lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 20 Oct 2009 08:15:57 +0200 From: Ingo Molnar <mingo@...e.hu> To: Jiri Kosina <jkosina@...e.cz> Cc: Jeff Mahoney <jeffm@...e.com>, Peter Zijlstra <peterz@...radead.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Tony Luck <tony.luck@...el.com>, Fenghua Yu <fenghua.yu@...el.com>, linux-ia64@...r.kernel.org Subject: Re: Commit 34d76c41 causes linker errors on ia64 with NR_CPUS=4096 * Jiri Kosina <jkosina@...e.cz> wrote: > On Tue, 20 Oct 2009, Jiri Kosina wrote: > > > > Commit 34d76c41 introduced the update_shares_data percpu, but it ends up > > > causing problems on large ia64 machines. Specifically, ia64 is limited > > > to 64k in percpu vars and with NR_CPUS=4096, that ends up being 32k by > > > itself. It ends up causing link errors since that is how ia64 enforces > > > the 64k limit. > > > > > > I can take a deeper look at finding a workable solution but thought I'd > > > mention it in case you had ideas already. > > > > I am adding some IA64 CCs, as the failure is solely caused by the ia64 > > percpu implementation/pagefault handler optimization which requires the > > .percpu section area not be larger than 64k, which blows up with 34d76c41 > > and NR_CPUS high enoufh (due to introduction of percpu array being > > size-dependent on NR_CPUS). > > How about this one? (untested) > > > > From: Jiri Kosina <jkosina@...e.cz> > Subject: sched: move rq_weight data array out of .percpu > > Commit 34d76c41 introduced percpu array update_shares_data, size of which > being proportional to NR_CPUS. Unfortunately this blows up ia64 for large > NR_CPUS configuration, as ia64 allows only 64k for .percpu section. > > Fix this by allocating this array dynamically and keep only pointer to it > percpu. > > Signed-off-by: Jiri Kosina <jkosina@...e.cz> > --- > kernel/sched.c | 15 +++++++-------- > 1 files changed, 7 insertions(+), 8 deletions(-) Seems like an IA64 bug to me. It's _very_ easy to get more than 64K of percpu data - i'm wondering why IA64 only triggered it now? Sure lockdep/lockstat must have triggered it before. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists