On 2017-10-10 09:21, Joerg Roedel wrote: > On Mon, Oct 09, 2017 at 06:58:13PM +0200, Jan Kiszka wrote: >>> extern int dmar_table_init(void); >>> extern int dmar_dev_scope_init(void); >>> +extern void dmar_register_bus_notifier(void); >>> extern int dmar_parse_dev_scope(void *start, void *end, int *cnt, >>> struct dmar_dev_scope **devices, u16 segment); >>> extern void *dmar_alloc_dev_scope(void *start, void *end, int *cnt); >>> >> >> Silences the warning, but locking in the init paths still smells fishy >> to me. > > Yes, its certainly not optimal, but the code that runs in there also > runs at iommu hotplug time, so we can't just remove the locking there > entirely.
It may not just be "sub-optimal" but rather borken: "One example: dmar_table_init is not consistently protected by dmar_global_lock." Jan > > On the other side the warning you reported is a false-positive, it can > never dead-lock because the reverse lock-order happens only at > initialization time, but I don't know how to silence it otherwise. > > > Regards, > > Joerg > -- Siemens AG, Corporate Technology, CT RDA ITP SES-DE Corporate Competence Center Embedded Linux
