From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f171.google.com (mail-we0-f171.google.com [74.125.82.171]) by kanga.kvack.org (Postfix) with ESMTP id 1D81E6B0031 for ; Tue, 3 Dec 2013 15:33:13 -0500 (EST) Received: by mail-we0-f171.google.com with SMTP id q58so14260547wes.30 for ; Tue, 03 Dec 2013 12:33:12 -0800 (PST) Received: from smtp2.it.da.ut.ee (smtp2.it.da.ut.ee. [2001:bb8:2002:500:20f:1fff:fe04:1bbb]) by mx.google.com with ESMTP id wd4si16952805wjc.61.2013.12.03.12.33.12 for ; Tue, 03 Dec 2013 12:33:12 -0800 (PST) Date: Tue, 3 Dec 2013 22:33:11 +0200 (EET) From: Meelis Roos Subject: Re: Slab BUG with DEBUG_* options In-Reply-To: <00000142b923d9de-2c71e0b6-7443-46c0-bbde-93a81b50ed37-000000@email.amazonses.com> Message-ID: References: <00000142b923d9de-2c71e0b6-7443-46c0-bbde-93a81b50ed37-000000@email.amazonses.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Pekka Enberg , Matt Mackall , Linux Kernel list , linux-mm@kvack.org, Joonsoo Kim > > I am debugging a reboot problem on Sun Ultra 5 (sparc64) with 512M RAM > > and turned on DEBUG_PAGEALLOC DEBUG_SLAB and DEBUG_SLAB_LEAK (and most > > other debug options) and got the following BUG and hang on startup. This > > happened originally with 3.11-rc2-00058 where my bisection of > > another problem lead, but I retested 3.12 to have the same BUG in the > > same place. > > Hmmm. With CONFIG_DEBUG_PAGEALLOC *and* DEBUG_SLAB you would get a pretty > strange configuration with massive sizes of slabs. > > > kernel BUG at mm/slab.c:2391! > > Ok so this means that we are trying to create a cache with off slab > management during bootstrap which should not happen. [...] > We should not be switching on CFLGS_OFF_SLAB here because the > kmalloc array does not contain the necessary entries yet. > > Does this fix it? We may need a more sophisticated fix from someone who > knows how handle CONFIG_DEBUG_PAGEALLOC. No: Kernel panic - not syncing: Creation of kmalloc slab (null) size=8388608 failed. Reason -7 CPU: 0 PID: 0 Comm: swapper Not tainted 3.11.0-rc2-00058-g20bafb3-dirty #134 Call Trace: [000000000076416c] panic+0xb4/0x22c [0000000000907488] create_boot_cache+0x70/0x84 [00000000009074d0] create_kmalloc_cache+0x34/0x60 [0000000000907540] create_kmalloc_caches+0x44/0x168 [0000000000908dfc] kmem_cache_init+0x1d0/0x1e0 [00000000008fc658] start_kernel+0x18c/0x370 [0000000000761db4] tlb_fixup_done+0x88/0x94 [0000000000000000] (null) Am I just running out of memory perhaps? Will try the other patch soon. -- Meelis Roos (mroos@linux.ee) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org