From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f80.google.com (mail-oo1-f80.google.com [209.85.161.80]) (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 ABA7D2F3614 for ; Fri, 10 Apr 2026 20:27:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775852846; cv=none; b=ucP0llHRqS3Adk9bHm5xmIyzhE3RvCoR+DrhptM7PTLzXq2P4JK32MCNexCtV2YkSE0gtxcIsER4eNiQTRNbU3gR6dhRpuK47tyaZeaZP0V2uvRQsQ/8PapLc36IJt6LC603rbk5e8cbYSAn6rjsB7KZZ0f626e7X9HbgcMpdn0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775852846; c=relaxed/simple; bh=V4lN9NmG5Pidm5BUOOPIERyDM0BYGPSoAFHypKp4BEM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=RLJ1QgAe1m7YtsvDQMPfnszmjhXCAZH3dqBe1uDtW4qYOi7Mf6mrdrXl7gvgM/gka8MMRmkes18BxOMHrU/qDZWvtLx4+krxhSzmYfa0Otf4tKkX4/SWg/R/9FedmJzeBtC+HMGXhx9HmZ3Y95+TCpuP00SVhzND3GLn7yN5LNQ= 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=209.85.161.80 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-f80.google.com with SMTP id 006d021491bc7-6888581ca85so2323369eaf.2 for ; Fri, 10 Apr 2026 13:27:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775852844; x=1776457644; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=TXpWDB8nNV2yhSw++8KxIhIDrUI7imNBORjrmfUqvr4=; b=HhWbHcOi5ZrCLgugu0V2zl/mkohPL2s7dFdgPA9joZzTFYEL5tOQQDzd2UPULfg2RY Vkjt1/Fgi5GLmF5YWCRibUuQ8ahV4J7BGzxVXr9IRUghrmS6i0OYKc19EYkt3q2MBDI9 nOb2Nii2Qc1L0YUMPIwQyMBxOKjQ6aaRA+DvRDLawv+DEAdXUqTcZVMOdtrzuTpMzYmq ZM1SajYpov0wj20CowVaaX+lZ6/viCfxoohVCPHWrZx8GuJShhSjP8cjixTENaFryyQT OHPioD/esMy7ELM9sOZSteKiLoUUo//PxBSdBbGjtBzgqBA/fUL8zaDK/bOEVcLyxHGs 2vJQ== X-Forwarded-Encrypted: i=1; AJvYcCXBcZ2UE/Y+OrHtfxtuXMuRH99buOeOppZiNPEFe6DbnNF2fn/Y2ZvNqQ+6G3CUjml0Lp1f3uINxr+0qMA=@vger.kernel.org X-Gm-Message-State: AOJu0Ywdd+3N55RQOhWJVBCBBGgYmB/u62YUdqij1sLd4EAi/LwhdGuK AlQRT/UPPaXLYx03dBJHPs3Txl9XN/nBuG7oslCBc33u8loHnPk/2sq6mp6EeZ4bqeZ3v+ijhhx bpwM3cXvcTQHC3JOAI97o9+P1cakxj33rGbW14WVCZB+YESjiVCEUKYJ47Gw= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2d04:b0:68c:1689:6967 with SMTP id 006d021491bc7-68c16896d02mr2031328eaf.44.1775852843739; Fri, 10 Apr 2026 13:27:23 -0700 (PDT) Date: Fri, 10 Apr 2026 13:27:23 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69d95d2b.050a0220.3030df.0031.GAE@google.com> Subject: [syzbot] [kernfs?] WARNING: suspicious RCU usage in kernfs_put From: syzbot To: driver-core@lists.linux.dev, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tj@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 591cd656a1bf Linux 7.0-rc7 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1439a302580000 kernel config: https://syzkaller.appspot.com/x/.config?x=64e78d99d9bf8b4c dashboard link: https://syzkaller.appspot.com/bug?extid=0dfe499ea713e0a15bec 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: https://storage.googleapis.com/syzbot-assets/bf0f027c93ec/disk-591cd656.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/60d829be17f4/vmlinux-591cd656.xz kernel image: https://storage.googleapis.com/syzbot-assets/673c009c7550/bzImage-591cd656.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0dfe499ea713e0a15bec@syzkaller.appspotmail.com ============================= WARNING: suspicious RCU usage syzkaller #0 Tainted: G L ----------------------------- fs/kernfs/dir.c:579 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by kswapd0/78: #0: ffffffff8e9aa8a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x1db/0x1ca0 mm/vmscan.c:6968 #1: ffff888033c040e0 (&type->s_umount_key#57){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:565 [inline] #1: ffff888033c040e0 (&type->s_umount_key#57){.+.+}-{4:4}, at: super_cache_scan+0x98/0x550 fs/super.c:198 stack backtrace: CPU: 0 UID: 0 PID: 78 Comm: kswapd0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 lockdep_rcu_suspicious.cold+0x4f/0xb1 kernel/locking/lockdep.c:6876 kernfs_put.part.0+0x59c/0x610 fs/kernfs/dir.c:579 kernfs_put+0x53/0x60 fs/kernfs/dir.c:602 evict+0x3c2/0xad0 fs/inode.c:846 iput_final fs/inode.c:1966 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 shrink_kill fs/dcache.c:1147 [inline] shrink_dentry_list+0x180/0x5e0 fs/dcache.c:1174 prune_dcache_sb+0xea/0x150 fs/dcache.c:1256 super_cache_scan+0x328/0x550 fs/super.c:223 do_shrink_slab+0x416/0x11e0 mm/shrinker.c:437 shrink_slab+0x171/0x12b0 mm/shrinker.c:664 shrink_one+0x398/0x7f0 mm/vmscan.c:4928 shrink_many mm/vmscan.c:4989 [inline] lru_gen_shrink_node mm/vmscan.c:5067 [inline] shrink_node+0x26a2/0x3e20 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6894 [inline] balance_pgdat+0xbb7/0x1ca0 mm/vmscan.c:7070 kswapd+0x556/0xba0 mm/vmscan.c:7343 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ============================= WARNING: suspicious RCU usage syzkaller #0 Tainted: G L ----------------------------- fs/kernfs/dir.c:579 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by kswapd0/78: #0: ffffffff8e9aa8a0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x1db/0x1ca0 mm/vmscan.c:6968 #1: ffff888033c040e0 (&type->s_umount_key#57){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:565 [inline] #1: ffff888033c040e0 (&type->s_umount_key#57){.+.+}-{4:4}, at: super_cache_scan+0x98/0x550 fs/super.c:198 stack backtrace: CPU: 0 UID: 0 PID: 78 Comm: kswapd0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 lockdep_rcu_suspicious.cold+0x4f/0xb1 kernel/locking/lockdep.c:6876 kernfs_put.part.0+0x515/0x610 fs/kernfs/dir.c:579 kernfs_put+0x53/0x60 fs/kernfs/dir.c:602 evict+0x3c2/0xad0 fs/inode.c:846 iput_final fs/inode.c:1966 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 shrink_kill fs/dcache.c:1147 [inline] shrink_dentry_list+0x180/0x5e0 fs/dcache.c:1174 prune_dcache_sb+0xea/0x150 fs/dcache.c:1256 super_cache_scan+0x328/0x550 fs/super.c:223 do_shrink_slab+0x416/0x11e0 mm/shrinker.c:437 shrink_slab+0x171/0x12b0 mm/shrinker.c:664 shrink_one+0x398/0x7f0 mm/vmscan.c:4928 shrink_many mm/vmscan.c:4989 [inline] lru_gen_shrink_node mm/vmscan.c:5067 [inline] shrink_node+0x26a2/0x3e20 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6894 [inline] balance_pgdat+0xbb7/0x1ca0 mm/vmscan.c:7070 kswapd+0x556/0xba0 mm/vmscan.c:7343 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ------------[ cut here ]------------ kernfs_put: tty/ptyd1: released with incorrect active_ref 0 WARNING: fs/kernfs/dir.c:579 at kernfs_put.part.0+0x478/0x610 fs/kernfs/dir.c:579, CPU#0: kswapd0/78 Modules linked in: CPU: 0 UID: 0 PID: 78 Comm: kswapd0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:kernfs_put.part.0+0x483/0x610 fs/kernfs/dir.c:579 Code: 89 c6 89 44 24 1c e8 5c 2d 51 ff 8b 44 24 1c 85 c0 75 21 e8 9f 32 51 ff 48 8d 3d 88 21 29 0e 48 8b 54 24 10 44 89 f9 4c 89 e6 <67> 48 0f b9 3a e9 3a fc ff ff e8 7e 32 51 ff e8 d9 f0 34 ff 31 ff RSP: 0018:ffffc9000236f2d8 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888023738000 RCX: 0000000000000000 RDX: ffff888022f9cea0 RSI: ffffffff8c2cde20 RDI: ffffffff90e03230 RBP: ffff88801facbc30 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff8c2cde20 R13: dffffc0000000000 R14: ffff88801c6b5868 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888124340000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055923cfd5ee8 CR3: 000000000e598000 CR4: 00000000003526f0 Call Trace: kernfs_put+0x53/0x60 fs/kernfs/dir.c:602 evict+0x3c2/0xad0 fs/inode.c:846 iput_final fs/inode.c:1966 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2015 iput+0x35/0x40 fs/inode.c:1981 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 shrink_kill fs/dcache.c:1147 [inline] shrink_dentry_list+0x180/0x5e0 fs/dcache.c:1174 prune_dcache_sb+0xea/0x150 fs/dcache.c:1256 super_cache_scan+0x328/0x550 fs/super.c:223 do_shrink_slab+0x416/0x11e0 mm/shrinker.c:437 shrink_slab+0x171/0x12b0 mm/shrinker.c:664 shrink_one+0x398/0x7f0 mm/vmscan.c:4928 shrink_many mm/vmscan.c:4989 [inline] lru_gen_shrink_node mm/vmscan.c:5067 [inline] shrink_node+0x26a2/0x3e20 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6894 [inline] balance_pgdat+0xbb7/0x1ca0 mm/vmscan.c:7070 kswapd+0x556/0xba0 mm/vmscan.c:7343 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 89 c6 mov %eax,%esi 2: 89 44 24 1c mov %eax,0x1c(%rsp) 6: e8 5c 2d 51 ff call 0xff512d67 b: 8b 44 24 1c mov 0x1c(%rsp),%eax f: 85 c0 test %eax,%eax 11: 75 21 jne 0x34 13: e8 9f 32 51 ff call 0xff5132b7 18: 48 8d 3d 88 21 29 0e lea 0xe292188(%rip),%rdi # 0xe2921a7 1f: 48 8b 54 24 10 mov 0x10(%rsp),%rdx 24: 44 89 f9 mov %r15d,%ecx 27: 4c 89 e6 mov %r12,%rsi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: e9 3a fc ff ff jmp 0xfffffc6e 34: e8 7e 32 51 ff call 0xff5132b7 39: e8 d9 f0 34 ff call 0xff34f117 3e: 31 ff xor %edi,%edi --- This report is generated by a bot. 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