Hi! It seems /bin/sh in 4.8-STABLE has problem with SIGCHLD processing. In short, it often fails to process it correctly, zombies float around, jobs are not marked as finished in jobtab[] that fills memory and takes much CPU to be processed. Run this one-liner using /bin/sh and see hundreds of zombies: #!/bin/sh while :; do : & done A kernel will halt this as soon as it reaches limits and write a message: /kernel: maxproc limit exceeded by uid 0, please see tuning(7) and login.conf(5). Eugene Grosbein
On Fri, 15 Aug 2003, Eugene Grosbein wrote:> Hi! > > It seems /bin/sh in 4.8-STABLE has problem with SIGCHLD processing. > In short, it often fails to process it correctly, zombies float > around, jobs are not marked as finished in jobtab[] that fills memory > and takes much CPU to be processed. > > Run this one-liner using /bin/sh and see hundreds of zombies: > > #!/bin/sh > while :; do : & doneConsidering that with this script you are forkbombing your machine as root, I think this falls into the "doctor it hurts when I shoot my foot" category. -- Doug White | FreeBSD: The Power to Serve dwhite@gumbysoft.com | www.FreeBSD.org
Doug White wrote:> > It seems /bin/sh in 4.8-STABLE has problem with SIGCHLD processing. > > In short, it often fails to process it correctly, zombies float > > around, jobs are not marked as finished in jobtab[] that fills memory > > and takes much CPU to be processed. > > > > Run this one-liner using /bin/sh and see hundreds of zombies: > > > > #!/bin/sh > > while :; do : & done > > Considering that with this script you are forkbombing your machine as > root, I think this falls into the "doctor it hurts when I shoot my foot" > category.Perhaps. Anyway, debug shows that jobtab[] in /bin/sh grows indefinitely in some scenarios and the reason should be SIGCHLD processing problem. Eugene
I think I've found a memory leak in /bin/sh.
There is a case when dowait() and does frees resources of
completed job correctly. Here is a patch:
Index: jobs.c
==================================================================RCS file:
/home/ncvs/src/bin/sh/jobs.c,v
retrieving revision 1.27.2.11
diff -u -r1.27.2.11 jobs.c
--- jobs.c 22 Jul 2003 13:11:26 -0000 1.27.2.11
+++ jobs.c 15 Aug 2003 13:02:23 -0000
@@ -960,10 +960,8 @@
if (jp->state != state) {
TRACE(("Job %d: changing state from %d to %d\n", jp - jobtab +
1, jp->state, state));
jp->state = state;
-#if JOBS
if (done)
- deljob(jp);
-#endif
+ freejob(jp);
}
}
}
Eugene Grosbein
I'm sorry for my terrible English.> There is a case when dowait() and does frees resources of > completed job correctly.Read: There is a case when dowait() does not free resources of completed job correctly. Eugene Grosbein