Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [Regression] 2.6.24-git9: RT sched mishandles artswrapper (bisected) | Date | Sat, 2 Feb 2008 00:39:58 +0100 |
| |
On Friday, 1 of February 2008, Peter Zijlstra wrote: > > On Fri, 2008-02-01 at 12:50 +0100, Rafael J. Wysocki wrote: > > On Friday, 1 of February 2008, Peter Zijlstra wrote: > > > > > It arts run as root, or does it use RLIMIT_RTPRIO to allow users to > > > > execute realtime tasks? > > > > artswrapper is setuid root and RLIMIT_RTPRIO is apparently not used. > > Still, artswrapper is running as a regular user, so it most probably drops > > privileges early. > > > > BTW, it fails while running the artsmessage utility used for displaying arts > > error messages, so I guess there's an error in arts that this thing tries to > > display and deadlocks (or something like that). > > > > Should I test the patch nevertheless? > > Don't think that would help any in this situation. The thing to look out > for are RT tasks running with a different uid than 0. > > This patch would only stop a task from obtaining RT class scheduling > when already in a (misconfigured) group. If the task is RT and then > switches group another - similar - thing is needed. > > Does this artsmessage thing also run with RT priority?
Well, it's in a strange state (after it's broken). From top:
PR = -51 NI = 0 S = R %CPU = 0.0 %MEM = 0.0
Here's the corresponding trace from sysrq+t:
artswrapper R running task 5128 5776 1 ffff81007a8dbd88 0000000000000046 000000015c4321b0 ffff81006aa6e5c8 ffffffff806daa00 ffffffff806daa00 ffffffff806daa00 ffffffff806daa00 ffffffff806daa00 ffffffff806daa00 ffffffff806d7a60 ffffffff806daa00 Call Trace: [<ffffffff8022fdb7>] ? try_to_wake_up+0x77/0x200 [<ffffffff8023573d>] __cond_resched+0x2d/0x60 [<ffffffff804ddce1>] _cond_resched+0x31/0x40 [<ffffffff804ddd24>] wait_for_common+0x34/0x170 [<ffffffff8022fdb7>] ? try_to_wake_up+0x77/0x200 [<ffffffff804ddec8>] wait_for_completion+0x18/0x20 [<ffffffff80235aba>] sched_exec+0xba/0xf0 [<ffffffff802b5a64>] do_execve+0x64/0x220 [<ffffffff802097c6>] sys_execve+0x46/0x70 [<ffffffff8020bab7>] stub_execve+0x67/0xb0
| |