On 07/27, Toralf Förster wrote: > > I do have a user mode linux image (stable 32 bit Gentoo Linux ) which erratically crashes > while fuzz tested with trinity if the victim files are located on a NFS share. > > The back trace of the core dumps always looks like the attached. > > To bisect it is hard. However after few attempts in the last weeks the following > commit is either the first bad commit or at least the upper limit (less likely). > > > commit 8aac62706adaaf0fab02c4327761561c8bda9448 > Author: Oleg Nesterov <oleg@xxxxxxxxxx> > Date: Fri Jun 14 21:09:49 2013 +0200 > > move exit_task_namespaces() outside of exit_notify() > > #15 nlmclnt_setlockargs (req=0x48e18860, fl=0x48f27c8c) at fs/lockd/clntproc.c:131 Thanks. So nlmclnt_setlockargs()->utsname() crashes and we probably need the patch below. But is it correct? I know _absolutely_ nothing about nfs/sunrpc/etc and I never looked into this code before, most probably I am wrong. But it seems that __nlm_async_call() relies on workqueues. nlmclnt_async_call() does rpc_wait_for_completion_task(), but what if the caller is killed? nlm_rqst can't go away, ->a_count was incremented. But can't the caller exit before call->name is used? In this case the memory it points to can be already freed. Oleg. --- x/kernel/exit.c +++ x/kernel/exit.c @@ -783,8 +783,8 @@ void do_exit(long code) exit_shm(tsk); exit_files(tsk); exit_fs(tsk); - exit_task_namespaces(tsk); exit_task_work(tsk); + exit_task_namespaces(tsk); check_stack_usage(); exit_thread(); -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
