From: "Andreas K. Hüttel" <1906193@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1906193] Re: riscv32 user mode emulation: fork return values broken
Date: Sat, 05 Dec 2020 01:27:34 -0000 [thread overview]
Message-ID: <160713165467.30106.10281403367680402054.malone@chaenomeles.canonical.com> (raw)
In-Reply-To: 160669515259.21126.12178770886175022752.malonedeb@gac.canonical.com
This is the (statically linked) binary resulting from the source; with
it the problem can be demonstrated "standalone", without any other rv32
libraries or a complete chroot, just running the binary with qemu-
riscv32.
Generated with
(riscv-ilp32 chroot) farino /tmp # gcc -static -o wait-test-short -g
wait-test-short.c
** Attachment added: "wait-test-short"
https://bugs.launchpad.net/qemu/+bug/1906193/+attachment/5441136/+files/wait-test-short
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https://bugs.launchpad.net/bugs/1906193
Title:
riscv32 user mode emulation: fork return values broken
Status in QEMU:
New
Bug description:
When running in a chroot with riscv32 (on x86_64; qemu git master as
of today):
The following short program forks; the child immediately returns with
exit(42). The parent checks for the return value - and obtains 40!
gcc-10.2
===============================================
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/wait.h>
main(c, v)
int c;
char **v;
{
pid_t pid, p;
int s, i, n;
s = 0;
pid = fork();
if (pid == 0)
exit(42);
/* wait for the process */
p = wait(&s);
if (p != pid)
exit (255);
if (WIFEXITED(s))
{
int r=WEXITSTATUS(s);
if (r!=42) {
printf("child wants to return %i (0x%X), parent received %i (0x%X), difference %i\n",42,42,r,r,r-42);
}
}
}
===============================================
(riscv-ilp32 chroot) farino /tmp # ./wait-test-short
child wants to return 42 (0x2A), parent received 40 (0x28), difference -2
===============================================
(riscv-ilp32 chroot) farino /tmp # gcc --version
gcc (Gentoo 10.2.0-r1 p2) 10.2.0
Copyright (C) 2020 Free Software Foundation, Inc.
Dies ist freie Software; die Kopierbedingungen stehen in den Quellen. Es
gibt KEINE Garantie; auch nicht für MARKTGÄNGIGKEIT oder FÜR SPEZIELLE ZWECKE.
(riscv-ilp32 chroot) farino /tmp # ld --version
GNU ld (Gentoo 2.34 p6) 2.34.0
Copyright (C) 2020 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.
To manage notifications about this bug go to:
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next prev parent reply other threads:[~2020-12-05 1:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 0:12 [Bug 1906193] [NEW] riscv32 user mode emulation: fork return values broken Dilfridge
2020-12-05 1:27 ` Andreas K. Hüttel [this message]
2020-12-15 22:06 ` [Bug 1906193] " Andreas K. Hüttel
2020-12-16 20:56 ` Andreas K. Hüttel
2020-12-16 21:05 ` Andreas K. Hüttel
2020-12-19 18:16 ` Alistair Francis
2020-12-19 23:21 ` Andreas K. Hüttel
2020-12-21 13:28 ` Andreas K. Hüttel
2020-12-21 21:44 ` Alistair Francis
2020-12-21 23:11 ` Richard Henderson
2020-12-26 17:53 ` Andreas K. Hüttel
2021-01-15 23:10 ` Alistair Francis
2021-01-16 18:58 ` Andreas K. Hüttel
2021-02-16 20:58 ` Alistair Francis
2021-04-30 8:57 ` Thomas Huth
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