From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f206.google.com (mail-oi1-f206.google.com [209.85.167.206]) (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 8B86330C15C for ; Wed, 12 Aug 2026 00:22:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786494158; cv=none; b=CzTcfEi4ZTgzSOkCKB70U171axcOUNqhS5ljlzGnkoYKonCuN+f10R42rCYuGc5aqsLOBLNxXCiqCXpwQogS24dcL0MolH/kWgbJEhKFb6bLh71Gpz4keJoYOGlTWcK7XTAGk5a077lwfYEp2DjZX/E1nh3fpuxrXWuqCPEBVvo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786494158; c=relaxed/simple; bh=208QMu+OsTyZ3BSoitdxeWdPz87VNPqm5tyxEbhVBCU=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=kpLhBGEauHTj04R8UPisISI4j0EKF7OydbHlrCiUwwmamvwLtRXFUZFT4KeNAV8O2RCFxdQJWpCqdSbLQ2chiYnpzgbxBC4ixMGisYA7miTumZFCjiscT0JQFDjsfegxFbbCmYxyB9l8mU3SbJc3oVSs8ad9Q2VILdxn+2JPx3g= 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=209.85.167.206 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-oi1-f206.google.com with SMTP id 5614622812f47-4b1bd8320ecso366249b6e.3 for ; Tue, 11 Aug 2026 17:22:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786494155; x=1787098955; 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=nMAcU0Te/6B7srJdAbN55W1Loj4vijaSz1wl3sGVswY=; b=F2DxV0Ya/pfKpBOj/6u5JA/DHOidf2o5cAvz7R0m2drO0U0OtNwAFAOscosvFhQXeO 7C0AkaTSP+bVK1Uy91p0fnpM3FvyjmOhcxn8Pw3IQdeB1xJ9WpK6SJCRUZVEwPbwRc5u yat90rA+zq+4Ro/pGHPHBIy4oNiGyLOr4rOkx8n8zy90dC6qprNUoANinblmzAeHwSmd TdyfDS2/61UfTkeYr8bhKBuUCwnmRGnrJCRTDiiZNA9UAilUfvg2vRum1wTpIup3nYYT pE5Hpe8lJypeuOuBqBrlLFRROCQl4cjyJP6qNT5tIOMc9/FJCzdgV6IYr5s2wfGGaNnb zF5A== X-Forwarded-Encrypted: i=1; AHgh+RoZiFk7IPas70qTHBt3XVAZ4ApA9aoIZZ6Tb7WNoxNO9xw4rpnacJRrjba+R9cbfcigbzRuW5+9RRxyzFM=@vger.kernel.org X-Gm-Message-State: AOJu0YwlxpEIOZxIh1OO4IwJRHvODzklhwAvudxOdbH9W55cafCXq8mI TENhSOj3j3/TmsTSsAf8klxzrH/S3xfOetWaGS5O57wM5NC2ig0FnSQ/JOv1O8NNhbveknHAl17 ICt42AhUZypaf0b3ieTApyYnM4qJLCjIyo2Ood4luwG02aUcAC5/5mk2sMNE= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:2389:b0:497:d1e7:5e90 with SMTP id 5614622812f47-4b210bb5798mr1075518b6e.18.1786494155514; Tue, 11 Aug 2026 17:22:35 -0700 (PDT) Date: Tue, 11 Aug 2026 17:22:35 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7bbccb.ac361c09.22ff0a.0048.GAE@google.com> Subject: [syzbot] [io-uring?] [net?] WARNING: refcount bug in zcrx_unregister_user From: syzbot To: asml.silence@gmail.com, axboe@kernel.dk, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: ea2bff00da89 Add linux-next specific files for 20260806 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=10e27e49580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b2f9169913eb6d73 dashboard link: https://syzkaller.appspot.com/bug?extid=a43f81e0646c5bbd2b88 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10d92132580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/473ce49245bc/disk-ea2bff00.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/4d5bfcd186f5/vmlinux-ea2bff00.xz kernel image: https://storage.googleapis.com/syzbot-assets/281694927321/bzImage-ea2bff00.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a43f81e0646c5bbd2b88@syzkaller.appspotmail.com ------------[ cut here ]------------ refcount_t: decrement hit 0; leaking memory. WARNING: lib/refcount.c:31 at refcount_warn_saturate+0x70/0x110 lib/refcount.c:31, CPU#0: syz.0.17/5808 Modules linked in: CPU: 0 UID: 0 PID: 5808 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:refcount_warn_saturate+0x70/0x110 lib/refcount.c:31 Code: c6 c0 fe 36 8f e8 90 e5 ee fc 83 fb 01 7e 22 83 fb 02 74 39 83 fb 03 74 47 83 fb 04 75 68 e8 f7 df ee fc 48 8d 3d b0 16 8b 0b <67> 48 0f b9 3a eb 66 85 db 74 3e 83 fb 01 75 4c e8 db df ee fc 48 RSP: 0018:ffffc900032d78c8 EFLAGS: 00010293 RAX: ffffffff84d8a429 RBX: 0000000000000004 RCX: ffff888032abddc0 RDX: 0000000000000000 RSI: ffffffff8f36fec0 RDI: ffffffff9063bae0 RBP: ffffc900032d7a10 R08: ffff888032abddc0 R09: 0000000000000005 R10: 0000000000000004 R11: 0000000000000000 R12: ffff8880353d2700 R13: dffffc0000000000 R14: ffff8880353d2744 R15: 0000000000000001 FS: 00005555674e4500(0000) GS:ffff888124f12000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000002020 CR3: 0000000079e90000 CR4: 00000000003526f0 Call Trace: __refcount_dec include/linux/refcount.h:461 [inline] refcount_dec include/linux/refcount.h:476 [inline] ref_tracker_free+0x706/0x830 lib/ref_tracker.c:303 netdev_tracker_free include/linux/netdevice.h:4545 [inline] netdev_put include/linux/netdevice.h:4562 [inline] io_close_queue io_uring/zcrx.c:582 [inline] zcrx_unregister_user+0x2d8/0x430 io_uring/zcrx.c:681 zcrx_unregister io_uring/zcrx.c:688 [inline] io_register_zcrx+0x875/0xc00 io_uring/zcrx.c:1021 __io_uring_register io_uring/register.c:942 [inline] __do_sys_io_uring_register io_uring/register.c:1040 [inline] __se_sys_io_uring_register+0xc23/0x1ab0 io_uring/register.c:1017 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x510 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa6a959e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe56af7168 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab RAX: ffffffffffffffda RBX: 00007fa6a9825fa0 RCX: 00007fa6a959e0d9 RDX: 0000200000000100 RSI: 0000000000000020 RDI: 0000000000000003 RBP: 00007fa6a9635024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa6a9825fac R14: 00007fa6a9825fa0 R15: 00007fa6a9825fa0 ---------------- Code disassembly (best guess), 5 bytes skipped: 0: e8 90 e5 ee fc call 0xfceee595 5: 83 fb 01 cmp $0x1,%ebx 8: 7e 22 jle 0x2c a: 83 fb 02 cmp $0x2,%ebx d: 74 39 je 0x48 f: 83 fb 03 cmp $0x3,%ebx 12: 74 47 je 0x5b 14: 83 fb 04 cmp $0x4,%ebx 17: 75 68 jne 0x81 19: e8 f7 df ee fc call 0xfceee015 1e: 48 8d 3d b0 16 8b 0b lea 0xb8b16b0(%rip),%rdi # 0xb8b16d5 * 25: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2a: eb 66 jmp 0x92 2c: 85 db test %ebx,%ebx 2e: 74 3e je 0x6e 30: 83 fb 01 cmp $0x1,%ebx 33: 75 4c jne 0x81 35: e8 db df ee fc call 0xfceee015 3a: 48 rex.W --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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