This is necessary for running .net core programs under valgrind which generates a VEX prefixxed JMP rel32 instruction. A prelimenary patch (not accepted upstream yet) is in the valgrind bugzilla: https://bugs.kde.org/show_bug.cgi?id=422174 Note that even with this fix, .net core applications are valgrind "clean", but without this fix .net core just crashes under valgrind.
This is just to get dotnet to start up. Using dotnet from dotnet-sdk-3.1 rpm. Before the fix: $ valgrind -q dotnet --version Will crash with: vex amd64->IR: unhandled instruction bytes: 0x48 0xE9 0x70 0xB3 0x41 0xA9 0x49 0xBA 0x88 0xCD vex amd64->IR: REX=1 REX.W=1 REX.R=0 REX.X=0 REX.B=0 vex amd64->IR: VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=NONE vex amd64->IR: PFX.66=0 PFX.F2=0 PFX.F3=0 After the fix: $ valgrind -q dotnet --version 2>/dev/null 3.1.103 There will still be warnings about Conditional jump or move depends on uninitialised value(s) and syscalls that use bad params.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory (new packages: devtoolset-10-valgrind), and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2020:5287