On Fri, 20 Dec 2002, Sean Kelly wrote: > On my 5.0-CURRENT kernel built 45 minutes ago, I can bring my system to its > knees by doing > > # cat /dev/io > > While I understand that this isn't exactly something one would normally be > doing, is it really something that should bring the system down?
No. Writing to /dev/io is not supported. write(2) to a device that doesn't support writing should return -1 and set errno to ENODEV. This was broken mainly by removing the default case from mem.c:mmrw(). This causes mmrw() to loop endlessly without giving up control. Giant locking in -current makes this especially fatal -- mmrw() holds Giant so even most interrupt handlers are blocked. In RELENG_4 the only bug near here is that mmrw() returns ENXIO instead of ENODEV for writes to /dev/io. Bruce To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-current" in the body of the message
