On Wed, Jan 23, 2019 at 5:26 PM Rafael Antognolli < [email protected]> wrote:
> Accessing bo->map and then pool->center_bo_offset without a lock is > racy. One way of avoiding such race condition is to store the bo->map + > center_bo_offset into pool->map at the time the block pool is growing, > which happens within a lock. > > v2: Only set pool->map if not using softpin (Jason). > > Cc: Jason Ekstrand <[email protected]> > Reported-by: Ian Romanick <[email protected]> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109442 > Fixes: fc3f58832015cbb177179e7f3420d3611479b4a9 > --- > src/intel/vulkan/anv_allocator.c | 11 +++++++++-- > src/intel/vulkan/anv_private.h | 13 +++++++++++++ > 2 files changed, 22 insertions(+), 2 deletions(-) > > diff --git a/src/intel/vulkan/anv_allocator.c > b/src/intel/vulkan/anv_allocator.c > index 89f26789c85..67f9c2a948d 100644 > --- a/src/intel/vulkan/anv_allocator.c > +++ b/src/intel/vulkan/anv_allocator.c > @@ -437,6 +437,7 @@ anv_block_pool_init(struct anv_block_pool *pool, > pool->nbos = 0; > pool->size = 0; > pool->start_address = gen_canonical_address(start_address); > + pool->map = NULL; > > /* This pointer will always point to the first BO in the list */ > pool->bo = &pool->bos[0]; > @@ -576,6 +577,8 @@ anv_block_pool_expand_range(struct anv_block_pool > *pool, > /* Now that we successfull allocated everything, we can write the new > * center_bo_offset back into pool. */ > pool->center_bo_offset = center_bo_offset; > + if (!use_softpin) > + pool->map = map + center_bo_offset; > We could also put this a bit higher up right after where we actually call mmap. That would reduce the number of "if (use_softpin)" blocks and probably make things more readable. Come to think of it, we could also set pool->center_bo_offset there and just assert(center_bo_offset == 0) in the softpin case. I like that. Maybe that's a second patch? In any case, this fixes today's bug Reviewed-by: Jason Ekstrand <[email protected]> --Jason > > /* For block pool BOs we have to be a bit careful about where we place > them > * in the GTT. There are two documented workarounds for state base > address > @@ -670,8 +673,12 @@ anv_block_pool_get_bo(struct anv_block_pool *pool, > int32_t *offset) > void* > anv_block_pool_map(struct anv_block_pool *pool, int32_t offset) > { > - struct anv_bo *bo = anv_block_pool_get_bo(pool, &offset); > - return bo->map + pool->center_bo_offset + offset; > + if (pool->bo_flags & EXEC_OBJECT_PINNED) { > + struct anv_bo *bo = anv_block_pool_get_bo(pool, &offset); > + return bo->map + offset; > + } else { > + return pool->map + offset; > + } > } > > /** Grows and re-centers the block pool. > diff --git a/src/intel/vulkan/anv_private.h > b/src/intel/vulkan/anv_private.h > index 3889065c93c..110b2ccf023 100644 > --- a/src/intel/vulkan/anv_private.h > +++ b/src/intel/vulkan/anv_private.h > @@ -663,6 +663,19 @@ struct anv_block_pool { > */ > uint32_t center_bo_offset; > > + /* Current memory map of the block pool. This pointer may or may not > + * point to the actual beginning of the block pool memory. If > + * anv_block_pool_alloc_back has ever been called, then this pointer > + * will point to the "center" position of the buffer and all offsets > + * (negative or positive) given out by the block pool alloc functions > + * will be valid relative to this pointer. > + * > + * In particular, map == bo.map + center_offset > + * > + * DO NOT access this pointer directly. Use anv_block_pool_map() > instead, > + * since it will handle the softpin case as well, where this points to > NULL. > + */ > + void *map; > int fd; > > /** > -- > 2.17.2 > >
_______________________________________________ mesa-dev mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-dev
