From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f79.google.com (mail-oo1-f79.google.com [209.85.161.79]) (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 9E8DA3FE65F for ; Wed, 29 Apr 2026 17:36:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777484198; cv=none; b=WNK6bVFLl270vaTN+lK5NVbtG45eZpdNw/UxkL9TSX8gRT6nTIoK7yJwkosS/HCoB/crRsHuhNlw91ZoVfbLM9gWjnefq0xTJa5jt3ujIyAtJjgVJU+Nd6xjVsBvp/+dOX7OSeh0i4vnF2I9t03/wd0ui0rIXW4nl4rPbcTlLw4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777484198; c=relaxed/simple; bh=v/0FuhxSOlB7X4gFO1zbOE+jds6nP3Qq+6THCLjS2Zw=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=ASF8KB45/TlOF7XU1AEz7/AC90pVQTRGHWMJj1LhgldX0xbl+YayufQgUoDB7/UR07DKe+AOk/z4YsN1s3PBOsDv1VByxJ9N7qd5V2NtBb6VkLPP+L8PUwi2qSSrxwbUoGIYlvAP2MNSyBVRJNbjXpYGEEvNnKEsl/rNS84EUCM= 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=209.85.161.79 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-f79.google.com with SMTP id 006d021491bc7-696233b2816so162640eaf.1 for ; Wed, 29 Apr 2026 10:36:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777484195; x=1778088995; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=jiHUm98BDxZ3jihx0YOQdOmpKJWU+yfzKGqWIOvP2+0=; b=f+mvP7onQ6g21aPhFzuNFPLHEX93bToNg894nXmexpwj0UvzuiK7u5somKapsko1me mqwc2Ui4cgak6Ml+/y9h/FlW7CtUlJimd5qgYAb/uO+XUxf+/OOgHcIknUT2JwbcPL9g m8vrebaSjZWhB+uFvPFLT3Dt7ELjZIQn57rn+VChhFi8vbo56hgdATBtw/MGom0QyJsq ftUsK3q3DJCTomsq14Lrlb/6z/OA4hwD+zhgDmpwRzk1I2U/sEqW/S6djK5tAtoL9H4m iMrPjaIB8nNoF9PU+u7AvpzcYpwM0tu14YlyFLdqBiOyI2a/BkxH/DCawoLnbM9zDmxC uU8g== X-Forwarded-Encrypted: i=1; AFNElJ/3Nt+0PjGF0JgEutDG3Xp79M+1jW0vsZ4+/B1Cf7OEe2p98k+OYTTZKdbUIlkaMrNUP/I72A8jUzC873g=@vger.kernel.org X-Gm-Message-State: AOJu0Yw0FRAO6N+/XUGIQukjdshbm+SA5e3NumLieswViHVjVT4z9cNO nQk185sYwN0BfCfcggUhZBxZuv+6sIdCUl0jE+InTN3uvLTNHggE4r+txsCg+1sOQJ7mnaCliTE H28MO+RU+xCwuuu0ruMc8GviKQvfQdm89Wphi4du0QnlW3L01AVDbx/oZsMs= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2908:b0:694:99e1:62fc with SMTP id 006d021491bc7-6965cb5bffemr4338246eaf.41.1777484195616; Wed, 29 Apr 2026 10:36:35 -0700 (PDT) Date: Wed, 29 Apr 2026 10:36:35 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69f241a3.170a0220.3c4978.0005.GAE@google.com> Subject: [syzbot] [mm?] WARNING: bad unlock balance in finish_fault From: syzbot To: Liam.Howlett@oracle.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, shakeel.butt@linux.dev, surenb@google.com, syzkaller-bugs@googlegroups.com, vbabka@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 897d54018cc9 Merge tag 'fbdev-for-7.1-rc1-2' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=158df1ba580000 kernel config: https://syzkaller.appspot.com/x/.config?x=59da38148f3a3d24 dashboard link: https://syzkaller.appspot.com/bug?extid=8caf74f5399ee2d5212b compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-897d5401.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/20848bcda8fe/vmlinux-897d5401.xz kernel image: https://storage.googleapis.com/syzbot-assets/2351a3d1bb73/bzImage-897d5401.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+8caf74f5399ee2d5212b@syzkaller.appspotmail.com ===================================== WARNING: bad unlock balance detected! syzkaller #0 Not tainted ------------------------------------- cmp/5659 is trying to release lock (rcu_read_lock) at: [] rcu_read_unlock+0x2d/0xb0 include/linux/rcupdate.h:867 but there are no more locks to release! other info that might help us debug this: 1 lock held by cmp/5659: #0: ffff88803accd848 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x11d/0x590 mm/mmap_lock.c:310 stack backtrace: CPU: 2 UID: 0 PID: 5659 Comm: cmp 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 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_unlock_imbalance_bug.part.0+0xfb/0x106 kernel/locking/lockdep.c:5298 print_unlock_imbalance_bug kernel/locking/lockdep.c:5278 [inline] __lock_release kernel/locking/lockdep.c:5537 [inline] lock_release kernel/locking/lockdep.c:5889 [inline] lock_release+0x28d/0x310 kernel/locking/lockdep.c:5875 rcu_read_unlock+0x32/0xb0 include/linux/rcupdate.h:867 pte_unmap include/linux/pgtable.h:117 [inline] finish_fault+0x8ed/0x1400 mm/memory.c:5763 do_cow_fault mm/memory.c:5935 [inline] do_fault+0xff2/0x1750 mm/memory.c:6029 do_pte_missing mm/memory.c:4550 [inline] handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault+0x187d/0x2a00 mm/memory.c:6549 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718 do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7fd47fe2aff2 Code: 0f 60 c0 66 0f 61 c0 66 0f 70 c0 00 48 83 fa 10 72 76 48 83 fa 20 77 12 0f 11 44 17 f0 0f 11 07 c3 0f 11 47 e0 0f 11 47 f0 c3 <0f> 11 07 0f 11 47 10 48 01 d7 48 83 fa 40 76 e7 0f 11 40 20 0f 11 RSP: 002b:00007ffcb5d4bcd8 EFLAGS: 00010206 RAX: 00007fd47fb30068 RBX: 0000000000000004 RCX: 00007fd47fb326d0 RDX: 0000000000000f98 RSI: 0000000000000000 RDI: 00007fd47fb30068 RBP: 00007ffcb5d4c0a0 R08: 00007fd47fb30068 R09: 0000000000000003 R10: 0000000000000812 R11: 00007ffcb5d4c188 R12: 00007ffcb5d4bd88 R13: 00007fd47fdffab0 R14: 00007ffcb5d4c140 R15: 00007fd47fb31000 ------------[ cut here ]------------ rrln < 0 || rrln > RCU_NEST_PMAX WARNING: kernel/rcu/tree_plugin.h:443 at __rcu_read_unlock kernel/rcu/tree_plugin.h:443 [inline], CPU#2: cmp/5659 WARNING: kernel/rcu/tree_plugin.h:443 at __rcu_read_unlock+0x235/0x5e0 kernel/rcu/tree_plugin.h:430, CPU#2: cmp/5659 Modules linked in: CPU: 2 UID: 0 PID: 5659 Comm: cmp 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:__rcu_read_unlock kernel/rcu/tree_plugin.h:443 [inline] RIP: 0010:__rcu_read_unlock+0x235/0x5e0 kernel/rcu/tree_plugin.h:430 Code: 74 11 c7 45 58 01 00 00 00 bf 09 00 00 00 e8 c2 6f da ff e8 9d ff 22 00 9c 58 f6 c4 02 0f 85 dd 02 00 00 fb e9 57 fe ff ff 90 <0f> 0b 90 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc e8 54 76 88 RSP: 0000:ffffc90003a27b28 EFLAGS: 00010286 RAX: 00000000ffffffff RBX: ffff888029db4a00 RCX: ffffffff81e7b7ae RDX: 0000000000000000 RSI: ffffffff8def8e2a RDI: ffff888029db4ec4 RBP: ffff88802bdd4980 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000080000000 R11: 0000000000000012 R12: ffff88802bf53d40 R13: ffffc90003a27d58 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880d6579000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd47fb30068 CR3: 000000003585a000 CR4: 0000000000352ef0 Call Trace: pte_unmap include/linux/pgtable.h:117 [inline] finish_fault+0x8ed/0x1400 mm/memory.c:5763 do_cow_fault mm/memory.c:5935 [inline] do_fault+0xff2/0x1750 mm/memory.c:6029 do_pte_missing mm/memory.c:4550 [inline] handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault+0x187d/0x2a00 mm/memory.c:6549 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718 do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7fd47fe2aff2 Code: 0f 60 c0 66 0f 61 c0 66 0f 70 c0 00 48 83 fa 10 72 76 48 83 fa 20 77 12 0f 11 44 17 f0 0f 11 07 c3 0f 11 47 e0 0f 11 47 f0 c3 <0f> 11 07 0f 11 47 10 48 01 d7 48 83 fa 40 76 e7 0f 11 40 20 0f 11 RSP: 002b:00007ffcb5d4bcd8 EFLAGS: 00010206 RAX: 00007fd47fb30068 RBX: 0000000000000004 RCX: 00007fd47fb326d0 RDX: 0000000000000f98 RSI: 0000000000000000 RDI: 00007fd47fb30068 RBP: 00007ffcb5d4c0a0 R08: 00007fd47fb30068 R09: 0000000000000003 R10: 0000000000000812 R11: 00007ffcb5d4c188 R12: 00007ffcb5d4bd88 R13: 00007fd47fdffab0 R14: 00007ffcb5d4c140 R15: 00007fd47fb31000 --- 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