From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f70.google.com (mail-oa1-f70.google.com [209.85.160.70]) (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 EC3932C3268 for ; Mon, 9 Feb 2026 14:46:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770648364; cv=none; b=dj71olqQ0XlVVVIiKIscbfff2dodnGjpIuzub7S0Ggxby8HiO9UA/VI5lrFq5U4+HJXKfaaFvhHUZLz9LGRCPRPMLdYtMnEml9AIhsHpSlv3jJHnsimvQxcv55EweK0c2LMXYpvBExB9d6KXeRjAnbEVXbUgc7Z3xxZbnGDglAY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770648364; c=relaxed/simple; bh=tkmXxYJBFax+xQRXOFaj5zZm4BYWqxkJLHxgSC5eV00=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=azKlhUfAsL5tSJTNRtS/advvwraXfmHQoSUJxzx9mlTLZD3PL1GJaDIanAcAfqpUvZUXng/iWgYwH74aQuYjFAdYhgALTRLVrAPVpfsyVTcWei9kV5xpFhcs0fccKmnwphXa7ENS3MBZXkQloxbWMPMls32UhgGoofR9JV3dsEU= 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=209.85.160.70 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-oa1-f70.google.com with SMTP id 586e51a60fabf-40948b7e832so22200454fac.0 for ; Mon, 09 Feb 2026 06:46:03 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770648362; x=1771253162; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=guiQQb7wK6JyprPXAP3wS+UiXuA9GNyz56UBe4jMXZ0=; b=CY0O36IS/0Tn6U6ygXaWMnwEu+LkKCH1TX4o1Xh9Wz7jOoi+oNNTImHiwGXHyZ8pnT jzS+5SgxU6rnvWgpiA+SseCsnt9OVsldyK8jI8AiHBB2O0HXxMzGVYVFya7S5Z/HMm68 NxfyB0IaIVrUpJqZysX8ZCINJWwUiNKSMRQWqMef/FtxlxZYywGraninCAwCsb6nTkdp RNKoUci/DemphUQgEdC2ZZyvKFWw8Yn/I25R0L5RClbzu8gjvHCcNzU0eqNiKGL6JBC+ kRMhpYEG7YmUoNV7r85US6u8FQTFtP4dmUI8UaZ8feykSpHP2+F7kd2t6eVNiBkcMVPw sO/Q== X-Forwarded-Encrypted: i=1; AJvYcCUHV0SVVKNwxgDq2IjY/NeicVHldXG2ATCpvNvI5JbK5tGODx4Wd1oN6/g5Iyj3wWb/lMRVp2WZWyB8Dpk=@vger.kernel.org X-Gm-Message-State: AOJu0YzBOT+F3R1UL/V1ViWRCKrPNhv5L4tpsXelqF3e5Qn0OtBX3UVq RhYD3oJW5K44kXW4P3cwA59RoukdPFaItA18WjZeuH6oLMh/Z+Vk/QDhGwhXEPexn1VWU48NaI3 VFSATHkFFJkpEKuntFjcpCCXC9NA5xmw1Os+CQXQ6FOVvkAOI+nJwPEJXAk4= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1808:b0:662:fa52:9302 with SMTP id 006d021491bc7-66d0a093d47mr5149217eaf.23.1770648362548; Mon, 09 Feb 2026 06:46:02 -0800 (PST) Date: Mon, 09 Feb 2026 06:46:02 -0800 In-Reply-To: <20260209142936.18000-1-activprithvi@gmail.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6989f32a.050a0220.3b3015.0072.GAE@google.com> Subject: Re: [syzbot] [fs?] possible deadlock in __configfs_open_file From: syzbot To: activprithvi@gmail.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: possible deadlock in __configfs_open_file ============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz.0.17/6458 is trying to acquire lock: ffff88802836c678 (&p->frag_sem){.+.+}-{4:4}, at: __configfs_open_file+0xe8/0x9c0 fs/configfs/file.c:304 but task is already holding lock: ffff88802836c678 (&p->frag_sem){.+.+}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline] ffff88802836c678 (&p->frag_sem){.+.+}-{4:4}, at: configfs_write_iter+0x218/0x4c0 fs/configfs/file.c:229 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&p->frag_sem); lock(&p->frag_sem); *** DEADLOCK *** May be due to missing lock nesting notation 5 locks held by syz.0.17/6458: #0: ffff888078dc50b8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1255 #1: ffff88801cbe4420 (sb_writers#12){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #2: ffff888032363888 (&buffer->mutex){+.+.}-{4:4}, at: configfs_write_iter+0x76/0x4c0 fs/configfs/file.c:226 #3: ffff88802836c678 (&p->frag_sem){.+.+}-{4:4}, at: flush_write_buffer fs/configfs/file.c:205 [inline] #3: ffff88802836c678 (&p->frag_sem){.+.+}-{4:4}, at: configfs_write_iter+0x218/0x4c0 fs/configfs/file.c:229 #4: ffffffff8f65ede8 (target_devices_lock){+.+.}-{4:4}, at: target_core_item_dbroot_store+0x21/0x300 drivers/target/target_core_configfs.c:114 stack backtrace: CPU: 1 UID: 0 PID: 6458 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_deadlock_bug.cold+0xbd/0xca kernel/locking/lockdep.c:3041 check_deadlock kernel/locking/lockdep.c:3093 [inline] validate_chain kernel/locking/lockdep.c:3895 [inline] __lock_acquire+0x1287/0x2690 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x17c/0x330 kernel/locking/lockdep.c:5825 down_read+0x99/0x460 kernel/locking/rwsem.c:1537 __configfs_open_file+0xe8/0x9c0 fs/configfs/file.c:304 do_dentry_open+0x73e/0x1570 fs/open.c:962 vfs_open+0x82/0x3f0 fs/open.c:1094 do_open fs/namei.c:4637 [inline] path_openat+0x21dc/0x3120 fs/namei.c:4796 do_filp_open+0x1f7/0x420 fs/namei.c:4823 file_open_name+0x198/0x3b0 fs/open.c:1376 filp_open+0x4b/0x80 fs/open.c:1396 target_core_item_dbroot_store+0x108/0x300 drivers/target/target_core_configfs.c:134 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x302/0x4c0 fs/configfs/file.c:229 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x6ac/0x1070 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3eb239a539 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:00007f3eb31fa028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f3eb2605fa0 RCX: 00007f3eb239a539 RDX: 0000000000000fff RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007f3eb242dee0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3eb2606038 R14: 00007f3eb2605fa0 R15: 00007fff2b6e3ce8 db_root: not a directory: /sys/kernel/config/target/dbroot Tested on: commit: 05f7e89a Linux 6.19 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=124dd402580000 kernel config: https://syzkaller.appspot.com/x/.config?x=55c0bf5c4b466402 dashboard link: https://syzkaller.appspot.com/bug?extid=f6e8174215573a84b797 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=149f17fa580000