From: kanoj@google.engr.sgi.com (Kanoj Sarcar)
To: Linux-MM@kvack.org, linux-kernel@vger.rutgers.edu
Subject: boundary condition bug fix for vmalloc()
Date: Wed, 21 Apr 1999 17:12:37 -0700 (PDT) [thread overview]
Message-ID: <199904220012.RAA57724@google.engr.sgi.com> (raw)
Hi,
Under heavy load conditions, get_vm_area() might end up allocating an
address range beyond VMALLOC_END. The problem is after the for loop
in get_vm_area() terminates, no consistency check (addr > VMALLOC_END
- size) is performed on the "addr".
I believe the following patch will fix the problem:
--- vmalloc.old Wed Apr 21 16:52:05 1999
+++ mm/vmalloc.c Wed Apr 21 16:53:08 1999
@@ -161,11 +161,11 @@
for (p = &vmlist; (tmp = *p) ; p = &tmp->next) {
if (size + addr < (unsigned long) tmp->addr)
break;
+ addr = tmp->size + (unsigned long) tmp->addr;
if (addr > VMALLOC_END-size) {
kfree(area);
return NULL;
}
- addr = tmp->size + (unsigned long) tmp->addr;
}
area->addr = (void *)addr;
area->size = size + PAGE_SIZE;
Please let me know if this patch is pulled into the source tree,
so I can update my tree.
Thanks.
Kanoj
kanoj@engr.sgi.com
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next reply other threads:[~1999-04-22 1:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-04-22 0:12 Kanoj Sarcar [this message]
1999-04-22 15:30 ` Patch: Re: boundary condition bug fix for vmalloc() Stephen C. Tweedie
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