From: Andrew Morton Date: Fri, 24 Mar 2006 11:18:35 +0000 (-0800) Subject: [PATCH] RLIMIT_CPU: fix handling of a zero limit X-Git-Tag: v2.6.17-rc1~875 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e0661111e5441995f7a69dc4336c9f131cb9bc58;p=linux-2.6 [PATCH] RLIMIT_CPU: fix handling of a zero limit At present the kernel doesn't honour an attempt to set RLIMIT_CPU to zero seconds. But the spec says it should, and that's what 2.4.x does. Fixing this for real would involve some complexity (such as adding a new it-has-been-set flag to the task_struct, and testing that everwhere, instead of overloading the value of it_prof_expires). Given that a 2.4 kernel won't actually send the signal until one second has expired anyway, let's just handle this case by treating the caller's zero-seconds as one second. Cc: Martin Schwidefsky Cc: Ulrich Weigand Cc: Cliff Wickman Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/sys.c b/kernel/sys.c index 9bdf94f3ae..9e157e0240 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1661,8 +1661,19 @@ asmlinkage long sys_setrlimit(unsigned int resource, struct rlimit __user *rlim) it_prof_secs = cputime_to_secs(current->signal->it_prof_expires); if (it_prof_secs == 0 || new_rlim.rlim_cur <= it_prof_secs) { - cputime_t cputime = secs_to_cputime(new_rlim.rlim_cur); + unsigned long rlim_cur = new_rlim.rlim_cur; + cputime_t cputime; + if (rlim_cur == 0) { + /* + * The caller is asking for an immediate RLIMIT_CPU + * expiry. But we use the zero value to mean "it was + * never set". So let's cheat and make it one second + * instead + */ + rlim_cur = 1; + } + cputime = secs_to_cputime(rlim_cur); read_lock(&tasklist_lock); spin_lock_irq(¤t->sighand->siglock); set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);