From: Roland Scheidegger Date: Wed, 4 Jul 2018 02:44:17 +0000 (+0200) Subject: r600/sb: fix crash in fold_alu_op3 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=817efd89685efc6b5866e09cbdad01c4ff21c737;p=mesa.git r600/sb: fix crash in fold_alu_op3 fold_assoc() called from fold_alu_op3() can lower the number of src to 2, which then leads to an invalid access to n.src[2]->gvalue(). This didn't seem to have caused much harm in the past, but on Fedora 28 it will crash (presumably because -D_GLIBCXX_ASSERTIONS is used, although with libstdc++ 4.8.5 this didn't do anything, -D_GLIBCXX_DEBUG was needed to show the issue). An alternative fix would be to instead call fold_alu_op2() from within fold_assoc() when the number of src is reduced and return always TRUE from fold_assoc() in this case, with the only actual difference being the return value from fold_alu_op3() then. I'm not sure what the return value actually should be in this case (or whether it even can make a difference). https://bugs.freedesktop.org/show_bug.cgi?id=106928 Cc: mesa-stable@lists.freedesktop.org Reviewed-by: Dave Airlie --- diff --git a/src/gallium/drivers/r600/sb/sb_expr.cpp b/src/gallium/drivers/r600/sb/sb_expr.cpp index 1df78da6608..ad798453bc1 100644 --- a/src/gallium/drivers/r600/sb/sb_expr.cpp +++ b/src/gallium/drivers/r600/sb/sb_expr.cpp @@ -945,6 +945,8 @@ bool expr_handler::fold_alu_op3(alu_node& n) { if (!sh.safe_math && (n.bc.op_ptr->flags & AF_M_ASSOC)) { if (fold_assoc(&n)) return true; + if (n.src.size() < 3) + return fold_alu_op2(n); } value* v0 = n.src[0]->gvalue();