linux/kernel/sched
Juri Lelli b0827819b0 sched/deadline: Restrict user params max value to 2^63 ns
Michael Kerrisk noticed that creating SCHED_DEADLINE reservations
with certain parameters (e.g, a runtime of something near 2^64 ns)
can cause a system freeze for some amount of time.

The problem is that in the interface we have

 u64 sched_runtime;

while internally we need to have a signed runtime (to cope with
budget overruns)

 s64 runtime;

At the time we setup a new dl_entity we copy the first value in
the second. The cast turns out with negative values when
sched_runtime is too big, and this causes the scheduler to go crazy
right from the start.

Moreover, considering how we deal with deadlines wraparound

 (s64)(a - b) < 0

we also have to restrict acceptable values for sched_{deadline,period}.

This patch fixes the thing checking that user parameters are always
below 2^63 ns (still large enough for everyone).

It also rewrites other conditions that we check, since in
__checkparam_dl we don't have to deal with deadline wraparounds
and what we have now erroneously fails when the difference between
values is too big.

Reported-by: Michael Kerrisk <mtk.manpages@gmail.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Dario Faggioli<raistlin@linux.it>
Cc: Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140513141131.20d944f81633ee937f256385@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-22 10:21:27 +02:00
..
auto_group.c sched: Replace hardcoding of -20 and 19 with MIN_NICE and MAX_NICE 2014-02-22 18:15:54 +01:00
auto_group.h Revert "sched/autogroup: Fix crash on reboot when autogroup is disabled" 2012-12-11 10:23:45 +01:00
clock.c kernel: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:36:11 -07:00
completion.c sched: Move completion code from core.c to completion.c 2013-11-06 07:49:19 +01:00
core.c sched/deadline: Restrict user params max value to 2^63 ns 2014-05-22 10:21:27 +02:00
cpuacct.c cgroup: clean up cgroup_subsys names and initialization 2014-02-08 10:36:58 -05:00
cpuacct.h sched/cpuacct: Initialize root cpuacct earlier 2013-04-10 13:54:20 +02:00
cpudeadline.c sched/deadline: Fix memory leak 2014-05-07 11:51:32 +02:00
cpudeadline.h sched/deadline: speed up SCHED_DEADLINE pushes with a push-heap 2014-01-13 13:46:46 +01:00
cpupri.c sched: Use CPUPRI_NR_PRIORITIES instead of MAX_RT_PRIO in cpupri check 2014-05-07 11:51:33 +02:00
cpupri.h
cputime.c sched: Sanitize irq accounting madness 2014-05-07 11:51:30 +02:00
deadline.c sched/deadline: Fix sched_yield() behavior 2014-05-07 11:51:31 +02:00
debug.c Merge branch 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-04-03 13:05:42 -07:00
fair.c sched: Fix updating rq->max_idle_balance_cost and rq->next_balance in idle_balance() 2014-05-07 11:51:36 +02:00
features.h sched/numa: Resist moving tasks towards nodes with fewer hinting faults 2013-10-09 12:40:27 +02:00
idle_task.c sched/fair: Push down check for high priority class task into idle_balance() 2014-03-11 12:05:37 +01:00
idle.c sched/idle: Add more comments to the code 2014-03-11 11:52:49 +01:00
Makefile sched/idle: Move cpu/idle.c to sched/idle.c 2014-02-11 09:58:30 +01:00
proc.c sched: Change get_rq_runnable_load() to static and inline 2013-06-27 10:07:44 +02:00
rt.c sched: Check for stop task appearance when balancing happens 2014-04-17 13:39:51 +02:00
sched.h sched/numa: Fix task_numa_free() lockdep splat 2014-04-11 10:39:15 +02:00
stats.c kernel: audit/fix non-modular users of module_init in core code 2014-04-03 16:21:07 -07:00
stats.h sched: Micro-optimize by dropping unnecessary task_rq() calls 2013-09-25 13:51:06 +02:00
stop_task.c sched: Fix hotplug task migration 2014-02-21 21:43:18 +01:00
wait.c sched: Move wait code from core.c to wait.c 2013-11-06 07:49:18 +01:00