[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH] fix SMB-related lockup on some systems
From: |
Jörg Walter |
Subject: |
[Qemu-devel] [PATCH] fix SMB-related lockup on some systems |
Date: |
Mon, 27 Aug 2007 10:40:47 +0200 |
User-agent: |
KMail/1.9.7 |
Hi!
I have found a bug where qemu would sit in an endless loop whenever "-smb" was
enabled and accessed. It is probably the same problem some people in the user
forums talk about, and here's my analysis and fix:
On glibc systems with NPTL, fork() is not atomic with regard to signals, while
on non-NPTL-systems, it is. This behaviour is considered to be correct by the
libc developers, as no relevant spec forbids this behaviour.
See this thread for details:
http://sourceware.org/ml/libc-hacker/2007-02/msg00009.html
In qemu, accessing the SMB ip-address causes the slirp code to issue a fork in
slirp/misc.c, which hangs, as we are in mid-emulation and SIGALARM signals
come in at a high rate, probably triggering the above mentioned behaviour.
This patch solves the problem by temporarily blocking all signals until the
fork is over. It doesn't unblock signals in the child, as I assume that
executing the server program will care for that anyways. It works for me,
finally I can access "-smb"-folders again.
--
CU
Jörg
qemu.diff
Description: Text Data
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- [Qemu-devel] [PATCH] fix SMB-related lockup on some systems,
Jörg Walter <=