On Mon, Apr 07, 2014 at 08:16:24PM +0200, Toralf Förster wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > On 04/07/2014 05:07 PM, Peter Zijlstra wrote: > > On Mon, Apr 07, 2014 at 05:03:37PM +0200, Peter Zijlstra wrote: > >> So what I suspect at this point is that because i386 and x86_64 > >> have a difference in current_thread_info() (i386 is stack based), > >> we end up setting the TIF_NEED_RESCHED bit on the wrong stack. > >> > >> Now I have some vague memories of propagating the TIF flags on > >> stack switch, but I cannot remember what arch we did that for. > >> Let me stare at this a little more. > >> > >> Also, IFF this is the case, then the fingered patch above (and > >> your suggested 'fix') aren't the real curlpit/cure but simply > >> make it more/less likely to happen. > >> > >> Now, Steve had a patch somewhere that would make i386 use > >> per-cpu variables for current_thread_info() just like x86_64 > >> already does I think. Let me go find them too. > > > > Ohh, goodie, they're already in Linus' tree. Could you see if > > current git still suffers this problem? > > > v3.14-10353-g2b3a8fd works fine AFAICS > (BTW the fix is stable material, right ?)
If we are reffering to 198d208df4371734ac4728f69cb585c284d20a15 (x86: Keep thread_info on thread stack in x86_32) it doesn't carry a stable tag. So to be clear, you are saying that v3.14 is fine but other release are buggy? Which ones are these? If a backport is needed, 198d208df4371734ac4728f69cb585c284d20a15 looks too large... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/