From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 6 Mar 2008 11:55:07 -0800 (PST) From: Christoph Lameter Subject: Re: [BUG] in 2.6.25-rc3 with 64k page size and SLUB_DEBUG_ON In-Reply-To: <200803061447.05797.Jens.Osterkamp@gmx.de> Message-ID: References: <200803061447.05797.Jens.Osterkamp@gmx.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Jens Osterkamp Cc: linux-mm@kvack.org List-ID: On Thu, 6 Mar 2008, Jens Osterkamp wrote: > BUG: scheduling while atomic: kthreadd/2/0x00056ef8 Hmmmm... Fallback? > Call Trace: > [c00000003c187b68] [c00000000000f140] .show_stack+0x70/0x1bc (unreliable) > [c00000003c187c18] [c000000000052d0c] .__schedule_bug+0x64/0x80 > [c00000003c187ca8] [c00000000036fa84] .schedule+0xc4/0x6b0 > [c00000003c187d98] [c0000000003702d0] .schedule_timeout+0x3c/0xe8 > [c00000003c187e68] [c00000000036f82c] .wait_for_common+0x150/0x22c > [c00000003c187f28] [c000000000074868] .kthreadd+0x12c/0x1f0 > [c00000003c187fd8] [c000000000024864] .kernel_thread+0x4c/0x68 But nothing slub wise here... > With slub_debug=- on the kernel command line, the problem is gone. > With 4k page size the problem also does not occur. > Any ideas on why this occurs and how to debug this further ? Could be the result of fallback under debug?? Looks like there is a hole in the fallback logic. But this could be something completely different. If this is slub related then we may not be reenabling interrupt somewhere if debug is on. diff --git a/mm/slub.c b/mm/slub.c index 96d63eb..6d0a103 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1536,8 +1536,14 @@ new_slab: * That is only possible if certain conditions are met that are being * checked when a slab is created. */ - if (!(gfpflags & __GFP_NORETRY) && (s->flags & __PAGE_ALLOC_FALLBACK)) - return kmalloc_large(s->objsize, gfpflags); + if (!(gfpflags & __GFP_NORETRY) && (s->flags & __PAGE_ALLOC_FALLBACK)) { + if (gfpflags & __GFP_WAIT) + local_irq_enable(); + object = kmalloc_large(s->objsize, gfpflags); + if (gfpflags & __GFP_WAIT) + local_irq_disable(); + return object; + } return NULL; debug: -- 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