From 6f39dd9038487b1596b85719195c964c4f291f32 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Sun, 10 Nov 2019 22:08:12 +0000 Subject: [PATCH] drm/i915/cmdparser: Fix jump whitelist clearing When a jump_whitelist bitmap is reused, it needs to be cleared. Currently this is done with memset() and the size calculation assumes bitmaps are made of 32-bit words, not longs. So on 64-bit architectures, only the first half of the bitmap is cleared. If some whitelist bits are carried over between successive batches submitted on the same context, this will presumably allow embedding the rogue instructions that we're trying to reject. Use bitmap_zero() instead, which gets the calculation right. Fixes: f8c08d8faee5 ("drm/i915/cmdparser: Add support for backward jumps") Cc: stable@vger.kernel.org Signed-off-by: Ben Hutchings Gbp-Pq: Topic bugfix/x86/i915 Gbp-Pq: Name drm-i915-cmdparser-fix-jump-whitelist-clearing.patch --- drivers/gpu/drm/i915/i915_cmd_parser.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c index efb6d0727ee..a412e346b29 100644 --- a/drivers/gpu/drm/i915/i915_cmd_parser.c +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c @@ -1374,7 +1374,7 @@ static void init_whitelist(struct i915_gem_context *ctx, u32 batch_len) return; if (batch_cmds <= ctx->jump_whitelist_cmds) { - memset(ctx->jump_whitelist, 0, exact_size * sizeof(u32)); + bitmap_zero(ctx->jump_whitelist, batch_cmds); return; } @@ -1394,8 +1394,7 @@ again: } DRM_DEBUG("CMD: Failed to extend whitelist. BB_START may be disallowed\n"); - memset(ctx->jump_whitelist, 0, - BITS_TO_LONGS(ctx->jump_whitelist_cmds) * sizeof(u32)); + bitmap_zero(ctx->jump_whitelist, ctx->jump_whitelist_cmds); return; } -- 2.30.2