tree 96d34b10d000fa8b1df16ae8f4c73761013371b5
parent fc00a6274b786f6863b32c79ff6f92aa0960b789
author Andreas Steinmetz <[EMAIL PROTECTED]> Sat, 23 Jul 2005 13:42:04 +0200
committer Linus Torvalds <[EMAIL PROTECTED]> Wed, 27 Jul 2005 05:30:51 -0700
[PATCH] Fix RLIMIT_RTPRIO breakage
RLIMIT_RTPRIO is supposed to grant non privileged users the right to use
SCHED_FIFO/SCHED_RR scheduling policies with priorites bounded by the
RLIMIT_RTPRIO value via sched_setscheduler(). This is usually used by
audio users.
Unfortunately this is broken in 2.6.13rc3 as you can see in the excerpt
from sched_setscheduler below:
/*
* Allow unprivileged RT tasks to decrease priority:
*/
if (!capable(CAP_SYS_NICE)) {
/* can't change policy */
if (policy != p->policy)
return -EPERM;
After the above unconditional test which causes sched_setscheduler to
fail with no regard to the RLIMIT_RTPRIO value the following check is made:
/* can't increase priority */
if (policy != SCHED_NORMAL &&
param->sched_priority > p->rt_priority &&
param->sched_priority >
p->signal->rlim[RLIMIT_RTPRIO].rlim_cur)
return -EPERM;
Thus I do believe that the RLIMIT_RTPRIO value must be taken into
account for the policy check, especially as the RLIMIT_RTPRIO limit is
of no use without this change.
The attached patch fixes this problem.
Signed-off-by: Andreas Steinmetz <[EMAIL PROTECTED]>
Acked-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
kernel/sched.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/sched.c b/kernel/sched.c
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3528,7 +3528,8 @@ recheck:
*/
if (!capable(CAP_SYS_NICE)) {
/* can't change policy */
- if (policy != p->policy)
+ if (policy != p->policy &&
+ !p->signal->rlim[RLIMIT_RTPRIO].rlim_cur)
return -EPERM;
/* can't increase priority */
if (policy != SCHED_NORMAL &&
-
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