From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f70.google.com (mail-ot1-f70.google.com [209.85.210.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DDDB23F1073 for ; Fri, 9 Oct 2026 05:53:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791525206; cv=none; b=gEq2Fjk55aBZdFzCecE2g5LcTHt0MvX0LF3H9/VSuYAWu5VlsTfEA2XqIDseAm3LKX6RmXCBw++HZOC6fODsp8RRvI+labyDG4VP4YQ22nrWJczQ2QiCLLDBwVrAZICiCWVRb7RATqjqTm9HTkX6B0ZgeAL0DcLRSBJjGMxRWSk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791525206; c=relaxed/simple; bh=io/4IKNtEDA2/qvWB2ZPzzWfvdGJiZfVEQAOr1a159c=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=qQSienTr3I622a5xvisROlLId9lvExfPT7UoS7y23o2ZSKGfHxBFSF4A2NVlJF9eXOKO75RleuntdFJXvRdP7WvjCIpExdaapv+tK2g+5MZ/giBY8lGXPWkafKitVF9u/i40rZYvMgGFRaBgS3/4awF5OVbqoUBeQxr0rshDsnE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.210.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-ot1-f70.google.com with SMTP id 46e09a7af769-80a79b0de9eso12226518a34.2 for ; Thu, 08 Oct 2026 22:53:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791525204; x=1792130004; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=kKKvmFfZwsqrfM3PYHPrEGRSmIXlY77Q19PAO1JkExw=; b=EQ5JGCoUSYxWcqyCU5gQjo0xA9tzvaAoGEBT3O7XN86SivVbLLvV/2SRtZHnldL5c/ b54LTcPYvV72p8OhiALf+etaEhkTkvwi+B1uPiYoBoNxApasmCDPx9mTOw9iJbtJ+3O0 9cXp4u0GF3CfU1kZ3XQvT6jLa5Hl2qr3jaDCRMqXLMAPd7CFPSKqq6/W6k4qlbRJgGCh CUOJW1nA32O4kXOfB8+kkCNnpGeds82qMw5mxrn2XXb+T9ADFnoeDNvejbgniRCwugLH lHCGmoXXYq/sDcm5wc5AnD4AsIITSq2Ah0gpKmiAlR5orVFjQCHgGNnbvDIIH7fLcGlO dPMg== X-Forwarded-Encrypted: i=1; AKwUvBx5u5riTARCjBCrSdy4muC5ibJErgMLIobExOZA3mkocJSBdSH15ma9RglTATlK7syN3Ru1kxzxXirtbX4=@vger.kernel.org X-Gm-Message-State: AFuF++lUnwpjKJtBcVM3bmS6ZtgMYrgqMyPfvTB+BpUObt198EnmtRiE Q0O6faW1OwbfANblbrrHzQ0lKNfdsGlBgSFnm1uBZhyamdvaE9nJrs2minuiwLrd57mqCRJFMY5 +KYLeWoubQjrqO0QqvwW7VSugy2bJzmG2ELj5QiMoQIuALs/TSE2tjYeEp/I= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:50a2:b0:4e8:bce4:9924 with SMTP id 5614622812f47-50c53c99978mr811082b6e.25.1791525203840; Thu, 08 Oct 2026 22:53:23 -0700 (PDT) Date: Thu, 08 Oct 2026 22:53:23 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6ac88153.bbc4c7f9.15faa7.000d.GAE@google.com> Subject: [syzbot] [nfs?] KASAN: slab-use-after-free Read in add_to_unconfirmed From: syzbot To: Dai.Ngo@oracle.com, cel@kernel.org, jlayton@kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, neil@brown.name, okorniev@redhat.com, syzkaller-bugs@googlegroups.com, tom@talpey.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 6addb4f38557 Merge tag 'edac_urgent_for_v7.3_rc6' of git:/.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=113b17f5580000 kernel config: https://syzkaller.appspot.com/x/.config?x=23e5acac5c98285f dashboard link: https://syzkaller.appspot.com/bug?extid=9c7b9c5f6dd1d470b605 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/484fafd2304b/disk-6addb4f3.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/3a897e82997f/vmlinux-6addb4f3.xz kernel image: https://storage.googleapis.com/syzbot-assets/57fc9f6de4c3/bzImage-6addb4f3.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9c7b9c5f6dd1d470b605@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in list_add include/linux/list.h:192 [inline] BUG: KASAN: slab-use-after-free in add_to_unconfirmed+0x367/0x8c0 fs/nfsd/nfs4state.c:3993 Read of size 8 at addr ffff888076b91860 by task nfsd/7883 CPU: 0 UID: 0 PID: 7883 Comm: nfsd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 list_add include/linux/list.h:192 [inline] add_to_unconfirmed+0x367/0x8c0 fs/nfsd/nfs4state.c:3993 nfsd4_exchange_id+0xc21/0x1350 fs/nfsd/nfs4state.c:4407 nfsd4_proc_compound+0x145a/0x25b0 fs/nfsd/nfs4proc.c:3313 nfsd_dispatch+0x33d/0x9b0 fs/nfsd/nfssvc.c:1038 svc_process_common+0x1173/0x18c0 net/sunrpc/svc.c:1527 svc_process+0x290/0x710 net/sunrpc/svc.c:1682 svc_handle_xprt net/sunrpc/svc_xprt.c:886 [inline] svc_recv+0x2525/0x3280 net/sunrpc/svc_xprt.c:968 nfsd+0x3a5/0xbb0 fs/nfsd/nfssvc.c:919 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 7644: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x321/0x600 mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] nfs4_state_create_net fs/nfsd/nfs4state.c:9736 [inline] nfs4_state_start_net+0x10c/0x1180 fs/nfsd/nfs4state.c:9834 nfsd_startup_net fs/nfsd/nfssvc.c:391 [inline] nfsd_svc+0x481/0x710 fs/nfsd/nfssvc.c:775 write_threads+0x434/0x610 fs/nfsd/nfsctl.c:438 nfsctl_transaction_write+0x10f/0x160 fs/nfsd/nfsctl.c:114 vfs_write+0x296/0xba0 fs/read_write.c:685 ksys_write+0x150/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6123: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6509 [inline] kfree+0x1c5/0x650 mm/slub.c:6802 nfs4_state_destroy_net fs/nfsd/nfs4state.c:9823 [inline] nfs4_state_shutdown_net+0x774/0xa00 fs/nfsd/nfs4state.c:9908 nfsd_shutdown_net fs/nfsd/nfssvc.c:421 [inline] nfsd_destroy_serv+0x25d/0x450 fs/nfsd/nfssvc.c:534 nfsd_shutdown_threads+0x8c/0xd0 fs/nfsd/nfssvc.c:591 nfsd_umount+0x41/0x60 fs/nfsd/nfsctl.c:1372 deactivate_locked_super+0xbe/0x110 fs/super.c:586 cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888076b91800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 96 bytes inside of freed 256-byte region [ffff888076b91800, ffff888076b91900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888076b90000 pfn:0x76b90 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801b041b40 ffffea0001e86410 ffffea00014c3b90 raw: ffff888076b90000 000000000010000a 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801b041b40 ffffea0001e86410 ffffea00014c3b90 head: ffff888076b90000 000000000010000a 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5615, tgid 5615 (syz-executor), ts 88616580147 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab+0x7d/0x620 mm/slub.c:3462 new_slab mm/slub.c:3513 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7418 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x47b/0x720 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] new_dir fs/proc/proc_sysctl.c:965 [inline] get_subdir fs/proc/proc_sysctl.c:1009 [inline] sysctl_mkdir_p fs/proc/proc_sysctl.c:1319 [inline] __register_sysctl_table+0xc02/0x1370 fs/proc/proc_sysctl.c:1394 neigh_sysctl_register+0x9b1/0xa90 net/core/neighbour.c:3932 devinet_sysctl_register+0xad/0x200 net/ipv4/devinet.c:2782 inetdev_init+0x29e/0x4d0 net/ipv4/devinet.c:291 inetdev_event+0x307/0x15e0 net/ipv4/devinet.c:1590 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline] call_netdevice_notifiers net/core/dev.c:2327 [inline] register_netdevice+0x18a4/0x1eb0 net/core/dev.c:11584 macvlan_common_newlink+0x12e5/0x1a50 drivers/net/macvlan.c:1575 rtnl_newlink_create+0x305/0x7b0 net/core/rtnetlink.c:3974 page last free pid 5615 tgid 5615 ts 88569600911 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962 __slab_free+0x274/0x2c0 mm/slub.c:5823 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_node_noprof+0x354/0x610 mm/slub.c:5068 __alloc_skb+0x1db/0x7a0 net/core/skbuff.c:704 alloc_skb include/linux/skbuff.h:1384 [inline] nlmsg_new include/net/netlink.h:1055 [inline] netlink_ack+0x136/0xb30 net/netlink/af_netlink.c:2512 netlink_rcv_skb+0x2a4/0x4a0 net/netlink/af_netlink.c:2581 netlink_unicast_kernel net/netlink/af_netlink.c:1338 [inline] netlink_unicast+0x7bd/0x940 net/netlink/af_netlink.c:1364 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] __sys_sendto+0x408/0x5a0 net/socket.c:2281 __do_sys_sendto net/socket.c:2288 [inline] __se_sys_sendto net/socket.c:2284 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2284 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888076b91700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888076b91780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888076b91800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888076b91880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888076b91900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== --- 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