Messages in this thread Patch in this message | | | Date | Wed, 12 Dec 2007 15:47:58 -0500 | From | Jeff Dike <> | Subject | [PATCH 2/6] 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> --- 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);
| |