Red Hat Bugzilla – Bug 176935
NPTL: Error checking in sched_setscheduler
Last modified: 2013-03-06 00:59:22 EST
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; fr; rv:1.7.8) Gecko/20050524 Fedora/1.0.4-4 Firefox/1.0.4 Description of problem: OPTS test: sched_setscheduler/19-5.c Tests that an invalid policy cannot be passed to sched_setscheduler. Details are available at: http://nptl.bullopensource.org/Tests/results/report.php Browse: (TC2) 2xi686HT - RHAS4u2 Run 1,2,3 See: http://nptl.bullopensource.org/Tests/results/detailed.php?run_id=12&testcase_id=3619 Version-Release number of selected component (if applicable): Unmodified RHEL4u2 How reproducible: Always Steps to Reproduce: Use OPTS. (Used version was: OPTS cvs repository on Nov 14, 2005) Actual Results: See: http://nptl.bullopensource.org/Tests/results/detailed.php?run_id=12&testcase_id=3619 Additional info:
The test certainly goes beyond what the standard requires, nobody says that policy number is invalid. Reassigning to kernel, as glibc sched_setscheduler is just trivial wrapper around kernel syscall. And on Linux, policy < 0 means "use the previous policy". If you pass 136 as policy value, it will certainly fail: if (policy < 0) policy = oldpolicy = p->policy; else { retval = -EINVAL; if (policy != SCHED_FIFO && policy != SCHED_RR && policy != SCHED_NORMAL) goto out_unlock; }
Use the 3 (correct !) URLS: http://nptl.bullopensource.org/Tests/TC2/report.php#problems http://nptl.bullopensource.org/Tests/results/run-browse.php Click the "Browse" button of : (TC2) 2xi686HT - RHAS4u2 Run 3 You can also select 2 runs and click the "Compare Selected" button.
yes, setcheduler() treats negative values as 'use current policy', but that is used to implement sys_sched_setparam(), see: asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) { return setscheduler(pid, -1, param); } I tend to agree that any invalid value for sched_setscheduler should return -EINVAL. The manpage has: EINVAL The scheduling policy is not one of the recognized policies, or the parameter p does not make sense for the policy. Therefore, i think the kernel should be changed as follows: --- linux-2.6.9/kernel/sched.c.bak 2006-01-16 15:07:05.000000000 -0500 +++ linux-2.6.9/kernel/sched.c 2006-01-16 15:08:32.000000000 -0500 @@ -3406,6 +3406,10 @@ out_nounlock: asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) { + /* negative values for policy are not valid */ + if (policy < 0) + return -EINVAL; + return setscheduler(pid, policy, param); }
Yes, the patch is correct and necessary. This is a "shall" error which must be reported.
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