destroy code would incorrectly call close() if trans_mod exists after some
hasty code cleanup: we need to make sure we only call close after create
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Reported-by: [email protected]
Reported-by: Leon Romanovsky <[email protected]>
Fixes: 3ff51294a055 ("9p: p9_client_create: use p9_client_destroy on failure")
Signed-off-by: Dominique Martinet <[email protected]>
---
v1->v2: also reset trans on create error
v2->v3: fix silly compile errors
Sorry for the multiple mails, that's what I get for not even doing basic
tests before talking...
net/9p/client.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/net/9p/client.c b/net/9p/client.c
index bfa80f01992e..41e825a8da7c 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -971,6 +971,7 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
spin_lock_init(&clnt->lock);
idr_init(&clnt->fids);
idr_init(&clnt->reqs);
+ clnt->trans = ERR_PTR(-EINVAL);
err = parse_opts(options, clnt);
if (err < 0)
@@ -990,8 +991,14 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
err = clnt->trans_mod->create(clnt, dev_name, options);
- if (err)
+ // ensure clnt->trans is initialized to call close() on destroy
+ // if and only if create succeeded
+ if (err < 0) {
+ clnt->trans = ERR_PTR(err);
goto out;
+ }
+ if (IS_ERR(clnt->trans))
+ clnt->trans = NULL;
if (clnt->msize > clnt->trans_mod->maxsize) {
clnt->msize = clnt->trans_mod->maxsize;
@@ -1036,7 +1043,7 @@ void p9_client_destroy(struct p9_client *clnt)
p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
- if (clnt->trans_mod)
+ if (clnt->trans_mod && !IS_ERR(clnt->trans))
clnt->trans_mod->close(clnt);
v9fs_put_trans(clnt->trans_mod);
--
2.35.1
On Thu, Sep 29, 2022 at 07:19:23AM +0900, Dominique Martinet wrote:
> destroy code would incorrectly call close() if trans_mod exists after some
> hasty code cleanup: we need to make sure we only call close after create
>
> Link: https://lkml.kernel.org/r/[email protected]
> Link: https://lkml.kernel.org/r/[email protected]
> Reported-by: [email protected]
> Reported-by: Leon Romanovsky <[email protected]>
> Fixes: 3ff51294a055 ("9p: p9_client_create: use p9_client_destroy on failure")
> Signed-off-by: Dominique Martinet <[email protected]>
> ---
> v1->v2: also reset trans on create error
> v2->v3: fix silly compile errors
>
> Sorry for the multiple mails, that's what I get for not even doing basic
> tests before talking...
Please always submit new patch versions as new one and don't reply-to.
It breaks flows of everyone who relies on proper email threading.
>
> net/9p/client.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/net/9p/client.c b/net/9p/client.c
> index bfa80f01992e..41e825a8da7c 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -971,6 +971,7 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
> spin_lock_init(&clnt->lock);
> idr_init(&clnt->fids);
> idr_init(&clnt->reqs);
> + clnt->trans = ERR_PTR(-EINVAL);
>
> err = parse_opts(options, clnt);
> if (err < 0)
> @@ -990,8 +991,14 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
> clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
>
> err = clnt->trans_mod->create(clnt, dev_name, options);
> - if (err)
> + // ensure clnt->trans is initialized to call close() on destroy
> + // if and only if create succeeded
Please use /* */ comment style.
> + if (err < 0) {
> + clnt->trans = ERR_PTR(err);
> goto out;
> + }
> + if (IS_ERR(clnt->trans))
> + clnt->trans = NULL;
>
> if (clnt->msize > clnt->trans_mod->maxsize) {
> clnt->msize = clnt->trans_mod->maxsize;
> @@ -1036,7 +1043,7 @@ void p9_client_destroy(struct p9_client *clnt)
>
> p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
>
> - if (clnt->trans_mod)
> + if (clnt->trans_mod && !IS_ERR(clnt->trans))
It is completely no-go to rely on internal value inside of structure after
failure in ->create() callback.
> clnt->trans_mod->close(clnt);
>
> v9fs_put_trans(clnt->trans_mod);
> --
> 2.35.1
>
Leon Romanovsky wrote on Thu, Sep 29, 2022 at 08:54:10AM +0300:
> > + // ensure clnt->trans is initialized to call close() on destroy
> > + // if and only if create succeeded
> > + if (err < 0) {
> > + clnt->trans = ERR_PTR(err);
> > goto out;
> > + }
> > + if (IS_ERR(clnt->trans))
> > + clnt->trans = NULL;
> >
> > if (clnt->msize > clnt->trans_mod->maxsize) {
> > clnt->msize = clnt->trans_mod->maxsize;
> > @@ -1036,7 +1043,7 @@ void p9_client_destroy(struct p9_client *clnt)
> >
> > p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
> >
> > - if (clnt->trans_mod)
> > + if (clnt->trans_mod && !IS_ERR(clnt->trans))
>
> It is completely no-go to rely on internal value inside of structure after
> failure in ->create() callback.
We're overriding the value after ->create(), in both cases that might
pose problem (success without setting trans/failure); I can't see how
that would possibly fail.
But as you've seen in the other commit I am in no shape to write any
decent code and consider the implications of what I'm changing in this
untangled mess, so you know what: I'll just leave this broken.
Please send me a patch if you care, I'm done here.
--
Dominique