Messages in this thread | | | Subject | Re: [regression] x86/signal/64: Fix SS handling for signals delivered to 64-bit programs breaks dosemu | From | Raymond Jennings <> | Date | Thu, 13 Aug 2015 16:35:30 -0700 |
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On 08/13/15 16:18, Linus Torvalds wrote: > On Thu, Aug 13, 2015 at 4:05 PM, Linus Torvalds > <torvalds@linux-foundation.org> wrote: >> The _only_ thing that matters is that something broke. > To clarify: things like test programs etc don't matter. Real > applications, used by real users. That's what regressions cover. If > you have a workflow that isn't just some random kernel test thing, and > you depend on it, and we break it, the kernel is supposed to fix it. > > There are some (very few) exceptions. > > If it's a security issue, we may not be able to "fix" it, because > other concerns can obviously take precedence. > > Also, sometimes the reports come in way too late - if you were running > some stable distro kernel for several years, and updated, and notice a > change that happened four years ago and modern applications now rely > on the _new_ behavior, we may not be able to fix the regression any > more. > > But no, "it was an unintentional kernel bug and clearly just stupid > crap code, and we fixed it and now the kernel is much better and > cleaner" is not a valid reason for regressions. We'll go back to the > stupid and crap code if necessary, however much that may annoy us. > > For an example of the kind of things we may have to do, see commits > > 64f371bc3107 autofs: make the autofsv5 packet file descriptor use > a packetized pipe > 9883035ae7ed pipes: add a "packetized pipe" mode for writing > > and just wonder at the insanity. That's the kinds of things that > happen when one application had actively worked around a bug in > compatibility handling, and then trying to "fix" that bug just caused > another application to break instead. > > Linus Is there a way to temporally confine the bad crap code just to the applications that depend on it, or does a userspace app latching onto bad behavior effectively lock down the abi for the future?
I know that some features in the kernel get deprecated over a process (devfs for example) once userspace is given an alternative...would there be a process like that to deal with userspace code that is pinning a piece of crap in the kernel?
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