From: Anton Ivanov
For more details see:
http://stackoverflow.com/questions/4624071/pipe-buffer-size-is-4k-or-64k
The observations on that thread have been confirmed by us for UML's
UBD driver. If you load UML with network IO and do disk IO at the same
time the UBD IO helper thread fails to pro
From: Anton Ivanov
Signed-off-by: Anton Ivanov
---
arch/um/os-Linux/main.c |1 +
1 file changed, 1 insertion(+)
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index 7a86dd5..048166d 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -149,6 +149,7 @@ int
From: Anton Ivanov
The reverse case of this race (you must msync before read) is
well known. This is the not so common one.
It can be triggered only on systems which do a lot of task
switching and only at UML startup. If you are starting 200+ UMLs
~ 0.5% will always die without this fix.
Signed
This bug has been there as far back as 2.6.x... It is known as
"userspace process sits in Z state", occasional hang, etc. It has been
tagged by maintainers as "unreproducible" for 7 odd years now. I agree -
on stock UML it is difficult to reproduce - it may take half a day to
hit it when running a
