From: Jeff Dike <jdike@addtoit.com>
To: Andrew Morton <akpm@osdl.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
uml-devel <user-mode-linux-devel@lists.sourceforge.net>
Subject: [uml-devel] [PATCH 2/6] UML - don't kill pid 0
Date: Wed, 12 Dec 2007 15:47:58 -0500 [thread overview]
Message-ID: <20071212204758.GA9124@c2.user-mode-linux.org> (raw)
A bit of defensive programming - during development, it ocassionally
happens that a call to init_new_context is missed, resulting in
context holding a host pid of zero. When that address space is torn
down, destroy_context does a kill(0), which instantly kills the whole
UML without any errors whatsoever.
This patch add a check for pids less than 2, to also catch 1 and
negative pids.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
---
arch/um/kernel/skas/mmu.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
Index: linux-2.6-git/arch/um/kernel/skas/mmu.c
===================================================================
--- linux-2.6-git.orig/arch/um/kernel/skas/mmu.c 2007-12-12 15:06:14.000000000 -0500
+++ linux-2.6-git/arch/um/kernel/skas/mmu.c 2007-12-12 15:12:11.000000000 -0500
@@ -164,8 +164,20 @@ void destroy_context(struct mm_struct *m
if (proc_mm)
os_close_file(mmu->id.u.mm_fd);
- else
+ else {
+ /*
+ * If init_new_context wasn't called, this will be
+ * zero, resulting in a kill(0), which will result in the
+ * whole UML suddenly dying. Also, cover negative and
+ * 1 cases, since they shouldn't happen either.
+ */
+ if (mmu->id.u.pid < 2) {
+ printk(KERN_ERR "corrupt mm_context - pid = %d\n",
+ mmu->id.u.pid);
+ return;
+ }
os_kill_ptraced_process(mmu->id.u.pid, 1);
+ }
if (skas_needs_stub)
free_page(mmu->id.stack);
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WARNING: multiple messages have this Message-ID (diff)
From: Jeff Dike <jdike@addtoit.com>
To: Andrew Morton <akpm@osdl.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
uml-devel <user-mode-linux-devel@lists.sourceforge.net>
Subject: [PATCH 2/6] UML - don't kill pid 0
Date: Wed, 12 Dec 2007 15:47:58 -0500 [thread overview]
Message-ID: <20071212204758.GA9124@c2.user-mode-linux.org> (raw)
A bit of defensive programming - during development, it ocassionally
happens that a call to init_new_context is missed, resulting in
context holding a host pid of zero. When that address space is torn
down, destroy_context does a kill(0), which instantly kills the whole
UML without any errors whatsoever.
This patch add a check for pids less than 2, to also catch 1 and
negative pids.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
---
arch/um/kernel/skas/mmu.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
Index: linux-2.6-git/arch/um/kernel/skas/mmu.c
===================================================================
--- linux-2.6-git.orig/arch/um/kernel/skas/mmu.c 2007-12-12 15:06:14.000000000 -0500
+++ linux-2.6-git/arch/um/kernel/skas/mmu.c 2007-12-12 15:12:11.000000000 -0500
@@ -164,8 +164,20 @@ void destroy_context(struct mm_struct *m
if (proc_mm)
os_close_file(mmu->id.u.mm_fd);
- else
+ else {
+ /*
+ * If init_new_context wasn't called, this will be
+ * zero, resulting in a kill(0), which will result in the
+ * whole UML suddenly dying. Also, cover negative and
+ * 1 cases, since they shouldn't happen either.
+ */
+ if (mmu->id.u.pid < 2) {
+ printk(KERN_ERR "corrupt mm_context - pid = %d\n",
+ mmu->id.u.pid);
+ return;
+ }
os_kill_ptraced_process(mmu->id.u.pid, 1);
+ }
if (skas_needs_stub)
free_page(mmu->id.stack);
next reply other threads:[~2007-12-12 20:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-12 20:47 Jeff Dike [this message]
2007-12-12 20:47 ` [PATCH 2/6] UML - don't kill pid 0 Jeff Dike
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