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Subject[PATCH] saner limit for max_threads
Hi,

by default the limit for max_threads is such that
the system will try to allocate up to half the
physical memory in task_structs.

Because for each 8kB task struct we'll often want
a struct_mm, a page directory, 3 page tables and
some more structures, this means that a fork bomb
will leave the box DEAD with root never ever getting
a chance of using his reserved tasks and killing the
bad user.

The patch below adjusts the max_threads calculation
to something which should be more sane, though quite
possibly still to high...

Please apply for the next -pre kernel.

thanks,

Rik
--
http://www.surriel.com/ http://distro.conectiva.com/


--- linux-2.4.6-pre3/kernel/fork.c.orig Sun Jun 17 20:45:54 2001
+++ linux-2.4.6-pre3/kernel/fork.c Sun Jun 17 23:07:20 2001
@@ -70,7 +70,7 @@
* value: the thread structures can take up at most half
* of memory.
*/
- max_threads = mempages / (THREAD_SIZE/PAGE_SIZE) / 2;
+ max_threads = mempages / (THREAD_SIZE/PAGE_SIZE) / 16;

init_task.rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
init_task.rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
-
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