From: Thomas Huth <1878501@bugs.launchpad.net>
To: qemu-devel@nongnu.org
Subject: [Bug 1878501] Re: qemu-i386 does not define AT_SYSINFO
Date: Tue, 11 May 2021 05:03:45 -0000 [thread overview]
Message-ID: <162070942570.6707.17748030357064385858.malone@gac.canonical.com> (raw)
In-Reply-To: 158941344748.31408.6066832909673515633.malonedeb@chaenomeles.canonical.com
The QEMU project is currently moving its bug tracking to another system.
For this we need to know which bugs are still valid and which could be
closed already. Thus we are setting the bug state to "Incomplete" now.
If the bug has already been fixed in the latest upstream version of QEMU,
then please close this ticket as "Fix released".
If it is not fixed yet and you think that this bug report here is still
valid, then you have two options:
1) If you already have an account on gitlab.com, please open a new ticket
for this problem in our new tracker here:
https://gitlab.com/qemu-project/qemu/-/issues
and then close this ticket here on Launchpad (or let it expire auto-
matically after 60 days). Please mention the URL of this bug ticket on
Launchpad in the new ticket on GitLab.
2) If you don't have an account on gitlab.com and don't intend to get
one, but still would like to keep this ticket opened, then please switch
the state back to "New" or "Confirmed" within the next 60 days (other-
wise it will get closed as "Expired"). We will then eventually migrate
the ticket automatically to the new system (but you won't be the reporter
of the bug in the new system and thus you won't get notified on changes
anymore).
Thank you and sorry for the inconvenience.
** Changed in: qemu
Status: New => Incomplete
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https://bugs.launchpad.net/bugs/1878501
Title:
qemu-i386 does not define AT_SYSINFO
Status in QEMU:
Incomplete
Bug description:
qemu-i386 does not define the AT_SYSINFO auxval when running i386
Linux binaries.
On most libcs, this is properly handled, but this is mandatory for the
i686 Bionic (Android) libc or it will segfault.
This is due to a blind assumption that getauxval(AT_SYSINFO) will
return a valid function pointer:
The code varies from version to version, but it looks like this:
void *__libc_sysinfo;
// mangled as _Z19__libc_init_sysinfov
void __libc_init_sysinfo() {
bool dummy;
// __bionic_getauxval = getauxval
__libc_sysinfo = reinterpret_cast<void *>(__bionic_getauxval(AT_SYSINFO, dummy));
}
A simple way to reproduce is to compile a basic C program against the
NDK:
int main(void) { return 0; }
$ i686-linux-android-clang -static empty.c -o empty
$ qemu-i386 -cpu max ./empty
qemu: uncaught target signal 11 (Segmentation fault) - core dumped
Segmentation fault
The place where it segfaults is misleading: It will, at least on the
current NDK, crash on __set_thread_area, this is due to it calling a
function pointer to __libc_sysinfo returned by __kernel_syscall.
QEMU 4.1.1 (aarch64)
Pixel 2 XL via Termux
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next prev parent reply other threads:[~2021-05-11 5:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 23:44 [Bug 1878501] [NEW] qemu-i386 does not define AT_SYSINFO easyaspi314
2020-05-14 7:45 ` [Bug 1878501] " Laurent Vivier
2020-05-14 15:31 ` Richard Henderson
2021-05-11 5:03 ` Thomas Huth [this message]
2021-07-11 4:17 ` Launchpad Bug Tracker
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