aarch64/risvc64 qemu emulation -static-pie alpine linux getrandom() error #22981
Description
qBittorrent & operating system versions
qBittorrent: 5.1.2
Linux/Debian/Alpine
Qt: 6.91
libtorrent-rasterbar: 2.0.11
What is the problem?
The introduction of this -static-pie patch in Alpine(edge) gcc master here has exposed a problem with qemu when I built a fully static binary.
note: The binary works fine on the native target but when emulated via qemu it has the getrandom() error. So not sure if this a qemu specific thing with a static-pie binary.
qbittorrent-nox: ELF 64-bit LSB pie executable, UCB RISC-V, RVC, double-float ABI, version 1 (SYSV), static-pie linked, stripped
Here is the qemu gdbbacktrace.
Reading symbols from ./qbittorrent-nox-dbg...
(gdb) set architecture riscv:rv64
The target architecture is set to "riscv:rv64".
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
Reading /usr/lib/debug/.build-id/ad/45634e474aaba0a3571af5f6d6d350a091b1b6.debug from remote target...
warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
0x00005555559bad6a in _start ()
(gdb) break main
Breakpoint 1 at 0x5555559fa1e4: file /root/qbt-build/qBittorrent-release-5.1.2/src/app/main.cpp, line 175.
(gdb) continue
Continuing.
Breakpoint 1, main (argc=1, argv=0x7cc3ffb12dc8) at /root/qbt-build/qBittorrent-release-5.1.2/src/app/main.cpp:175
warning: 175 /root/qbt-build/qBittorrent-release-5.1.2/src/app/main.cpp: No such file or directory
(gdb) continue
Continuing.
Program received signal SIGABRT, Aborted.
0x0000555556b9d4c6 in __restore_sigs ()
(gdb) bt
#0 0x0000555556b9d4c6 in __restore_sigs ()
#1 0x0000555556b9d50e in raise ()
#2 0x0000555556b948ba in abort ()
#3 0x000055555695fe84 in qAbort () at /root/qbt-build/qtbase/src/corelib/global/qassert.cpp:46
#4 0x0000555556961b9c in qt_message_fatal<QString&> (context=..., message=...) at /root/qbt-build/qtbase/src/corelib/global/qlogging.cpp:2149
#5 0x00005555569624f4 in qt_message (msgType=msgType@entry=QtFatalMsg, context=..., msg=msg@entry=0x5555572d24f0 "getrandom() error. Reason: \"%s\". Error code: %d.", ap=ap@entry=0x7cc3ffb12660) at /root/qbt-build/qtbase/src/corelib/global/qlogging.cpp:381
#6 0x00005555569628aa in QMessageLogger::fatal (this=0x7cc3ffb126a8, msg=0x5555572d24f0 "getrandom() error. Reason: \"%s\". Error code: %d.") at /root/qbt-build/qtbase/src/corelib/global/qlogging.cpp:883
#7 0x0000555555cbba10 in (anonymous namespace)::RandomLayer::RandomLayer (this=0x555558018cd0 <Utils::Random::rand(unsigned int, unsigned int)::layer>) at /root/qbt-build/qBittorrent-release-5.1.2/src/base/utils/randomlayer_linux.cpp:60
#8 0x0000555555cbbd4c in Utils::Random::rand (min=1024, max=65535) at /root/qbt-build/qBittorrent-release-5.1.2/src/base/utils/random.cpp:45
#9 0x0000555555ab743c in BitTorrent::SessionImpl::SessionImpl (this=0x7cc3ff117020, parent=0x0) at /root/qbt-build/qBittorrent-release-5.1.2/src/base/bittorrent/sessionimpl.cpp:553
#10 0x0000555555ab29f2 in BitTorrent::Session::initInstance () at /root/qbt-build/qBittorrent-release-5.1.2/src/base/bittorrent/sessionimpl.cpp:342
#11 0x00005555559c9734 in Application::exec (this=0x7cc400166010) at /root/qbt-build/qBittorrent-release-5.1.2/src/app/application.cpp:852
#12 0x00005555559face8 in main (argc=1, argv=0x7cc3ffb12dc8) at /root/qbt-build/qBittorrent-release-5.1.2/src/app/main.cpp:328
(gdb)Steps to reproduce
Not sure how to reproduce this as it need a fully static binary using the alpine gcc that is patched for static-pie. Hopefully the backtrace and patch is enough.
if i clear settings
rm -rf .config/qBittorrent/ .local/share/qBittorrent/The start binary and press enter i will see
No further notices will be issued.
Press 'Enter' key to continue...
WebUI will be started shortly after internal preparations. Please wait...
getrandom() error. Reason: "Bad address". Error code: 14.
qemu: uncaught target signal 6 (Aborted) - core dumped
AbortedAdditional context
I used co-pilot to debug the backtrace and create a patch that worked to solve the problem and allow the binary to run via emulation.
Not advocating you use this patch, just that as a proof of concept it fixed the problem. So made the issue for you to access.
--- qBittorrent/src/base/utils/randomlayer_linux.cpp 2025-07-12 01:06:00.000004109 +0100
+++ randomlayer_linux.cpp 2025-07-12 01:05:21.889222100 +0100
@@ -30,10 +30,12 @@
#include <cstdio>
#include <cstring>
#include <limits>
+#include <memory>
#include <sys/random.h>
#include <QtLogging>
+#include <QFile>
namespace
{
@@ -45,27 +47,24 @@
RandomLayer()
{
- if (::getrandom(nullptr, 0, 0) < 0)
- {
- if (errno == ENOSYS)
- {
- // underlying kernel does not implement this system call
- // fallback to `urandom`
- m_randDev = fopen("/dev/urandom", "rb");
- if (!m_randDev)
- qFatal("Failed to open /dev/urandom. Reason: \"%s\". Error code: %d.", std::strerror(errno), errno);
- }
- else
- {
- qFatal("getrandom() error. Reason: \"%s\". Error code: %d.", std::strerror(errno), errno);
+ if (::getrandom(nullptr, 0, GRND_NONBLOCK) == -1) {
+ if (errno == ENOSYS || errno == EFAULT) {
+ // Fallback to /dev/urandom for QEMU compatibility
+ m_randDev = std::fopen("/dev/urandom", "rb");
+ if (!m_randDev) {
+ qFatal("Failed to open /dev/urandom");
+ }
+ return;
}
+
+ qFatal("getrandom() error. Reason: \"%s\". Error code: %d.", std::strerror(errno), errno);
}
}
~RandomLayer()
{
if (m_randDev)
- fclose(m_randDev);
+ std::fclose(m_randDev);
}
static constexpr result_type min()
@@ -107,12 +106,12 @@
result_type getRandomViaFile() const
{
result_type buf = 0;
- if (fread(&buf, sizeof(buf), 1, m_randDev) == 1)
+ if (std::fread(&buf, sizeof(buf), 1, m_randDev) == 1)
return buf;
qFatal("Read /dev/urandom error. Reason: \"%s\". Error code: %d.", std::strerror(errno), errno);
}
- FILE *m_randDev = nullptr;
+ std::FILE *m_randDev = nullptr;
};
}
Log(s) & preferences file(s)
n/a