TCG: 0.966
graphic: 0.872
performance: 0.736
files: 0.714
network: 0.650
device: 0.641
vnc: 0.538
ppc: 0.509
semantic: 0.485
socket: 0.480
kernel: 0.469
risc-v: 0.456
PID: 0.389
boot: 0.361
peripherals: 0.338
i386: 0.330
architecture: 0.288
VMM: 0.288
arm: 0.262
x86: 0.235
KVM: 0.225
register: 0.224
debug: 0.203
permissions: 0.145
mistranslation: 0.118
hypervisor: 0.100
virtual: 0.076
user-level: 0.060
assembly: 0.043
--------------------
TCG: 0.953
kernel: 0.593
files: 0.404
debug: 0.182
x86: 0.147
hypervisor: 0.080
VMM: 0.050
KVM: 0.047
virtual: 0.024
register: 0.019
i386: 0.017
arm: 0.015
risc-v: 0.013
PID: 0.011
ppc: 0.007
network: 0.007
device: 0.005
performance: 0.004
assembly: 0.004
semantic: 0.003
user-level: 0.002
socket: 0.002
vnc: 0.002
peripherals: 0.002
boot: 0.001
architecture: 0.001
graphic: 0.001
permissions: 0.001
mistranslation: 0.000

Unreachable code
Description of problem:
There is always a false condition in the function `alloc_code_gen_buffer_splitwx_memfd` in the file `tcg/region.c`. If `buf_rw == NULL` we go to the mark __fail__:

https://gitlab.com/qemu-project/qemu/-/blob/master/tcg/region.c?ref_type=heads#L580-L583

But the value of `buf_rx` is __`MAP_FAILED`__:

https://gitlab.com/qemu-project/qemu/-/blob/master/tcg/region.c?ref_type=heads#L577

And this line will never be reached:

https://gitlab.com/qemu-project/qemu/-/blob/master/tcg/region.c?ref_type=heads#L601

Found by Linux Verification Center (portal.linuxtesting.ru) with SVACE.

Author A. Voronin.