From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f69.google.com (mail-oo1-f69.google.com [209.85.161.69]) (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 217423C1A for ; Sat, 15 Aug 2026 00:22:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786753325; cv=none; b=Rh2O0Aa1Ei0YKX9Y88u7XykNxntxNpnbgUMSFYCOTAtE4d0SfhrVzTIF2ynqnRC71FlxXLSoQM1rkQG1ldhV7LA9jtAgaVNBIFfOO+LqeNQ3a+H+NT5J8vv4qPqXcdlI3VAYYGBDVBtdCgWz6w1OQfYXogn467HLR03NZZCtIgU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786753325; c=relaxed/simple; bh=kenWsqjznF+en2f557rhfAqbZeHVWIK5bHPUk08S1FI=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=VPpLSp/wGwiIbQVc2gvEcXUWyS5pAi0M3bRoRcbOR/sVuMDNx5GbEaN5K9KxPMkvMsqYCbLn6HhaPM2Kf5j/JaA6ez35nMPN89ZiCA9YVLfSlGzc2S2t29KfqQXk67l3/F2BSI3KbGT9GCQjMNSLS8Rfaiy8ZZxLApIFS+bxjRY= 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=209.85.161.69 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-oo1-f69.google.com with SMTP id 006d021491bc7-6ae934cbe4fso1449109eaf.1 for ; Fri, 14 Aug 2026 17:22:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786753323; x=1787358123; h=content-type:to:from:subject:message-id:in-reply-to:date :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=Z5+LtH2Sz8FQM+4b/sLaZ6YfBlRhpBHqfpVco3M5Gj0=; b=psZgMNbpy1dM5gWy7s6/2YWCDQJ6G00Rg5+3Mfhwad6EVmPMFa7y+mBOyTjnjq+anW lNT4Eyc7xoM2SQqYRiNwTOXsBPgm5/+myBCrxNb9hCARckJN7ZusSY7AVvaflCvrBkFX 8SfarNksBXjr0DOtFOXJ9YalygfYpVR8WKJAO2lxWusmXrd0oWkg/75GOcccM2cjVc3P KCOqtfa4ZVe4jLp1FuUxG1gsYNjJDSbCbYjZcvaSoLbzrI3OjZAkzEv30fILTcundxNo gSOOl8wlaanYPXSDGKL6SOuZLaFdzu4qb5Eu67Qpe+9A70YgPzB3XREo3S66WSF0ZV7C MvzQ== X-Forwarded-Encrypted: i=1; AHgh+RqeqCZunMqGLOtBWaTGPlvgOcfjny5bCw9UfkZJdgOZjelnrQ+bvTDXUXFqI9+6cQARMeToNb+xQHU4RMU=@vger.kernel.org X-Gm-Message-State: AOJu0YxLAg4hEO3CHJxYqP/51j+8JA3vxOZjhkb3QEKcMxvmyHPFtbqL YIk6YobnfV8PkR3mZfKwiGk04Sok+tK6fNU6brlEUk6XW/Zuz7ITzhrLgyLWzD96YUHAiz8deHy 9nFO9gLVJFOoJDtMGiLDU4PRwsKdyMl5gWAz4e6DJHyILqWObjZLBIVKbCE4= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:4ccc:b0:6a3:7341:f6ed with SMTP id 006d021491bc7-6b0d5fca9famr8087324eaf.1.1786753323076; Fri, 14 Aug 2026 17:22:03 -0700 (PDT) Date: Fri, 14 Aug 2026 17:22:03 -0700 In-Reply-To: <20260815000715.1133-1-hdanton@sina.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7fb12b.f7a79266.2f965f.0006.GAE@google.com> Subject: Re: [syzbot] [net?] WARNING: refcount bug in new_device_store From: syzbot To: hdanton@sina.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: WARNING: refcount bug in new_device_store kobject: kobject_add_internal failed for netdevsim1 (error: -12 parent: devices) ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x111/0x130 lib/refcount.c:25, CPU#1: syz-executor115/6024 Modules linked in: CPU: 1 UID: 0 PID: 6024 Comm: syz-executor115 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:refcount_warn_saturate+0x111/0x130 lib/refcount.c:25 Code: cc e8 d3 91 ec fc 48 8d 3d bc c2 0e 0c 67 48 0f b9 3a e8 c2 91 ec fc 5b 5d e9 9b 52 a0 06 e8 b6 91 ec fc 48 8d 3d af c2 0e 0c <67> 48 0f b9 3a e8 a5 91 ec fc 5b 5d e9 7e 52 a0 06 48 89 df e8 56 RSP: 0018:ffffc90003857b80 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffffffff9ba33900 RCX: ffffffff851de11b RDX: ffff888033d14a80 RSI: ffffffff851de1ca RDI: ffffffff912ca480 RBP: 0000000000000002 R08: 0000000000000005 R09: 0000000000000004 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000005 R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000001 FS: 000055555bbf3400(0000) GS:ffff8880d5ee9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055ec5148bda8 CR3: 000000005556e000 CR4: 0000000000352ef0 Call Trace: __refcount_add include/linux/refcount.h:289 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] new_device_store+0x682/0x700 drivers/net/netdevsim/bus.c:197 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_pwrite64 fs/read_write.c:794 [inline] __do_sys_pwrite64 fs/read_write.c:802 [inline] __se_sys_pwrite64 fs/read_write.c:799 [inline] __x64_sys_pwrite64+0x1eb/0x250 fs/read_write.c:799 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1cc06cd237 Code: 48 89 fa 4c 89 df e8 98 1d 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffdcb4b35c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 000055555bbf3400 RCX: 00007f1cc06cd237 RDX: 0000000000000005 RSI: 00007f1cc07060cd RDI: 0000000000000004 RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 R13: 00007ffdcb4b3610 R14: 0000000000000007 R15: 00007f1cc07064c2 ---------------- Code disassembly (best guess): 0: cc int3 1: e8 d3 91 ec fc call 0xfcec91d9 6: 48 8d 3d bc c2 0e 0c lea 0xc0ec2bc(%rip),%rdi # 0xc0ec2c9 d: 67 48 0f b9 3a ud1 (%edx),%rdi 12: e8 c2 91 ec fc call 0xfcec91d9 17: 5b pop %rbx 18: 5d pop %rbp 19: e9 9b 52 a0 06 jmp 0x6a052b9 1e: e8 b6 91 ec fc call 0xfcec91d9 23: 48 8d 3d af c2 0e 0c lea 0xc0ec2af(%rip),%rdi # 0xc0ec2d9 * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: e8 a5 91 ec fc call 0xfcec91d9 34: 5b pop %rbx 35: 5d pop %rbp 36: e9 7e 52 a0 06 jmp 0x6a052b9 3b: 48 89 df mov %rbx,%rdi 3e: e8 .byte 0xe8 3f: 56 push %rsi Tested on: commit: dac3e89a Merge tag 'drm-fixes-2026-08-15' of https://g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13452949580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307 dashboard link: https://syzkaller.appspot.com/bug?extid=989ff6506f5c6d1ff56b compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 patch: https://syzkaller.appspot.com/x/patch.diff?x=1339d279580000