From: azu <azu@sysgo.de>
To: user-mode-linux-devel@lists.sourceforge.net
Subject: [uml-devel] Patch for arch/um/kernel/trap_kern.c to fix bad panic
Date: Mon, 28 Jun 2004 13:39:25 +0200 [thread overview]
Message-ID: <40E0036D.2070108@sysgo.de> (raw)
Hi,
I triggered the following panic from userspace in skas mode
by mapping pages above 0xa0000000 ...
The check is useless in skas-mode (kernel faults get filtered
in segv() before handle_page_fault() is called),
so I added an ifdef for tt mode.
-Alex
--- orig/arch/um/kernel/trap_kern.c 2004-06-28 13:08:41.000000000 +0200
+++ u4/arch/um/kernel/trap_kern.c 2004-06-28 13:08:52.000000000 +0200
@@ -52,8 +52,10 @@
if(is_write && !(vma->vm_flags & VM_WRITE))
goto out;
page = address & PAGE_MASK;
+#ifdef CONFIG_MODE_TT
if(page == (unsigned long) current + PAGE_SIZE)
panic("Kernel stack overflow");
+#endif
pgd = pgd_offset(mm, page);
pmd = pmd_offset(pgd, page);
do {
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next reply other threads:[~2004-06-28 11:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-28 11:39 azu [this message]
2004-06-29 18:34 ` [uml-devel] Patch for arch/um/kernel/trap_kern.c to fix bad panic BlaisorBlade
2004-06-30 10:04 ` [uml-devel] bad panic "Kernel stack overflow" - demo exploit azu
2004-07-01 12:01 ` BlaisorBlade
2004-07-01 13:34 ` BlaisorBlade
2004-07-01 17:57 ` Alex Züpke
2004-07-01 19:33 ` BlaisorBlade
2004-07-03 18:25 ` BlaisorBlade
2004-08-17 15:40 ` BlaisorBlade
2004-08-20 15:09 ` Jeff Dike
2004-09-05 16:41 ` BlaisorBlade
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