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register: 0.868
device: 0.865
debug: 0.846
risc-v: 0.844
virtual: 0.843
architecture: 0.840
performance: 0.839
graphic: 0.839
user-level: 0.834
assembly: 0.829
permissions: 0.826
socket: 0.822
PID: 0.812
semantic: 0.808
arm: 0.802
mistranslation: 0.796
ppc: 0.796
kernel: 0.795
TCG: 0.794
boot: 0.794
hypervisor: 0.792
files: 0.791
peripherals: 0.783
network: 0.781
VMM: 0.777
vnc: 0.773
i386: 0.767
KVM: 0.761
x86: 0.746
qemu-system-ppc segfaults with -display sdl
Hello.
I was trying to debug this segfault:
https://lists.nongnu.org/archive/html/qemu-ppc/2019-07/msg00186.html
I recompiled latest qemu from git (commit 0b18cfb8f1828c905139b54c8644b0d8f4aad879 ), using this configure line:
./configure --target-list=i386-softmmu,x86_64-softmmu,ppc-softmmu --audio-drv-list=alsa --disable-werror --extra-cflags="-Og" --enable-debug-tcg
after this I tried original line under gdb, it was still segfaulting:
--------------copy-----------------
gdb ./ppc-softmmu/qemu-system-ppc
GNU gdb (GDB) 7.11.1
Copyright (C) 2016 Free Software Foundation, Inc.
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For help, type "help".
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Reading symbols from ./ppc-softmmu/qemu-system-ppc...done.
warning: File "/dev/shm/qemu/.gdbinit" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
To enable execution of this file add
add-auto-load-safe-path /dev/shm/qemu/.gdbinit
line to your configuration file "/home/guest/.gdbinit".
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set auto-load safe-path /
line to your configuration file "/home/guest/.gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual. E.g., run from the shell:
info "(gdb)Auto-loading safe path"
(gdb) run -M mac99,via=pmu -L ../queue-vga/pc-bios -cdrom /mnt/sdb1/PPC-img/lubuntu-16.04-desktop-powerpc.iso -m 512 -display sdl,gl=on -vga std -d guest_errors,unimp -boot d -cpu G4 -g 1024x768x24 -device ES1370
Starting program: /dev/shm/qemu/ppc-softmmu/qemu-system-ppc -M mac99,via=pmu -L ../queue-vga/pc-bios -cdrom /mnt/sdb1/PPC-img/lubuntu-16.04-desktop-powerpc.iso -m 512 -display sdl,gl=on -vga std -d guest_errors,unimp -boot d -cpu G4 -g 1024x768x24 -device ES1370
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/libthread_db.so.1".
[New Thread 0xf560cb40 (LWP 8100)]
[New Thread 0xf4c1ab40 (LWP 8101)]
[New Thread 0xec1b7b40 (LWP 8102)]
[New Thread 0xc5821b40 (LWP 8104)]
[Thread 0xf4c1ab40 (LWP 8101) exited]
[New Thread 0xf4c1ab40 (LWP 8119)]
Thread 4 "qemu-system-ppc" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xec1b7b40 (LWP 8102)]
0xf26c2e44 in code_gen_buffer ()
(gdb) bt full
#0 0xffffffff in code_gen_buffer ()
#1 0x56710cf6 in cpu_exec (itb=<optimized out>, cpu=<optimized out>) at /dev/shm/qemu/accel/tcg/cpu-exec.c:173
env = <optimized out>
ret = <optimized out>
last_tb = <optimized out>
tb_exit = <optimized out>
tb_ptr = 0xf26c2cc0 <code_gen_buffer+103976094> "‹]ш…Ы\017ЊБ\020"
ret = 0
insns_left = <optimized out>
cflags = <optimized out>
tb = 0x5722fe58
last_tb = <optimized out>
tb_exit = <optimized out>
cc = <optimized out>
__func__ = "cpu_exec"
ret = <optimized out>
sc = <optimized out>
#2 0x56710cf6 in cpu_exec (tb_exit=<synthetic pointer>, last_tb=<synthetic pointer>, tb=<optimized out>, cpu=<optimized out>) at /dev/shm/qemu/accel/tcg/cpu-exec.c:621
ret = 0
insns_left = <optimized out>
cflags = <optimized out>
tb = 0x5722fe58
last_tb = <optimized out>
tb_exit = <optimized out>
cc = <optimized out>
__func__ = "cpu_exec"
ret = <optimized out>
sc = <optimized out>
#3 0x56710cf6 in cpu_exec (cpu=0x573db8f8) at /dev/shm/qemu/accel/tcg/cpu-exec.c:732
cflags = <optimized out>
tb = 0x5722fe58
last_tb = <optimized out>
tb_exit = <optimized out>
cc = <optimized out>
__func__ = "cpu_exec"
ret = <optimized out>
sc = <optimized out>
#4 0x566cfade in tcg_cpu_exec (cpu=0x573db8f8) at /dev/shm/qemu/cpus.c:1435
ret = <optimized out>
#5 0x566d1e6d in qemu_tcg_rr_cpu_thread_fn (arg=0x573db8f8) at /dev/shm/qemu/cpus.c:1537
r = <optimized out>
cpu = 0x573db8f8
__PRETTY_FUNCTION__ = "qemu_tcg_rr_cpu_thread_fn"
#6 0x56b56fe0 in qemu_thread_start (args=0x57400668) at util/qemu-thread-posix.c:502
__cancel_buf = {__cancel_jmp_buf = {{__cancel_jmp_buf = {1461911128, 1463813736, 1461911128, -333745816, 247778263, 1392237730}, __mask_was_saved = 0}}, __pad = {0xec1b70d0, 0x0, 0x0, 0x0}}
__cancel_routine = 0x56b57040 <qemu_thread_atexit_notify>
__not_first_call = <optimized out>
qemu_thread_args = 0x57400668
start_routine = 0x566d1a30 <qemu_tcg_rr_cpu_thread_fn>
arg = 0x573db8f8
r = <optimized out>
#7 0xffffffff in start_thread () at /lib/libpthread.so.0
#8 0xffffffff in clone () at /lib/libc.so.6
(gdb) quit
A debugging session is active.
Inferior 1 [process 8096] will be killed.
Quit anyway? (y or n) y
--------------copy end----------
But when I take away -display sdl, or replace it with -display gtk - same line was booting to desktop!
Changing cpu to G3 also allowed boot:
./ppc-softmmu/qemu-system-ppc -M mac99,via=pmu -L ../queue-vga/pc-bios -cdrom /mnt/sdb1/PPC-img/lubuntu-16.04-desktop-powerpc.iso -m 512 -display sdl -vga std -d guest_errors,unimp -boot d -cpu G3 -g 1024x768x24 -device ES1370
This is 32-bit qemu complied with Slackware's gcc 5.5.0.
64-bit qemu works fine.
Works for me with a 32-bit install of fedora 30.
That's using gcc 9.1.1.
Is building with -Og required to reproduce this?
If so, I'm thinking compiler bug...
Hello, Richard!
No, same bug was biting me without any specific options, i tried to add -Og for better debugging, but backtrace was anyway not complete ... I think I can live with -display gtk workaround for now.
I think this one is fixed, I can boot Lubuntu to desktop like this:
qemu-system-ppc -cdrom /dev/shm/lubuntu-16.04-desktop-powerpc.iso -boot d -display sdl,gl=on -g 1024x768x32 -M mac99,via=pmu -cpu G4 -device ES1370 -m 2047 -accel tcg,tb-size=384 -device usb-mouse
without any crash, tried few times.
Note, tb-size seems to be important on 32-bit host now, near qemu 5.0.
qemu-system-ppc --version
QEMU emulator version 4.2.91 (v5.0.0-rc1-dirty)
Copyright (c) 2003-2020 Fabrice Bellard and the QEMU Project developers
-dirty probably because I reinstalled SDL2 (2.0.9- > 2.0.12 during compilation of qemu). I also have different glibc this time (2.30 instead of 2.23)
Andrew Randrianasulu <email address hidden> writes:
> I think this one is fixed, I can boot Lubuntu to desktop like this:
>
> qemu-system-ppc -cdrom /dev/shm/lubuntu-16.04-desktop-powerpc.iso -boot
> d -display sdl,gl=on -g 1024x768x32 -M mac99,via=pmu -cpu G4 -device
> ES1370 -m 2047 -accel tcg,tb-size=384 -device usb-mouse
>
> without any crash, tried few times.
>
> Note, tb-size seems to be important on 32-bit host now, near qemu 5.0.
There were changes this cycle to remove the TB size heuristic based on
guest RAM size. System emulation of 64 bit hosts gets a generous 1gb per
system by default where-as 32 bit hosts make do with a smaller code
buffer (which is statically allocated for user-mode).
See the commits around 600e17b2615 (pull-tcg-20200228)
>
> qemu-system-ppc --version
> QEMU emulator version 4.2.91 (v5.0.0-rc1-dirty)
> Copyright (c) 2003-2020 Fabrice Bellard and the QEMU Project developers
>
> -dirty probably because I reinstalled SDL2 (2.0.9- > 2.0.12 during
> compilation of qemu). I also have different glibc this time (2.30
> instead of 2.23)
--
Alex Bennée
Closing according to comment #3
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