Package: libserial1
Version: 1.0.0-9+b2
Severity: normal
Tags: patch upstream
Dear Maintainer,
when writing data to a serial port, occasional exception "Interrupted system
call"
is thrown by libserial. This is because there is no retry in case a call to
tcdrain
returns EINTR.
The bug was reported upstream:
https://github.com/crayzeewulf/libserial/issues/194
A pull request was also submitted:
https://github.com/crayzeewulf/libserial/pull/195
The proposed fix was tested in a special setup where data was continuosly
written
to the serial port through libserial and at the same time repeated systemcalls
via
sysfs were made. Without the change the exception could be easily reproduced,
after
the proposed change it did not occur anymore for several days.
I ask you to include this patch in Debian as I don't expect a new upstream
release
for this.
Thanks,
Tobias
-- System Information:
Debian Release: trixie/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: arm64, armhf
Kernel: Linux 6.12.11-amd64 (SMP w/10 CPU threads; PREEMPT)
Kernel taint flags: TAINT_SOFTLOCKUP
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8),
LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages libserial1 depends on:
ii libc6 2.41-6
ii libgcc-s1 14.2.0-19
ii libstdc++6 14.2.0-19
libserial1 recommends no packages.
libserial1 suggests no packages.
-- no debconf information
From: Tobias Graemer <tobias.grae...@mt.com>
Date: Thu, 10 Apr 2025 10:31:17 +0200
Subject: [PATCH] Call tcdrain with retry
When writing to the serial port, exception "interrupted system call"
was observed. System calls that are interrupted shall be repeated, as
explained in the description of call_with_retry() template function.
---
src/SerialPort.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/SerialPort.cpp b/src/SerialPort.cpp
index e354fcb..b5b4d12 100644
--- a/src/SerialPort.cpp
+++ b/src/SerialPort.cpp
@@ -922,7 +922,7 @@ namespace LibSerial
throw NotOpen(ERR_MSG_PORT_NOT_OPEN) ;
}
- if (tcdrain(this->mFileDescriptor) < 0)
+ if (call_with_retry(tcdrain, this->mFileDescriptor) < 0)
{
throw std::runtime_error(std::strerror(errno)) ;
}
