Messages in this thread |  | | Date | Mon, 7 May 2001 22:34:41 -0300 (BRT) | From | Marcelo Tosatti <> | Subject | Re: page_launder() bug |
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On Mon, 7 May 2001, David S. Miller wrote:
> > Linus Torvalds writes: > > YOUR HEURISTIC IS WRONG! > > Please start the conversation this way next time. > > > I call that a bug. You don't. Fine. > > You made it sound like a data corrupter, a kernel crasher, and that > any bug against a kernel with that patch indicates my patch caused it. > There is an important distinction between "this is doing something > silly" and "this will scramble your disk and crash the kernel". > > The latter is the conclusion several people came to. > > And I wanted a clarification on this, nothing more. > > I wanted this clarification from you _BECAUSE_ the original posting in > this thread saw data corruption which went away after reverting my > patch. But there is no possible connection between my patch and the > crashes he saw.
Ugh, there is.
I just thought about this case:
We find a dead swap cache page, so dead_swap_page goes to 1.
We call swap_writepage(), but in the meantime the swapin readahead code got a reference on the swap map for the page.
We write the page out because "(swap_count(page) > 1)", and we may not have __GFP_IO set in the gfp_mask. Boom.
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