Messages in this thread | | | Date | Thu, 22 May 2008 18:03:27 +0200 | From | Marcin Slusarz <> | Subject | Re: [PATCH 1/6] ERR_PTR: if errno value is known at compile time, make sure it's valid |
| |
On Mon, May 19, 2008 at 10:38:52AM +0400, Alexey Dobriyan wrote: > On Sun, May 18, 2008 at 11:56:53PM +0200, Marcin Slusarz wrote: > > ERR_PTR is easy to call with wrong argument (positive errno), > > and this error lead to catastrophic event - oops or kernel panic > > (dereference of invalid pointer). > > > > As most of error handling code paths are rarely tested, this kind of > > bug can be hidden for years. > > > > (Currently there are > 1400 calls of ERR_PTR with constant argument.) > > > --- a/include/linux/err.h > > +++ b/include/linux/err.h > > @@ -19,11 +19,13 @@ > > > > #define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO) > > > > -static inline void *ERR_PTR(long error) > > +static inline void *__ERR_PTR(long error) > > { > > return (void *) error; > > } > > > > +#define ERR_PTR(error) (BUILD_BUG_ON(__builtin_constant_p(error) && !IS_ERR_VALUE(error)), __ERR_PTR(error)) > > This needs comment that this construct must be a macro, otherwise gcc > does something stupid and doesn't break the build (at least in the case > below). Thanks, added to new version.
> BTW, I used grep(1) to find it.
http://lkml.org/lkml/2008/5/11/159
> > [PATCH] xprtrdma: fix ERR_PTR(E typo > > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> > --- > > net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c > +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c > @@ -661,7 +661,7 @@ static struct svc_xprt *svc_rdma_create(struct svc_serv *serv, > > cma_xprt = rdma_create_xprt(serv, 1); > if (!cma_xprt) > - return ERR_PTR(ENOMEM); > + return ERR_PTR(-ENOMEM); > xprt = &cma_xprt->sc_xprt; > > listen_id = rdma_create_id(rdma_listen_handler, cma_xprt, RDMA_PS_TCP); >
| |