* [PATCH] sunrpc: handle ENOMEM in rpcb_getport_async
@ 2018-12-20 15:35 J. Bruce Fields
2018-12-20 15:42 ` [PATCH] sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS J. Bruce Fields
0 siblings, 1 reply; 6+ messages in thread
From: J. Bruce Fields @ 2018-12-20 15:35 UTC (permalink / raw)
To: Trond Myklebust, Anna Schumaker; +Cc: linux-nfs
From: "J. Bruce Fields" <bfields@redhat.com>
If we ignore the error we'll hit a null dereference a little later.
Reported-by: syzbot+4b98281f2401ab849f4b@syzkaller.appspotmail.com
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
net/sunrpc/rpcb_clnt.c | 8 ++++++++
1 file changed, 8 insertions(+)
Looks like this is still a bug?
diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index c7872bc13860..08b5fa4a2852 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -771,6 +771,12 @@ void rpcb_getport_async(struct rpc_task *task)
case RPCBVERS_3:
map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
map->r_addr = rpc_sockaddr2uaddr(sap, GFP_ATOMIC);
+ if (!map->r_addr) {
+ status = -ENOMEM;
+ dprintk("RPC: %5u %s: no memory available\n",
+ task->tk_pid, __func__);
+ goto bailout_free_args;
+ }
map->r_owner = "";
break;
case RPCBVERS_2:
@@ -793,6 +799,8 @@ void rpcb_getport_async(struct rpc_task *task)
rpc_put_task(child);
return;
+bailout_free_args:
+ kfree(map);
bailout_release_client:
rpc_release_client(rpcb_clnt);
bailout_nofree:
--
2.19.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS
2018-12-20 15:35 [PATCH] sunrpc: handle ENOMEM in rpcb_getport_async J. Bruce Fields
@ 2018-12-20 15:42 ` J. Bruce Fields
2018-12-20 15:47 ` Chuck Lever
0 siblings, 1 reply; 6+ messages in thread
From: J. Bruce Fields @ 2018-12-20 15:42 UTC (permalink / raw)
To: Trond Myklebust, Anna Schumaker; +Cc: linux-nfs
From: "J. Bruce Fields" <bfields@redhat.com>
It's OK to sleep here, we just don't want to recurse into the filesystem
as this writeout could be waiting on this.
Future work: the documentation for GFP_NOFS says "Please try to avoid
using this flag directly and instead use memalloc_nofs_{save,restore} to
mark the whole scope which cannot/shouldn't recurse into the FS layer
with a short explanation why. All allocation requests will inherit
GFP_NOFS implicitly."
But I'm not sure where to do this. Should the workqueue be arranging
that for us in the case of workqueues created with WQ_MEM_RECLAIM?
Reported-by: Trond Myklebust <trondmy@hammer.space>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
net/sunrpc/rpcb_clnt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Also, I've still got this one. (And still haven't looked into whether
it should be using a memalloc_nofs_{save,restore} elsewhere instead.)
diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index 08b5fa4a2852..41a971ac1c63 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -752,7 +752,7 @@ void rpcb_getport_async(struct rpc_task *task)
goto bailout_nofree;
}
- map = kzalloc(sizeof(struct rpcbind_args), GFP_ATOMIC);
+ map = kzalloc(sizeof(struct rpcbind_args), GFP_NOFS);
if (!map) {
status = -ENOMEM;
dprintk("RPC: %5u %s: no memory available\n",
@@ -770,7 +770,7 @@ void rpcb_getport_async(struct rpc_task *task)
case RPCBVERS_4:
case RPCBVERS_3:
map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
- map->r_addr = rpc_sockaddr2uaddr(sap, GFP_ATOMIC);
+ map->r_addr = rpc_sockaddr2uaddr(sap, GFP_NOFS);
if (!map->r_addr) {
status = -ENOMEM;
dprintk("RPC: %5u %s: no memory available\n",
--
2.19.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS
2018-12-20 15:42 ` [PATCH] sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS J. Bruce Fields
@ 2018-12-20 15:47 ` Chuck Lever
2018-12-20 15:52 ` Bruce Fields
0 siblings, 1 reply; 6+ messages in thread
From: Chuck Lever @ 2018-12-20 15:47 UTC (permalink / raw)
To: Bruce Fields; +Cc: Trond Myklebust, Anna Schumaker, Linux NFS Mailing List
> On Dec 20, 2018, at 10:42 AM, J. Bruce Fields <bfields@fieldses.org> wrote:
>
> From: "J. Bruce Fields" <bfields@redhat.com>
>
> It's OK to sleep here, we just don't want to recurse into the filesystem
> as this writeout could be waiting on this.
"as a writeout"
> Future work: the documentation for GFP_NOFS says "Please try to avoid
> using this flag directly and instead use memalloc_nofs_{save,restore} to
> mark the whole scope which cannot/shouldn't recurse into the FS layer
> with a short explanation why. All allocation requests will inherit
> GFP_NOFS implicitly."
>
> But I'm not sure where to do this. Should the workqueue be arranging
> that for us in the case of workqueues created with WQ_MEM_RECLAIM?
There seem to be plenty of uses of GFP_NOFS in NFS and sunrpc.
That sounds like a big project.
> Reported-by: Trond Myklebust <trondmy@hammer.space>
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> ---
> net/sunrpc/rpcb_clnt.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> Also, I've still got this one. (And still haven't looked into whether
> it should be using a memalloc_nofs_{save,restore} elsewhere instead.)
>
> diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
> index 08b5fa4a2852..41a971ac1c63 100644
> --- a/net/sunrpc/rpcb_clnt.c
> +++ b/net/sunrpc/rpcb_clnt.c
> @@ -752,7 +752,7 @@ void rpcb_getport_async(struct rpc_task *task)
> goto bailout_nofree;
> }
>
> - map = kzalloc(sizeof(struct rpcbind_args), GFP_ATOMIC);
> + map = kzalloc(sizeof(struct rpcbind_args), GFP_NOFS);
> if (!map) {
> status = -ENOMEM;
> dprintk("RPC: %5u %s: no memory available\n",
> @@ -770,7 +770,7 @@ void rpcb_getport_async(struct rpc_task *task)
> case RPCBVERS_4:
> case RPCBVERS_3:
> map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
> - map->r_addr = rpc_sockaddr2uaddr(sap, GFP_ATOMIC);
> + map->r_addr = rpc_sockaddr2uaddr(sap, GFP_NOFS);
> if (!map->r_addr) {
> status = -ENOMEM;
> dprintk("RPC: %5u %s: no memory available\n",
> --
> 2.19.2
>
--
Chuck Lever
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS
2018-12-20 15:47 ` Chuck Lever
@ 2018-12-20 15:52 ` Bruce Fields
2018-12-20 20:13 ` Bruce Fields
2018-12-21 6:37 ` Trond Myklebust
0 siblings, 2 replies; 6+ messages in thread
From: Bruce Fields @ 2018-12-20 15:52 UTC (permalink / raw)
To: Chuck Lever; +Cc: Trond Myklebust, Anna Schumaker, Linux NFS Mailing List
On Thu, Dec 20, 2018 at 10:47:25AM -0500, Chuck Lever wrote:
>
>
> > On Dec 20, 2018, at 10:42 AM, J. Bruce Fields <bfields@fieldses.org> wrote:
> >
> > From: "J. Bruce Fields" <bfields@redhat.com>
> >
> > It's OK to sleep here, we just don't want to recurse into the filesystem
> > as this writeout could be waiting on this.
>
> "as a writeout"
Oops, thanks.
> > Future work: the documentation for GFP_NOFS says "Please try to avoid
> > using this flag directly and instead use memalloc_nofs_{save,restore} to
> > mark the whole scope which cannot/shouldn't recurse into the FS layer
> > with a short explanation why. All allocation requests will inherit
> > GFP_NOFS implicitly."
> >
> > But I'm not sure where to do this. Should the workqueue be arranging
> > that for us in the case of workqueues created with WQ_MEM_RECLAIM?
>
> There seem to be plenty of uses of GFP_NOFS in NFS and sunrpc.
> That sounds like a big project.
Yeah, just noting it for future reference.
--b.
> > Reported-by: Trond Myklebust <trondmy@hammer.space>
> > Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> > ---
> > net/sunrpc/rpcb_clnt.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > Also, I've still got this one. (And still haven't looked into whether
> > it should be using a memalloc_nofs_{save,restore} elsewhere instead.)
> >
> > diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
> > index 08b5fa4a2852..41a971ac1c63 100644
> > --- a/net/sunrpc/rpcb_clnt.c
> > +++ b/net/sunrpc/rpcb_clnt.c
> > @@ -752,7 +752,7 @@ void rpcb_getport_async(struct rpc_task *task)
> > goto bailout_nofree;
> > }
> >
> > - map = kzalloc(sizeof(struct rpcbind_args), GFP_ATOMIC);
> > + map = kzalloc(sizeof(struct rpcbind_args), GFP_NOFS);
> > if (!map) {
> > status = -ENOMEM;
> > dprintk("RPC: %5u %s: no memory available\n",
> > @@ -770,7 +770,7 @@ void rpcb_getport_async(struct rpc_task *task)
> > case RPCBVERS_4:
> > case RPCBVERS_3:
> > map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
> > - map->r_addr = rpc_sockaddr2uaddr(sap, GFP_ATOMIC);
> > + map->r_addr = rpc_sockaddr2uaddr(sap, GFP_NOFS);
> > if (!map->r_addr) {
> > status = -ENOMEM;
> > dprintk("RPC: %5u %s: no memory available\n",
> > --
> > 2.19.2
> >
>
> --
> Chuck Lever
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS
2018-12-20 15:52 ` Bruce Fields
@ 2018-12-20 20:13 ` Bruce Fields
2018-12-21 6:37 ` Trond Myklebust
1 sibling, 0 replies; 6+ messages in thread
From: Bruce Fields @ 2018-12-20 20:13 UTC (permalink / raw)
To: Chuck Lever; +Cc: Trond Myklebust, Anna Schumaker, Linux NFS Mailing List
On Thu, Dec 20, 2018 at 10:52:19AM -0500, Bruce Fields wrote:
> On Thu, Dec 20, 2018 at 10:47:25AM -0500, Chuck Lever wrote:
> >
> >
> > > On Dec 20, 2018, at 10:42 AM, J. Bruce Fields <bfields@fieldses.org> wrote:
> > >
> > > From: "J. Bruce Fields" <bfields@redhat.com>
> > >
> > > It's OK to sleep here, we just don't want to recurse into the filesystem
> > > as this writeout could be waiting on this.
> >
> > "as a writeout"
>
> Oops, thanks.
(Trond or Anna, I'm assuming you can fix that up, but let me know if
you'd rather I resent.)
--b.
>
> > > Future work: the documentation for GFP_NOFS says "Please try to avoid
> > > using this flag directly and instead use memalloc_nofs_{save,restore} to
> > > mark the whole scope which cannot/shouldn't recurse into the FS layer
> > > with a short explanation why. All allocation requests will inherit
> > > GFP_NOFS implicitly."
> > >
> > > But I'm not sure where to do this. Should the workqueue be arranging
> > > that for us in the case of workqueues created with WQ_MEM_RECLAIM?
> >
> > There seem to be plenty of uses of GFP_NOFS in NFS and sunrpc.
> > That sounds like a big project.
>
> Yeah, just noting it for future reference.
>
> --b.
>
> > > Reported-by: Trond Myklebust <trondmy@hammer.space>
> > > Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> > > ---
> > > net/sunrpc/rpcb_clnt.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > Also, I've still got this one. (And still haven't looked into whether
> > > it should be using a memalloc_nofs_{save,restore} elsewhere instead.)
> > >
> > > diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
> > > index 08b5fa4a2852..41a971ac1c63 100644
> > > --- a/net/sunrpc/rpcb_clnt.c
> > > +++ b/net/sunrpc/rpcb_clnt.c
> > > @@ -752,7 +752,7 @@ void rpcb_getport_async(struct rpc_task *task)
> > > goto bailout_nofree;
> > > }
> > >
> > > - map = kzalloc(sizeof(struct rpcbind_args), GFP_ATOMIC);
> > > + map = kzalloc(sizeof(struct rpcbind_args), GFP_NOFS);
> > > if (!map) {
> > > status = -ENOMEM;
> > > dprintk("RPC: %5u %s: no memory available\n",
> > > @@ -770,7 +770,7 @@ void rpcb_getport_async(struct rpc_task *task)
> > > case RPCBVERS_4:
> > > case RPCBVERS_3:
> > > map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
> > > - map->r_addr = rpc_sockaddr2uaddr(sap, GFP_ATOMIC);
> > > + map->r_addr = rpc_sockaddr2uaddr(sap, GFP_NOFS);
> > > if (!map->r_addr) {
> > > status = -ENOMEM;
> > > dprintk("RPC: %5u %s: no memory available\n",
> > > --
> > > 2.19.2
> > >
> >
> > --
> > Chuck Lever
> >
> >
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS
2018-12-20 15:52 ` Bruce Fields
2018-12-20 20:13 ` Bruce Fields
@ 2018-12-21 6:37 ` Trond Myklebust
1 sibling, 0 replies; 6+ messages in thread
From: Trond Myklebust @ 2018-12-21 6:37 UTC (permalink / raw)
To: bfields, chuck.lever; +Cc: schumakeranna, linux-nfs
On Thu, 2018-12-20 at 10:52 -0500, Bruce Fields wrote:
> On Thu, Dec 20, 2018 at 10:47:25AM -0500, Chuck Lever wrote:
> >
> > > On Dec 20, 2018, at 10:42 AM, J. Bruce Fields <
> > > bfields@fieldses.org> wrote:
> > >
> > > From: "J. Bruce Fields" <bfields@redhat.com>
> > >
> > > It's OK to sleep here, we just don't want to recurse into the
> > > filesystem
> > > as this writeout could be waiting on this.
> >
> > "as a writeout"
>
> Oops, thanks.
>
> > > Future work: the documentation for GFP_NOFS says "Please try to
> > > avoid
> > > using this flag directly and instead use
> > > memalloc_nofs_{save,restore} to
> > > mark the whole scope which cannot/shouldn't recurse into the FS
> > > layer
> > > with a short explanation why. All allocation requests will
> > > inherit
> > > GFP_NOFS implicitly."
> > >
> > > But I'm not sure where to do this. Should the workqueue be
> > > arranging
> > > that for us in the case of workqueues created with
> > > WQ_MEM_RECLAIM?
> >
> > There seem to be plenty of uses of GFP_NOFS in NFS and sunrpc.
> > That sounds like a big project.
>
> Yeah, just noting it for future reference.
>
I'd suggest that we can probably just call memalloc_nofs_save() in
rpc_execute(), and otherwise in those workqueue callback functions that
are executed directly by rpciod and xprtiod. That doesn't make for too
many callsites.
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-12-21 6:37 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2018-12-20 15:35 [PATCH] sunrpc: handle ENOMEM in rpcb_getport_async J. Bruce Fields
2018-12-20 15:42 ` [PATCH] sunrpc: convert unnecessary GFP_ATOMIC to GFP_NOFS J. Bruce Fields
2018-12-20 15:47 ` Chuck Lever
2018-12-20 15:52 ` Bruce Fields
2018-12-20 20:13 ` Bruce Fields
2018-12-21 6:37 ` Trond Myklebust
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