Messages in this thread | | | Date | Sat, 30 Jun 2001 12:30:48 -0300 (BRT) | From | Marcelo Tosatti <> | Subject | Re: Bounce buffer deadlock |
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On Fri, 29 Jun 2001, Steve Lord wrote:
> > Has anyone else seen a hang like this: > > bdflush() > flush_dirty_buffers() > ll_rw_block() > submit_bh(buffer X) > generic_make_request() > __make_request() > create_bounce() > alloc_bounce_page() > alloc_page() > try_to_free_pages() > do_try_to_free_pages() > page_launder() > try_to_free_buffers( , 2) -- i.e. wait for buffers > sync_page_buffers() > __wait_on_buffer(buffer X) > > Where the buffer head X going in the top of the stack is the same as the one > we wait on at the bottom. > > There still seems to be nothing to prevent the try to free buffers from > blocking on a buffer like this. Setting a flag on the buffer around the > create_bounce call, and skipping it in the try_to_free_buffers path would > be one approach to avoiding this.
Yes there is a bug: Linus is going to put a new fix soon.
> I hit this in 2.4.6-pre6, and I don't see anything in the ac series to protect > against it.
Thats because the -ac series does not contain the __GFP_BUFFER/__GFP_IO moditications which are in the -ac series.
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