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authorJeff Dike <jdike@addtoit.com>2008-02-04 22:31:10 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 09:44:30 -0800
commit00a905e6145ba200308a6a13e00248b85c600bd0 (patch)
tree678bd7baeb62c7d9584967d97a83f5bb3cb938e8
parent1aa351a308d2c3ddb92b6cc45083fc54271d0010 (diff)
uml: don't kill pid 0
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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/um/kernel/skas/mmu.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index e8dc8540d44..78b3e9f69d5 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -164,8 +164,20 @@ void destroy_context(struct mm_struct *mm)
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);