user-level: 0.923
x86: 0.778
graphic: 0.619
device: 0.618
architecture: 0.609
semantic: 0.533
performance: 0.518
ppc: 0.385
boot: 0.358
network: 0.350
permissions: 0.344
assembly: 0.337
socket: 0.330
mistranslation: 0.286
debug: 0.273
PID: 0.265
i386: 0.264
register: 0.239
vnc: 0.230
peripherals: 0.220
VMM: 0.191
virtual: 0.185
risc-v: 0.175
arm: 0.163
files: 0.148
KVM: 0.119
hypervisor: 0.104
kernel: 0.103
TCG: 0.095
--------------------
user-level: 0.989
virtual: 0.820
debug: 0.406
arm: 0.100
architecture: 0.047
performance: 0.039
TCG: 0.024
files: 0.021
register: 0.015
PID: 0.009
semantic: 0.006
network: 0.006
device: 0.004
hypervisor: 0.004
assembly: 0.004
boot: 0.003
socket: 0.002
VMM: 0.002
kernel: 0.002
risc-v: 0.002
peripherals: 0.001
permissions: 0.001
ppc: 0.001
x86: 0.001
KVM: 0.001
vnc: 0.001
graphic: 0.000
mistranslation: 0.000
i386: 0.000

User mode qemu-aarch: SIGGSEGV signal handler works wrong

I have a user mode qemu-aarch issue. Program with SIGSEGV signal handler works wrong under qemu-aarch: 
once the progam handles the SEGV signal, qemu marks the program's page protected, and signal handler gets SEGV on each subsequent memory access instruction within a program.

The issue is reproduced on WSL Ubuntu 20.04 under Windows 10, qemu-aarch64 version 5.1.50
The issue is also reproducible on the latest upstream qemu-aarch build.

The following workaround disables mprotect call and fixes the issue: https://github.com/BorisUlasevich/qemu/commit/3063d9a64f8395185d65c6b6710d28ee92cd8be5

The issue can be reproduced on OpenJDK which reports SIGSEGV immediately after start. The small reproducer program is attached.



The patch is most definitely wrong.  The page protection
is required to implement self-modifying code, of which a
signal trampoline is a subset.

Moreover, your test case works for me using both
x86_64-linux and aarch64-linux as hosts.

There may be a bug, but I suspect it to be within WSL.
I have no way to test that one way or another.

[Expired for QEMU because there has been no activity for 60 days.]