Hi Sebastian, On Mon, Apr 15, 2019 at 04:38:57PM +0200, Sebastian Andrzej Siewior wrote: > On 2019-04-13 17:00:59 [+0000], Kirill Smelkov wrote: > > Hello everyone, > Hi, > > > On Sat, Apr 13, 2019 at 06:50:57PM +0200, Julia Lawall wrote: > > > Hello, > > > > > > Kirill will explain about this issue. > > > > pci/switchtec switching to stream_open is already queued to merge > > window and it was acked by Logan Gunthorpe: > > > > > > https://lore.kernel.org/lkml/CAHk-=wgqgN5j1ZWnyVLqqoyU=ccwtyoko3mdyu8l_5e21kv...@mail.gmail.com/ > > https://lab.nexedi.com/kirr/linux/commit/edaeb4101860 > > > > ( there are too many Cc's in that patch and email with it and reply-all to > > it did not get into mailing list probably due to being considered as spam > > ) > > > > stream_open.cocci was issuing only warning for pci/switchtec, but after > > 8a29a3bae2a2 ("pci/switchtec: Don't use completion's wait queue") they > > started to use wait_even_* inside read method and, since > > stream_open.cocci considers wait_event_* as blocking the warning became > > error. Previously it was completions there, but I added support for wait > > events only for simplicity. > > why is wait_event_interruptible() treated differently compared to > wait_for_completion_interruptible()?
No particular reason. I just taught stream_open.cocci to consider only "wait_event_*" as blocking: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/coccinelle/api/stream_open.cocci?h=v5.1-rc5#n35 based on original /proc/xen/xenbus deadlock: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/xen/xenbus/xenbus_dev_frontend.c?h=v5.1-rc5#n135 https://git.kernel.org/linus/581d21a2d02a We can extend "a function that blocks" rule to cover other kernel primitives. For the reference: the deadlock scenario is described in https://git.kernel.org/linus/10dce8af3422 Kirill
