From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2153EC04A95 for ; Tue, 25 Oct 2022 15:58:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231611AbiJYP6f (ORCPT ); Tue, 25 Oct 2022 11:58:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233171AbiJYP6Z (ORCPT ); Tue, 25 Oct 2022 11:58:25 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7659D17F678; Tue, 25 Oct 2022 08:58:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 305E1B81D7A; Tue, 25 Oct 2022 15:58:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61274C433D6; Tue, 25 Oct 2022 15:58:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666713501; bh=OpTUcEDr5VrpX4nfVD4q9AgajbBKY0H5K0s0qDDSSI0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qMyZ6wpdamWE40WVUaf8ABGbVC9GAU8BgFh4JukUG17uykxX6Adon/d+0En4nILOL JuR6hkdvJf5C4+GHun8FAnfEKgvB6M0sgCKba+4JW6WVvAUu2JjMGA4UXiiHwL2N39 JoZJdJIPAWUk+OJnPP2gQQ5YEmI7gaEM+eK9jlGk= Date: Tue, 25 Oct 2022 17:58:19 +0200 From: Greg Kroah-Hartman To: Hugh Dickins Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Mel Gorman , "Matthew Wilcox (Oracle)" , Yang Shi , Brian Foster , Dan Streetman , Miaohe Lin , Oleksandr Natalenko , Seth Jennings , Vitaly Wool , Andrew Morton , Tvrtko Ursulin Subject: Re: [PATCH 6.0 19/20] mm/huge_memory: do not clobber swp_entry_t during THP split Message-ID: References: <20221024112934.415391158@linuxfoundation.org> <20221024112935.173960536@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 25, 2022 at 08:11:44AM -0700, Hugh Dickins wrote: > On Mon, 24 Oct 2022, Greg Kroah-Hartman wrote: > > From: Mel Gorman > > > > commit 71e2d666ef85d51834d658830f823560c402b8b6 upstream. > > > > The following has been observed when running stressng mmap since commit > > b653db77350c ("mm: Clear page->private when splitting or migrating a page") > > > > watchdog: BUG: soft lockup - CPU#75 stuck for 26s! [stress-ng:9546] > > CPU: 75 PID: 9546 Comm: stress-ng Tainted: G E 6.0.0-revert-b653db77-fix+ #29 0357d79b60fb09775f678e4f3f64ef0579ad1374 > > Hardware name: SGI.COM C2112-4GP3/X10DRT-P-Series, BIOS 2.0a 05/09/2016 > > RIP: 0010:xas_descend+0x28/0x80 > > Code: cc cc 0f b6 0e 48 8b 57 08 48 d3 ea 83 e2 3f 89 d0 48 83 c0 04 48 8b 44 c6 08 48 89 77 18 48 89 c1 83 e1 03 48 83 f9 02 75 08 <48> 3d fd 00 00 00 76 08 88 57 12 c3 cc cc cc cc 48 c1 e8 02 89 c2 > > RSP: 0018:ffffbbf02a2236a8 EFLAGS: 00000246 > > RAX: ffff9cab7d6a0002 RBX: ffffe04b0af88040 RCX: 0000000000000002 > > RDX: 0000000000000030 RSI: ffff9cab60509b60 RDI: ffffbbf02a2236c0 > > RBP: 0000000000000000 R08: ffff9cab60509b60 R09: ffffbbf02a2236c0 > > R10: 0000000000000001 R11: ffffbbf02a223698 R12: 0000000000000000 > > R13: ffff9cab4e28da80 R14: 0000000000039c01 R15: ffff9cab4e28da88 > > FS: 00007fab89b85e40(0000) GS:ffff9cea3fcc0000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007fab84e00000 CR3: 00000040b73a4003 CR4: 00000000003706e0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > > > xas_load+0x3a/0x50 > > __filemap_get_folio+0x80/0x370 > > ? put_swap_page+0x163/0x360 > > pagecache_get_page+0x13/0x90 > > __try_to_reclaim_swap+0x50/0x190 > > scan_swap_map_slots+0x31e/0x670 > > get_swap_pages+0x226/0x3c0 > > folio_alloc_swap+0x1cc/0x240 > > add_to_swap+0x14/0x70 > > shrink_page_list+0x968/0xbc0 > > reclaim_page_list+0x70/0xf0 > > reclaim_pages+0xdd/0x120 > > madvise_cold_or_pageout_pte_range+0x814/0xf30 > > walk_pgd_range+0x637/0xa30 > > __walk_page_range+0x142/0x170 > > walk_page_range+0x146/0x170 > > madvise_pageout+0xb7/0x280 > > ? asm_common_interrupt+0x22/0x40 > > madvise_vma_behavior+0x3b7/0xac0 > > ? find_vma+0x4a/0x70 > > ? find_vma+0x64/0x70 > > ? madvise_vma_anon_name+0x40/0x40 > > madvise_walk_vmas+0xa6/0x130 > > do_madvise+0x2f4/0x360 > > __x64_sys_madvise+0x26/0x30 > > do_syscall_64+0x5b/0x80 > > ? do_syscall_64+0x67/0x80 > > ? syscall_exit_to_user_mode+0x17/0x40 > > ? do_syscall_64+0x67/0x80 > > ? syscall_exit_to_user_mode+0x17/0x40 > > ? do_syscall_64+0x67/0x80 > > ? do_syscall_64+0x67/0x80 > > ? common_interrupt+0x8b/0xa0 > > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > > > The problem can be reproduced with the mmtests config > > config-workload-stressng-mmap. It does not always happen and when it > > triggers is variable but it has happened on multiple machines. > > > > The intent of commit b653db77350c patch was to avoid the case where > > PG_private is clear but folio->private is not-NULL. However, THP tail > > pages uses page->private for "swp_entry_t if folio_test_swapcache()" as > > stated in the documentation for struct folio. This patch only clobbers > > page->private for tail pages if the head page was not in swapcache and > > warns once if page->private had an unexpected value. > > > > Link: https://lkml.kernel.org/r/20221019134156.zjyyn5aownakvztf@techsingularity.net > > Fixes: b653db77350c ("mm: Clear page->private when splitting or migrating a page") > > Signed-off-by: Mel Gorman > > Cc: Matthew Wilcox (Oracle) > > Cc: Mel Gorman > > Cc: Yang Shi > > Cc: Brian Foster > > Cc: Dan Streetman > > Cc: Miaohe Lin > > Cc: Oleksandr Natalenko > > Cc: Seth Jennings > > Cc: Vitaly Wool > > Cc: > > Signed-off-by: Andrew Morton > > Signed-off-by: Greg Kroah-Hartman > > Greg, this patch from Mel is important, > but introduces a warning which is giving Tvrtko trouble - see linux-mm > https://lore.kernel.org/linux-mm/1596edbb-02ad-6bdf-51b8-15c2d2e08b76@linux.intel.com/ > > We already have the fix for the warning, it's making its way through the > system, and is marked for stable, but it has not reached Linus's tree yet. > > Please drop this 19/20 from 6.0.4, then I'll reply to this to let you know > when the fix does reach Linus's tree - hopefully the two can go together > in the next 6.0-stable. > > I apologize for not writing yesterday: gmail had gathered together > different threads with the same subject, I thought you and stable > were Cc'ed on the linux-mm mail and you would immediately drop it > yourself, but in fact you were not on that thread at all. No worries, now dropped, thanks. greg k-h