| Message ID | 20180725150950.23298-1-ap420073@gmail.com |
|---|---|
| State | Superseded, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [V2,bpf] xdp: add NULL pointer check in __xdp_return() | expand |
On Thu, Jul 26, 2018 at 12:09:50AM +0900, Taehee Yoo wrote: > rhashtable_lookup() can return NULL. so that NULL pointer > check routine should be added. > > Fixes: 02b55e5657c3 ("xdp: add MEM_TYPE_ZERO_COPY") > Signed-off-by: Taehee Yoo <ap420073@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> > --- > V2 : add WARN_ON_ONCE when xa is NULL. > > net/core/xdp.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 9d1f220..786fdbe 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -345,7 +345,10 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, > rcu_read_lock(); > /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ > xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); > - xa->zc_alloc->free(xa->zc_alloc, handle); > + if (!xa) > + WARN_ON_ONCE(1); > + else > + xa->zc_alloc->free(xa->zc_alloc, handle); > rcu_read_unlock(); > default: > /* Not possible, checked in xdp_rxq_info_reg_mem_model() */ > -- > 2.9.3 >
On Thu, 26 Jul 2018 00:09:50 +0900, Taehee Yoo wrote: > rhashtable_lookup() can return NULL. so that NULL pointer > check routine should be added. > > Fixes: 02b55e5657c3 ("xdp: add MEM_TYPE_ZERO_COPY") > Signed-off-by: Taehee Yoo <ap420073@gmail.com> > --- > V2 : add WARN_ON_ONCE when xa is NULL. > > net/core/xdp.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/net/core/xdp.c b/net/core/xdp.c > index 9d1f220..786fdbe 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -345,7 +345,10 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, > rcu_read_lock(); > /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ > xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); > - xa->zc_alloc->free(xa->zc_alloc, handle); > + if (!xa) > + WARN_ON_ONCE(1); nit: is compiler smart enough to figure out the fast path here? WARN_ON_ONCE() has the nice side effect of wrapping the condition in unlikely(). It could save us both LoC and potentially cycles to do: if (!WARN_ON_ONCE(!xa)) xa->zc_alloc->free(xa->zc_alloc, handle); Although it admittedly looks a bit awkward. I'm not sure if we have some form of assert (i.e. positive check) in tree :S > + else > + xa->zc_alloc->free(xa->zc_alloc, handle); > rcu_read_unlock(); > default: > /* Not possible, checked in xdp_rxq_info_reg_mem_model() */
Den tors 26 juli 2018 kl 04:14 skrev Jakub Kicinski <jakub.kicinski@netronome.com>: > > On Thu, 26 Jul 2018 00:09:50 +0900, Taehee Yoo wrote: > > rhashtable_lookup() can return NULL. so that NULL pointer > > check routine should be added. > > > > Fixes: 02b55e5657c3 ("xdp: add MEM_TYPE_ZERO_COPY") > > Signed-off-by: Taehee Yoo <ap420073@gmail.com> > > --- > > V2 : add WARN_ON_ONCE when xa is NULL. > > > > net/core/xdp.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/net/core/xdp.c b/net/core/xdp.c > > index 9d1f220..786fdbe 100644 > > --- a/net/core/xdp.c > > +++ b/net/core/xdp.c > > @@ -345,7 +345,10 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, > > rcu_read_lock(); > > /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ > > xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); > > - xa->zc_alloc->free(xa->zc_alloc, handle); > > + if (!xa) > > + WARN_ON_ONCE(1); > > nit: is compiler smart enough to figure out the fast path here? > WARN_ON_ONCE() has the nice side effect of wrapping the condition in > unlikely(). It could save us both LoC and potentially cycles to do: > > if (!WARN_ON_ONCE(!xa)) > xa->zc_alloc->free(xa->zc_alloc, handle); > > Although it admittedly looks a bit awkward. I'm not sure if we have > some form of assert (i.e. positive check) in tree :S > I'm kind of in favor of this ^^^. Hopefully, Taehee is ok with another spin. Björn > > + else > > + xa->zc_alloc->free(xa->zc_alloc, handle); > > rcu_read_unlock(); > > default: > > /* Not possible, checked in xdp_rxq_info_reg_mem_model() */
2018-07-26 11:11 GMT+09:00 Jakub Kicinski <jakub.kicinski@netronome.com>: > On Thu, 26 Jul 2018 00:09:50 +0900, Taehee Yoo wrote: >> rhashtable_lookup() can return NULL. so that NULL pointer >> check routine should be added. >> >> Fixes: 02b55e5657c3 ("xdp: add MEM_TYPE_ZERO_COPY") >> Signed-off-by: Taehee Yoo <ap420073@gmail.com> >> --- >> V2 : add WARN_ON_ONCE when xa is NULL. >> >> net/core/xdp.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/net/core/xdp.c b/net/core/xdp.c >> index 9d1f220..786fdbe 100644 >> --- a/net/core/xdp.c >> +++ b/net/core/xdp.c >> @@ -345,7 +345,10 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, >> rcu_read_lock(); >> /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ >> xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); >> - xa->zc_alloc->free(xa->zc_alloc, handle); >> + if (!xa) >> + WARN_ON_ONCE(1); > > nit: is compiler smart enough to figure out the fast path here? > WARN_ON_ONCE() has the nice side effect of wrapping the condition in > unlikely(). It could save us both LoC and potentially cycles to do: > > if (!WARN_ON_ONCE(!xa)) > xa->zc_alloc->free(xa->zc_alloc, handle); > > Although it admittedly looks a bit awkward. I'm not sure if we have > some form of assert (i.e. positive check) in tree :S > Thank you for suggestion! I like this code style and I think there is no problem because readers are familiar with this code style. I will send v3 patch! Thanks! >> + else >> + xa->zc_alloc->free(xa->zc_alloc, handle); >> rcu_read_unlock(); >> default: >> /* Not possible, checked in xdp_rxq_info_reg_mem_model() */
2018-07-26 21:07 GMT+09:00 Björn Töpel <bjorn.topel@gmail.com>: > Den tors 26 juli 2018 kl 04:14 skrev Jakub Kicinski > <jakub.kicinski@netronome.com>: >> >> On Thu, 26 Jul 2018 00:09:50 +0900, Taehee Yoo wrote: >> > rhashtable_lookup() can return NULL. so that NULL pointer >> > check routine should be added. >> > >> > Fixes: 02b55e5657c3 ("xdp: add MEM_TYPE_ZERO_COPY") >> > Signed-off-by: Taehee Yoo <ap420073@gmail.com> >> > --- >> > V2 : add WARN_ON_ONCE when xa is NULL. >> > >> > net/core/xdp.c | 5 ++++- >> > 1 file changed, 4 insertions(+), 1 deletion(-) >> > >> > diff --git a/net/core/xdp.c b/net/core/xdp.c >> > index 9d1f220..786fdbe 100644 >> > --- a/net/core/xdp.c >> > +++ b/net/core/xdp.c >> > @@ -345,7 +345,10 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, >> > rcu_read_lock(); >> > /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ >> > xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); >> > - xa->zc_alloc->free(xa->zc_alloc, handle); >> > + if (!xa) >> > + WARN_ON_ONCE(1); >> >> nit: is compiler smart enough to figure out the fast path here? >> WARN_ON_ONCE() has the nice side effect of wrapping the condition in >> unlikely(). It could save us both LoC and potentially cycles to do: >> >> if (!WARN_ON_ONCE(!xa)) >> xa->zc_alloc->free(xa->zc_alloc, handle); >> >> Although it admittedly looks a bit awkward. I'm not sure if we have >> some form of assert (i.e. positive check) in tree :S >> > > I'm kind of in favor of this ^^^. Hopefully, Taehee is ok with another spin. > I like this code style and I think it has performance benefit. So I will send v3 patch! Thanks! > Björn > >> > + else >> > + xa->zc_alloc->free(xa->zc_alloc, handle); >> > rcu_read_unlock(); >> > default: >> > /* Not possible, checked in xdp_rxq_info_reg_mem_model() */
diff --git a/net/core/xdp.c b/net/core/xdp.c index 9d1f220..786fdbe 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -345,7 +345,10 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, rcu_read_lock(); /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */ xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); - xa->zc_alloc->free(xa->zc_alloc, handle); + if (!xa) + WARN_ON_ONCE(1); + else + xa->zc_alloc->free(xa->zc_alloc, handle); rcu_read_unlock(); default: /* Not possible, checked in xdp_rxq_info_reg_mem_model() */
rhashtable_lookup() can return NULL. so that NULL pointer check routine should be added. Fixes: 02b55e5657c3 ("xdp: add MEM_TYPE_ZERO_COPY") Signed-off-by: Taehee Yoo <ap420073@gmail.com> --- V2 : add WARN_ON_ONCE when xa is NULL. net/core/xdp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)