From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 8D14C6B004D for ; Wed, 8 Jul 2009 06:59:23 -0400 (EDT) Date: Wed, 8 Jul 2009 13:07:31 +0200 (CEST) From: Guennadi Liakhovetski Subject: [BUG 2.6.30] Bad page map in process Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: linux-kernel@vger.kernel.org Cc: kernel@avr32linux.org, linux-mm@kvack.org List-ID: Hi with a 2.6.30 kernel with only platform-specific modifications and this avr32 patch: http://git.kernel.org/?p=linux/kernel/git/sfr/linux-next.git;a=commitdiff;h=bb6e647051a59dca5a72b3deef1e061d7c1c34da we're seeing kernel BUGs following an application segfault. Here's an example: [60254.432000] application[465]: segfault at 4377f876 pc 2aaabbde sp 7faa77f0 ecr 24 [60255.396000] BUG: Bad page map in process application pte:13f26ed4 pmd:92fdd000 [60255.404000] page:902c44c0 flags:0000002c count:1 mapcount:-1 mapping:9345765c index:5 [60255.412000] addr:2ae4f000 vm_flags:08000075 anon_vma:(null) mapping:93454dd4 index:0 [60255.420000] vma->vm_ops->fault: filemap_fault+0x0/0x26c [60255.424000] vma->vm_file->f_op->mmap: generic_file_readonly_mmap+0x0/0x18 [60255.432000] Call trace: [60255.432000] [<90027b7c>] dump_stack+0x18/0x20 [60255.432000] [<9005f2e8>] print_bad_pte+0x120/0x13c [60255.432000] [<90060964>] unmap_vmas+0x230/0x3e4 [60255.432000] [<90061ed2>] exit_mmap+0x5e/0xd0 [60255.432000] [<9002d380>] mmput+0x24/0x7c [60255.432000] [<9002fd70>] exit_mm+0xb4/0xb8 [60255.432000] [<90030ede>] do_exit+0xde/0x3d8 [60255.432000] [<90031222>] do_group_exit+0x4a/0x64 [60255.432000] [<9003688e>] get_signal_to_deliver+0x22a/0x24c [60255.432000] [<900272ce>] do_signal+0x52/0x3f0 [60255.432000] [<90027698>] do_notify_resume+0x2c/0xfc [60255.432000] [<900233d2>] fault_exit_work+0x24/0x36 [60255.432000] [60255.432000] Disabling lock debugging due to kernel taint [60255.432000] BUG: Bad page state in process application pfn:13f26 [60255.440000] page:902c44c0 flags:0000000c count:0 mapcount:-1 mapping:9345765c index:5 [60255.448000] Call trace: [60255.448000] [<90027b7c>] dump_stack+0x18/0x20 [60255.448000] [<90054c76>] bad_page+0xa6/0xd0 [60255.448000] [<900557e6>] free_hot_cold_page+0xa2/0x160 [60255.448000] [<900558dc>] free_hot_page+0x8/0xc [60255.448000] [<90057bae>] put_page+0xca/0xe8 [60255.448000] [<900662a4>] free_page_and_swap_cache+0x38/0x3c [60255.448000] [<90060972>] unmap_vmas+0x23e/0x3e4 [60255.448000] [<90061ed2>] exit_mmap+0x5e/0xd0 [60255.448000] [<9002d380>] mmput+0x24/0x7c [60255.448000] [<9002fd70>] exit_mm+0xb4/0xb8 [60255.448000] [<90030ede>] do_exit+0xde/0x3d8 [60255.448000] [<90031222>] do_group_exit+0x4a/0x64 [60255.448000] [<9003688e>] get_signal_to_deliver+0x22a/0x24c [60255.448000] [<900272ce>] do_signal+0x52/0x3f0 [60255.448000] [<90027698>] do_notify_resume+0x2c/0xfc [60255.448000] [<900233d2>] fault_exit_work+0x24/0x36 [60255.448000] Questions: can this BUG be caused by the segfault (it better not)? If not, what can be the reason? The problem occurs sporadically, I've only had one such case since yesterday. Yet one more application segfault last night didn't produce a BUG. This is with a kernel configured with SLAB. With SLUB we also observed similar BUGs on application exit but without signal handling path in the backtrace. But, I think, I've had other problems with SLUB before, so, we switched back to SLAB for now... Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- 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