| Message ID | 20210630150234.1109496-2-glider@google.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v4,1/2] kfence: move the size check to the beginning of __kfence_alloc() | expand |
Andrew, This series is ready to be picked up. If possible, kindly consider including it in an upcoming batch of mainline fixes. Thank you! On Wed, 30 Jun 2021 at 17:02, Alexander Potapenko <glider@google.com> wrote: > Allocation requests outside ZONE_NORMAL (MOVABLE, HIGHMEM or DMA) cannot > be fulfilled by KFENCE, because KFENCE memory pool is located in a > zone different from the requested one. > > Because callers of kmem_cache_alloc() may actually rely on the > allocation to reside in the requested zone (e.g. memory allocations done > with __GFP_DMA must be DMAable), skip all allocations done with > GFP_ZONEMASK and/or respective SLAB flags (SLAB_CACHE_DMA and > SLAB_CACHE_DMA32). > > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Dmitry Vyukov <dvyukov@google.com> > Cc: Marco Elver <elver@google.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Souptick Joarder <jrdr.linux@gmail.com> > Cc: stable@vger.kernel.org # 5.12+ > Signed-off-by: Alexander Potapenko <glider@google.com> > Reviewed-by: Marco Elver <elver@google.com> > > --- > > v2: > - added parentheses around the GFP clause, as requested by Marco > v3: > - ignore GFP_ZONEMASK, which also covers __GFP_HIGHMEM and __GFP_MOVABLE > - move the flag check at the beginning of the function, as requested by > Souptick Joarder > v4: > - minor fixes to description and comment formatting > --- > mm/kfence/core.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index 33bb20d91bf6a..1cbdb62e6d0fb 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -740,6 +740,15 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) > if (size > PAGE_SIZE) > return NULL; > > + /* > + * Skip allocations from non-default zones, including DMA. We cannot > + * guarantee that pages in the KFENCE pool will have the requested > + * properties (e.g. reside in DMAable memory). > + */ > + if ((flags & GFP_ZONEMASK) || > + (s->flags & (SLAB_CACHE_DMA | SLAB_CACHE_DMA32))) > + return NULL; > + > /* > * allocation_gate only needs to become non-zero, so it doesn't make > * sense to continue writing to it and pay the associated contention > -- > 2.32.0.93.g670b81a890-goog >
On Wed, Jun 30, 2021 at 8:32 PM Alexander Potapenko <glider@google.com> wrote: > > Allocation requests outside ZONE_NORMAL (MOVABLE, HIGHMEM or DMA) cannot > be fulfilled by KFENCE, because KFENCE memory pool is located in a > zone different from the requested one. > > Because callers of kmem_cache_alloc() may actually rely on the > allocation to reside in the requested zone (e.g. memory allocations done > with __GFP_DMA must be DMAable), skip all allocations done with > GFP_ZONEMASK and/or respective SLAB flags (SLAB_CACHE_DMA and > SLAB_CACHE_DMA32). > > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Dmitry Vyukov <dvyukov@google.com> > Cc: Marco Elver <elver@google.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Souptick Joarder <jrdr.linux@gmail.com> > Cc: stable@vger.kernel.org # 5.12+ > Signed-off-by: Alexander Potapenko <glider@google.com> > Reviewed-by: Marco Elver <elver@google.com> > > --- > > v2: > - added parentheses around the GFP clause, as requested by Marco > v3: > - ignore GFP_ZONEMASK, which also covers __GFP_HIGHMEM and __GFP_MOVABLE > - move the flag check at the beginning of the function, as requested by > Souptick Joarder Acked-by: Souptick Joarder <jrdr.linux@gmail.com> > v4: > - minor fixes to description and comment formatting > --- > mm/kfence/core.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index 33bb20d91bf6a..1cbdb62e6d0fb 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -740,6 +740,15 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) > if (size > PAGE_SIZE) > return NULL; > > + /* > + * Skip allocations from non-default zones, including DMA. We cannot > + * guarantee that pages in the KFENCE pool will have the requested > + * properties (e.g. reside in DMAable memory). > + */ > + if ((flags & GFP_ZONEMASK) || > + (s->flags & (SLAB_CACHE_DMA | SLAB_CACHE_DMA32))) > + return NULL; > + > /* > * allocation_gate only needs to become non-zero, so it doesn't make > * sense to continue writing to it and pay the associated contention > -- > 2.32.0.93.g670b81a890-goog >
On Mon, 5 Jul 2021 at 16:05, Marco Elver <elver@google.com> wrote: > Andrew, > > This series is ready to be picked up. > > If possible, kindly consider including it in an upcoming batch of > mainline fixes. > > Thank you! It'd be good to get this sorted -- please take another look. Many thanks, -- Marco > On Wed, 30 Jun 2021 at 17:02, Alexander Potapenko <glider@google.com> wrote: > > Allocation requests outside ZONE_NORMAL (MOVABLE, HIGHMEM or DMA) cannot > > be fulfilled by KFENCE, because KFENCE memory pool is located in a > > zone different from the requested one. > > > > Because callers of kmem_cache_alloc() may actually rely on the > > allocation to reside in the requested zone (e.g. memory allocations done > > with __GFP_DMA must be DMAable), skip all allocations done with > > GFP_ZONEMASK and/or respective SLAB flags (SLAB_CACHE_DMA and > > SLAB_CACHE_DMA32). > > > > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") > > Cc: Andrew Morton <akpm@linux-foundation.org> > > Cc: Dmitry Vyukov <dvyukov@google.com> > > Cc: Marco Elver <elver@google.com> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Cc: Souptick Joarder <jrdr.linux@gmail.com> > > Cc: stable@vger.kernel.org # 5.12+ > > Signed-off-by: Alexander Potapenko <glider@google.com> > > Reviewed-by: Marco Elver <elver@google.com> > > > > --- > > > > v2: > > - added parentheses around the GFP clause, as requested by Marco > > v3: > > - ignore GFP_ZONEMASK, which also covers __GFP_HIGHMEM and __GFP_MOVABLE > > - move the flag check at the beginning of the function, as requested by > > Souptick Joarder > > v4: > > - minor fixes to description and comment formatting > > --- > > mm/kfence/core.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > > > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > > index 33bb20d91bf6a..1cbdb62e6d0fb 100644 > > --- a/mm/kfence/core.c > > +++ b/mm/kfence/core.c > > @@ -740,6 +740,15 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) > > if (size > PAGE_SIZE) > > return NULL; > > > > + /* > > + * Skip allocations from non-default zones, including DMA. We cannot > > + * guarantee that pages in the KFENCE pool will have the requested > > + * properties (e.g. reside in DMAable memory). > > + */ > > + if ((flags & GFP_ZONEMASK) || > > + (s->flags & (SLAB_CACHE_DMA | SLAB_CACHE_DMA32))) > > + return NULL; > > + > > /* > > * allocation_gate only needs to become non-zero, so it doesn't make > > * sense to continue writing to it and pay the associated contention > > -- > > 2.32.0.93.g670b81a890-goog > >
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 33bb20d91bf6a..1cbdb62e6d0fb 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -740,6 +740,15 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) if (size > PAGE_SIZE) return NULL; + /* + * Skip allocations from non-default zones, including DMA. We cannot + * guarantee that pages in the KFENCE pool will have the requested + * properties (e.g. reside in DMAable memory). + */ + if ((flags & GFP_ZONEMASK) || + (s->flags & (SLAB_CACHE_DMA | SLAB_CACHE_DMA32))) + return NULL; + /* * allocation_gate only needs to become non-zero, so it doesn't make * sense to continue writing to it and pay the associated contention
Allocation requests outside ZONE_NORMAL (MOVABLE, HIGHMEM or DMA) cannot be fulfilled by KFENCE, because KFENCE memory pool is located in a zone different from the requested one. Because callers of kmem_cache_alloc() may actually rely on the allocation to reside in the requested zone (e.g. memory allocations done with __GFP_DMA must be DMAable), skip all allocations done with GFP_ZONEMASK and/or respective SLAB flags (SLAB_CACHE_DMA and SLAB_CACHE_DMA32). Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: stable@vger.kernel.org # 5.12+ Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: Marco Elver <elver@google.com> --- v2: - added parentheses around the GFP clause, as requested by Marco v3: - ignore GFP_ZONEMASK, which also covers __GFP_HIGHMEM and __GFP_MOVABLE - move the flag check at the beginning of the function, as requested by Souptick Joarder v4: - minor fixes to description and comment formatting --- mm/kfence/core.c | 9 +++++++++ 1 file changed, 9 insertions(+)