Kernel Bug Tracker – Bug 7750
open/close loop causes disabled irq
Last modified: 2008-05-17 15:19:47 UTC
Most recent kernel where this bug did *NOT* occur: unknown (is reproducible with
126.96.36.199 and 2.6.20-rc2)
Hardware Environment: HP nc6000 laptop
A Debian user reported that a simple program that repeatedly opens and closes a
serial device will eventually cause an irq line to be disabled.
Debian report: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=404815
I've also reproduced this on 2.6.20-rc2.
Steps to reproduce:
Run the attached program.
Created attachment 9958 [details]
I tried reproducing this issue and found that the issue is observed when the
PREEMPTION is turned off. If kernel preemption is turned on then the error is
To refresh please test it with recent kernel. Is the problem still there?
I attempted to reproduce this today under 2.6.22 and was unable to. I then used git bisect to try and identify the changeset that fixed the issue and ended up with the one below.
I wonder if this should be considered a security issue (DoS)?
Author: Linus Torvalds <firstname.lastname@example.org>
Date: Tue Jan 23 14:16:31 2007 -0800
Clear spurious irq stat information when adding irq handler
Any newly added irq handler may obviously make any old spurious irq
status invalid, since the new handler may well be the thing that is
supposed to handle any interrupts that came in.
So just clear the statistics when adding handlers.
Pointed-out-by: Alan Cox <email@example.com>
Acked-by: Thomas Gleixner <firstname.lastname@example.org>
Acked-by: Ingo Molnar <email@example.com>
Signed-off-by: Linus Torvalds <firstname.lastname@example.org>
:040000 040000 d3bd3ddf15462bca9f796e899b96f2e17d30bc34 3ea41ebe53747377873202db8b59e2c4e84aef8c M kernel
whee, we fixed one. Thanks.