From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5928539937C; Wed, 3 Jun 2026 22:47:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780526860; cv=none; b=XvmwS5qGj8W5Cr2tCxAwkNvmqVUMXAeCiSRGEF/pxIEXkE6c5n/c4q1GKtmj3GVVdAEqHs1Fhs5d/UDEEUxKBn50JAukXQddVS6GDNcNQAkuVh3AcFjcie5WWYxkwFEzJvKjQC2/EH8CRT4wbBaJGWaGkyT/W3rIEtpi2Ji0kRM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780526860; c=relaxed/simple; bh=ZV+Xpf9PyZcS+HBhg5FGmb1f2Ta9ZZK3p9sL9wGC+yE=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=NaWdbZklZ5PoTdjfqRoJBcwuQoAvpHCjakP6rT4KBTx7ZqFO6FCHjEGNTAQKwETtTewtS/4+CXRf+A8tzFNGCdjB76KJ7WOo3rXXy+EW8JmzAzuvIdhSpvQw3zn7ltL1gcshzaclqNmErFWDOebZYz8ZDeiUph69Kcx1RMqhfn0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=bbQqIZXO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="bbQqIZXO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 691F51F00893; Wed, 3 Jun 2026 22:47:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1780526858; bh=R7Sz/+Fr0suuQeg6EVNsiUNZZL7j8WmTr/VEGuzHW30=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=bbQqIZXOyyk7fzneEICQY56/lMcWDjClRrPFceC+/rWMhGEB8XAK3dziozHfdH17j E1rwgyU6ZGwyFv/ZX4LcK+Irri7OE4WdDAFgP11VfB3U0LzlFzuLbUmz9064VNmFbZ abaVMIlu4z9qNTtnU8HxF3YjN2Pdly1LauygKJdc= Date: Wed, 3 Jun 2026 15:47:37 -0700 From: Andrew Morton To: syzbot Cc: apopple@nvidia.com, byungchul@sk.com, david@kernel.org, gourry@gourry.net, joshua.hahnjy@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-next@vger.kernel.org, matthew.brost@intel.com, rakie.kim@sk.com, sfr@canb.auug.org.au, syzkaller-bugs@googlegroups.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, "Michael S . Tsirkin" Subject: Re: [syzbot] [mm?] linux-next test error: kernel BUG in post_alloc_hook Message-Id: <20260603154737.48dfcc19a51da03241e1af48@linux-foundation.org> In-Reply-To: <6a20a309.85ccb786.283107.0005.GAE@google.com> References: <6a20a309.85ccb786.283107.0005.GAE@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit (cc Mike Tsirkin) On Wed, 03 Jun 2026 14:56:25 -0700 syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: a225caacc365 Add linux-next specific files for 20260603 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=13b0de66580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=717edf2a5f9fc390 > dashboard link: https://syzkaller.appspot.com/bug?extid=8ffca916f3fa5455f9b4 > compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/f799d07ea17d/disk-a225caac.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/72d0f0ff94e6/vmlinux-a225caac.xz > kernel image: https://storage.googleapis.com/syzbot-assets/99d4279e6fec/bzImage-a225caac.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+8ffca916f3fa5455f9b4@syzkaller.appspotmail.com > > ... > > ********************************************************** > ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** > ** ** > ** This system shows unhashed kernel memory addresses ** > ** via the console, logs, and other interfaces. This ** > ** might reduce the security of your system. ** > ** ** > ** If you see this message and you are not debugging ** > ** the kernel, report this immediately to your system ** > ** administrator! ** > ** ** > ** Use hash_pointers=always to force this mode off ** > ** ** > ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** > ********************************************************** Geeze, who added that. > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13fe38 > head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > flags: 0x100000000000040(head|node=0|zone=2) > raw: 0100000000000040 dead000000000100 dead000000000122 0000000000000000 > raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 > head: 0100000000000040 dead000000000100 dead000000000122 0000000000000000 > head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 > head: 0100000000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff > head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004 > page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page)) > ------------[ cut here ]------------ > kernel BUG at ./include/linux/page-flags.h:682! > Oops: invalid opcode: 0000 [#1] SMP KASAN PTI > CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted syzkaller #0 PREEMPT_{RT,(undef)} > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 > RIP: 0010:__ClearPagePrezeroed include/linux/page-flags.h:682 [inline] > RIP: 0010:post_alloc_hook+0x287/0x310 mm/page_alloc.c:1863 That's the __ClearPagePrezeroed(page) added by 504f40f6bda6 ("mm: page_reporting: skip redundant zeroing of host-zeroed reported pages"). Was it intended that this series (https://lore.kernel.org/cover.1779315441.git.mst@redhat.com) be included in -next? It's huge, it's late, review is minor. > Code: ff ff 89 da be 01 00 00 00 48 c7 c7 40 50 4f 8e e8 ce 4b d4 02 e9 c5 fe ff ff 4c 89 ef 48 c7 c6 40 ef 7a 8b e8 2a c6 05 ff 90 <0f> 0b 31 ed f7 44 24 04 00 01 00 00 0f 84 8e fd ff ff e9 86 fd ff > RSP: 0000:ffffffff8e0078e0 EFLAGS: 00010046 > RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff8e0fef40 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 > R10: dffffc0000000000 R11: ffffed10170c4903 R12: dffffc0000000000 > R13: ffffea0004ff8e00 R14: 1ffffd40009ff1c0 R15: 0000000000000000 > FS: 0000000000000000(0000) GS:ffff888125a79000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffff88823ffff000 CR3: 000000000e1b8000 CR4: 00000000000100b0 > Call Trace: > > prep_new_page mm/page_alloc.c:1925 [inline] > get_page_from_freelist+0x3081/0x3320 mm/page_alloc.c:4015 > __alloc_frozen_pages_noprof+0x194/0x380 mm/page_alloc.c:5376 > __alloc_pages_mpol+0xe0/0x390 mm/mempolicy.c:2495 > alloc_slab_page mm/slub.c:3287 [inline] > allocate_slab+0x83/0x5e0 mm/slub.c:3404 > new_slab mm/slub.c:3447 [inline] > ___slab_alloc+0x160/0x930 mm/slub.c:4485 > __slab_alloc_node mm/slub.c:4549 [inline] > slab_alloc_node mm/slub.c:4925 [inline] > __do_kmalloc_node mm/slub.c:5331 [inline] > __kmalloc_noprof+0x140/0x7b0 mm/slub.c:5345 > _kmalloc_noprof include/linux/slab.h:973 [inline] > _kzalloc_noprof include/linux/slab.h:1286 [inline] > __alloc_empty_sheaf mm/slub.c:2774 [inline] > alloc_empty_sheaf mm/slub.c:2794 [inline] > init_percpu_sheaves mm/slub.c:7555 [inline] > do_kmem_cache_create+0x8ae/0x9a0 mm/slub.c:8595 > create_boot_cache+0xbf/0x120 mm/slab_common.c:717 > create_kmalloc_cache+0x41/0xb0 mm/slab_common.c:735 > new_kmalloc_cache+0xd4/0x180 mm/slab_common.c:982 > create_kmalloc_caches+0x14/0x50 mm/slab_common.c:1005 > kmem_cache_init+0x14a/0x1e0 mm/slub.c:8496 > mm_core_init+0x7e/0xb0 mm/mm_init.c:2728 > start_kernel+0x162/0x3e0 init/main.c:1034 > x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 > x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 > common_startup_64+0x13e/0x157 > > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:__ClearPagePrezeroed include/linux/page-flags.h:682 [inline] > RIP: 0010:post_alloc_hook+0x287/0x310 mm/page_alloc.c:1863 > Code: ff ff 89 da be 01 00 00 00 48 c7 c7 40 50 4f 8e e8 ce 4b d4 02 e9 c5 fe ff ff 4c 89 ef 48 c7 c6 40 ef 7a 8b e8 2a c6 05 ff 90 <0f> 0b 31 ed f7 44 24 04 00 01 00 00 0f 84 8e fd ff ff e9 86 fd ff > RSP: 0000:ffffffff8e0078e0 EFLAGS: 00010046 > RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff8e0fef40 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 > R10: dffffc0000000000 R11: ffffed10170c4903 R12: dffffc0000000000 > R13: ffffea0004ff8e00 R14: 1ffffd40009ff1c0 R15: 0000000000000000 > FS: 0000000000000000(0000) GS:ffff888125a79000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffff88823ffff000 CR3: 000000000e1b8000 CR4: 00000000000100b0 > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup