems with cleanup on errors in nfsd4_copy

On Sat, 2023-01-28 at 20:44 -0800, Dai Ngo wrote:
> When nfsd4_copy fails to allocate memory for async_copy->cp_src, or
> nfs4_init_copy_state fails, it calls cleanup_async_copy to do the
> cleanup for the async_copy which causes page fault since async_copy
> is not yet initialized.
>
> This patch rearranges the order of initializing the fields in
> async_copy and adds checks in cleanup_async_copy to skip un-initialized
> fields.
>
> Fixes: ce0887ac96d3 ("NFSD add nfs4 inter ssc to nfsd4_copy")
> Fixes: 87689df69491 ("NFSD: Shrink size of struct nfsd4_copy")
> Signed-off-by: Dai Ngo <[email protected]>
> ---
> fs/nfsd/nfs4proc.c | 12 ++++++++----
> fs/nfsd/nfs4state.c | 5 +++--
> 2 files changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 57f791899de3..0754b38d3a43 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1687,9 +1687,12 @@ static void cleanup_async_copy(struct nfsd4_copy *copy)
> {
> nfs4_free_copy_state(copy);
> release_copy_files(copy);
> - spin_lock(&copy->cp_clp->async_lock);
> - list_del(&copy->copies);
> - spin_unlock(&copy->cp_clp->async_lock);
> + if (copy->cp_clp) {
> + spin_lock(&copy->cp_clp->async_lock);
> + if (!list_empty(&copy->copies))
> + list_del(&copy->copies);

Can we make this a list_del_init? If cleanup_async_copy were called on
this twice, then the second time could end up corrupting the
async_copies list. The cost difference is negligible here.

> + spin_unlock(&copy->cp_clp->async_lock);
> + }
> nfs4_put_copy(copy);
> }
>
> @@ -1786,12 +1789,13 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
> async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
> if (!async_copy)
> goto out_err;
> + INIT_LIST_HEAD(&async_copy->copies);
> + refcount_set(&async_copy->refcount, 1);
> async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL);
> if (!async_copy->cp_src)
> goto out_err;
> if (!nfs4_init_copy_state(nn, copy))
> goto out_err;
> - refcount_set(&async_copy->refcount, 1);
> memcpy(&copy->cp_res.cb_stateid, &copy->cp_stateid.cs_stid,
> sizeof(copy->cp_res.cb_stateid));
> dup_copy_fields(copy, async_copy);
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index ace02fd0d590..c39e43742dd6 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -975,7 +975,6 @@ static int nfs4_init_cp_state(struct nfsd_net *nn, copy_stateid_t *stid,
>
> stid->cs_stid.si_opaque.so_clid.cl_boot = (u32)nn->boot_time;
> stid->cs_stid.si_opaque.so_clid.cl_id = nn->s2s_cp_cl_id;
> - stid->cs_type = cs_type;
>
> idr_preload(GFP_KERNEL);
> spin_lock(&nn->s2s_cp_lock);
> @@ -986,6 +985,7 @@ static int nfs4_init_cp_state(struct nfsd_net *nn, copy_stateid_t *stid,
> idr_preload_end();
> if (new_id < 0)
> return 0;
> + stid->cs_type = cs_type;
> return 1;
> }
>
> @@ -1019,7 +1019,8 @@ void nfs4_free_copy_state(struct nfsd4_copy *copy)
> {
> struct nfsd_net *nn;
>
> - WARN_ON_ONCE(copy->cp_stateid.cs_type != NFS4_COPY_STID);
> + if (copy->cp_stateid.cs_type != NFS4_COPY_STID)
> + return;

It's probably fine to keep the WARN_ON_ONCE here. You're testing the
condition anyway so you can do:

if (WARN_ON_ONCE(copy->cp_stateid.cs_type != NFS4_COPY_STID))


> nn = net_generic(copy->cp_clp->net, nfsd_net_id);
> spin_lock(&nn->s2s_cp_lock);
> idr_remove(&nn->s2s_cp_stateids,

--
Jeff Layton <[email protected]>

2023-01-31 14:27:30

by Chuck Lever III

Subject: Re: [PATCH v2 1/1] NFSD: fix problems with cleanup on errors in nfsd4_copy

> On Jan 31, 2023, at 8:36 AM, Jeff Layton <[email protected]> wrote:
>
> On Sat, 2023-01-28 at 20:44 -0800, Dai Ngo wrote:
>> When nfsd4_copy fails to allocate memory for async_copy->cp_src, or
>> nfs4_init_copy_state fails, it calls cleanup_async_copy to do the
>> cleanup for the async_copy which causes page fault since async_copy
>> is not yet initialized.
>>
>> This patch rearranges the order of initializing the fields in
>> async_copy and adds checks in cleanup_async_copy to skip un-initialized
>> fields.
>>
>> Fixes: ce0887ac96d3 ("NFSD add nfs4 inter ssc to nfsd4_copy")
>> Fixes: 87689df69491 ("NFSD: Shrink size of struct nfsd4_copy")
>> Signed-off-by: Dai Ngo <[email protected]>
>> ---
>> fs/nfsd/nfs4proc.c | 12 ++++++++----
>> fs/nfsd/nfs4state.c | 5 +++--
>> 2 files changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
>> index 57f791899de3..0754b38d3a43 100644
>> --- a/fs/nfsd/nfs4proc.c
>> +++ b/fs/nfsd/nfs4proc.c
>> @@ -1687,9 +1687,12 @@ static void cleanup_async_copy(struct nfsd4_copy *copy)
>> {
>> nfs4_free_copy_state(copy);
>> release_copy_files(copy);
>> - spin_lock(&copy->cp_clp->async_lock);
>> - list_del(&copy->copies);
>> - spin_unlock(&copy->cp_clp->async_lock);
>> + if (copy->cp_clp) {
>> + spin_lock(&copy->cp_clp->async_lock);
>> + if (!list_empty(&copy->copies))
>> + list_del(&copy->copies);
>
> Can we make this a list_del_init? If cleanup_async_copy were called on
> this twice, then the second time could end up corrupting the
> async_copies list. The cost difference is negligible here.

I noticed this yesterday and made the change in my tree.


>> + spin_unlock(&copy->cp_clp->async_lock);
>> + }
>> nfs4_put_copy(copy);
>> }
>>
>> @@ -1786,12 +1789,13 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>> async_copy = kzalloc(sizeof(struct nfsd4_copy), GFP_KERNEL);
>> if (!async_copy)
>> goto out_err;
>> + INIT_LIST_HEAD(&async_copy->copies);
>> + refcount_set(&async_copy->refcount, 1);
>> async_copy->cp_src = kmalloc(sizeof(*async_copy->cp_src), GFP_KERNEL);
>> if (!async_copy->cp_src)
>> goto out_err;
>> if (!nfs4_init_copy_state(nn, copy))
>> goto out_err;
>> - refcount_set(&async_copy->refcount, 1);
>> memcpy(&copy->cp_res.cb_stateid, &copy->cp_stateid.cs_stid,
>> sizeof(copy->cp_res.cb_stateid));
>> dup_copy_fields(copy, async_copy);
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index ace02fd0d590..c39e43742dd6 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -975,7 +975,6 @@ static int nfs4_init_cp_state(struct nfsd_net *nn, copy_stateid_t *stid,
>>
>> stid->cs_stid.si_opaque.so_clid.cl_boot = (u32)nn->boot_time;
>> stid->cs_stid.si_opaque.so_clid.cl_id = nn->s2s_cp_cl_id;
>> - stid->cs_type = cs_type;
>>
>> idr_preload(GFP_KERNEL);
>> spin_lock(&nn->s2s_cp_lock);
>> @@ -986,6 +985,7 @@ static int nfs4_init_cp_state(struct nfsd_net *nn, copy_stateid_t *stid,
>> idr_preload_end();
>> if (new_id < 0)
>> return 0;
>> + stid->cs_type = cs_type;
>> return 1;
>> }
>>
>> @@ -1019,7 +1019,8 @@ void nfs4_free_copy_state(struct nfsd4_copy *copy)
>> {
>> struct nfsd_net *nn;
>>
>> - WARN_ON_ONCE(copy->cp_stateid.cs_type != NFS4_COPY_STID);
>> + if (copy->cp_stateid.cs_type != NFS4_COPY_STID)
>> + return;
>
> It's probably fine to keep the WARN_ON_ONCE here. You're testing the
> condition anyway so you can do:
>
> if (WARN_ON_ONCE(copy->cp_stateid.cs_type != NFS4_COPY_STID))

Six of one...

I'm OK leaving the WARN out, it doesn't seem high value to me.


>> nn = net_generic(copy->cp_clp->net, nfsd_net_id);
>> spin_lock(&nn->s2s_cp_lock);
>> idr_remove(&nn->s2s_cp_stateids,
>
> --
> Jeff Layton <[email protected]>

--
Chuck Lever