Messages in this thread Patch in this message | | | Date | Mon, 19 May 2008 10:38:52 +0400 | From | Alexey Dobriyan <> | Subject | Re: [PATCH 1/6] ERR_PTR: if errno value is known at compile time, make sure it's valid |
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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). BTW, I used grep(1) to find it.
[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);
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