Am 09.11.20 um 17:18 schrieb Ville Syrjälä:
On Mon, Nov 09, 2020 at 04:57:29PM +0100, Christian König wrote:
Am 09.11.20 um 16:16 schrieb Ville Syrjälä:
On Wed, Nov 11, 2020 at 06:13:02PM +0100, Christian König wrote:
Am 09.11.20 um 01:54 schrieb Dave Airlie:
@@ -1432,15 +1479,18 @@ int ttm_bo_swapout(struct ttm_operation_ctx *ctx)
if (bo->mem.mem_type != TTM_PL_SYSTEM) {
struct ttm_operation_ctx ctx = { false, false };
struct ttm_resource evict_mem;
+ struct ttm_place hop = {};
Please always use memset() if you want to zero initialize something in
the kernel, we had enough trouble with that.
What trouble is that? I've not heard of anything, and we use
={} quite extensively in drm land.
={} initializes only named fields, not padding.
Has that actually happened?
YES! Numerous times!
And the first few times it took us weeks to figure out what was actually
happening.
Christian.
The result is that for example when doing a hash or CRC of a structure
you can come up with different results depending on the architecture
and/or structure layout.
Another problem are information leaks from the kernel to userspace
because of this.
Because of this Mesa for example strongly discourages using ={} for
zeroing a structure.
Regards,
Christian.
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