You added a dead-lock:
* shm_lock() is a spinlock.
* shm_swap() is called from try_to_free_pages(), and that function could
be called with the big kernel lock acquired; shm_swap() calls
shm_lockall().
Alan Cox wrote:
> + shp = shm_lock(shmid);
^^^^^^^^^^^^^^^ spinlock acquired.
> + if(shp==NULL)
> + return -EINVAL;
> + err=-EIDRM;
> + if(shm_checkid(shp,shmid))
> + goto out_unlock;
> + if(shp->nattch==0)
> + shm_remove_name(shmid);
[...]
>
> +static void shm_remove_name(int id)
> +{
> + char *name = shm_getname(id);
> + if (!IS_ERR(name))
> + {
> + struct dentry *saved;
> + lock_kernel();
^^^^^^^^^^^^^^^^^^^^^^^^^^^ and lock_kernel().
> + saved=shm_push_chroot();
> + do_unlink (name);
I documented the spinlock ordering in shm.c, ~ line 190.
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This archive was generated by hypermail 2b29 : Wed Mar 15 2000 - 21:00:23 EST