This is a fix for the problem where get_pid will hang the machine if you
request a new pid when all available pids are in use. This also adds
the appropriate checking for p->tgid in get_pid that was somehow
overlooked before. This patch has been in 2.4 since 2.4.19-pre9.
Please apply.
Paul Larson
Linux Test Project
http://ltp.sourceforge.net
diff -Nru a/kernel/fork.c b/kernel/fork.c
--- a/kernel/fork.c Mon Jul 29 15:15:36 2002
+++ b/kernel/fork.c Mon Jul 29 15:15:36 2002
@@ -26,6 +26,7 @@
#include <linux/mman.h>
#include <linux/fs.h>
#include <linux/security.h>
+#include <linux/compiler.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -136,12 +137,13 @@
{
static int next_safe = PID_MAX;
struct task_struct *p;
- int pid;
+ int pid, beginpid;
if (flags & CLONE_IDLETASK)
return 0;
spin_lock(&lastpid_lock);
+ beginpid = last_pid;
if((++last_pid) & 0xffff8000) {
last_pid = 300; /* Skip daemons etc. */
goto inside;
@@ -161,12 +163,16 @@
last_pid = 300;
next_safe = PID_MAX;
}
+ if(unlikely(last_pid == beginpid))
+ goto nomorepids;
goto repeat;
}
if(p->pid > last_pid && next_safe > p->pid)
next_safe = p->pid;
if(p->pgrp > last_pid && next_safe > p->pgrp)
next_safe = p->pgrp;
+ if(p->tgid > last_pid && next_safe > p->tgid)
+ next_safe = p->tgid;
if(p->session > last_pid && next_safe > p->session)
next_safe = p->session;
}
@@ -176,6 +182,11 @@
spin_unlock(&lastpid_lock);
return pid;
+
+nomorepids:
+ read_unlock(&tasklist_lock);
+ spin_unlock(&lastpid_lock);
+ return 0;
}
static inline int dup_mmap(struct mm_struct * mm)
@@ -677,6 +688,8 @@
copy_flags(clone_flags, p);
p->pid = get_pid(clone_flags);
+ if (p->pid == 0 && !(clone_flags & CLONE_IDLETASK))
+ goto bad_fork_cleanup;
p->proc_dentry = NULL;
INIT_LIST_HEAD(&p->run_list);
-
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This archive was generated by hypermail 2b29 : Tue Jul 30 2002 - 14:00:33 EST