diff options
| author | Jeff Dike <jdike@addtoit.com> | 2008-02-04 22:31:10 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-05 09:44:30 -0800 |
| commit | 00a905e6145ba200308a6a13e00248b85c600bd0 (patch) | |
| tree | 678bd7baeb62c7d9584967d97a83f5bb3cb938e8 /arch/um/kernel | |
| parent | 1aa351a308d2c3ddb92b6cc45083fc54271d0010 (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>
Diffstat (limited to 'arch/um/kernel')
| -rw-r--r-- | arch/um/kernel/skas/mmu.c | 14 |
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); |