Yeah, QEMU crashing is definitely a bug that we should fix. (NB that it's not a 'security' bug, though -- we make no guarantee that malicious code run under QEMU with TCG emulation is unable to escape from it: there's too much unaudited and old code for us to be able to safely make that guarantee.)
-- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1663287 Title: Illegal delay slot code causes abort on mips64 Status in QEMU: New Bug description: During some randomised testing of an experimental MIPS implementation I found an instruction sequence that also causes aborts on mainline qemu's MIPS support. The problem is triggered by an MSA branch instruction appearing in a delay slot when emulating a processor without MSA support. For example, with the current repository HEAD (f073cd3a2bf1054135271b837c58a7da650dd84b) configured for mips64-softmmu, if I run the attached binary using mips64-softmmu/qemu-system-mips64 -bios ../abort2.bin -machine mipssim -nographic it will report unknown branch 0x13000 Aborted (core dumped) The binary contains the following two instructions: 00200008 jr at 47081e61 bz.b w8,0xffffffffbfc0798c The jr sets up a jump, and hflags is set accordingly in gen_compute_branch (in target/mips/translate.c). When processing the bz.b, check_insn generates an exception because the instruction isn't support, but gen_msa_branch skips the usual delay slot check for the same reason, and sets more bits in hflags, leading to an abort in gen_branch because the hflags are now invalid. I suspect the best fix is to remove the instruction set condition from the delay slot check in gen_msa_branch. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1663287/+subscriptions
