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 5462228CF77 for ; Tue, 21 Apr 2026 15:34:23 +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=1776785665; cv=none; b=sJ1mShLWOqxcQvjQD2ExhqYBq1JsdMpT27kueVZgpwRZ52wGO5Yzie9jXvuZgEdIXjqrrQigEPGIrqQMWRljwcUc1Xvw4i9iFpG/N/izXjhSjP+0Yo7Fwf0xnBWx9xLAYHhPfSAuLT5HrkgDS+S5GTcujWZjsul+ptwqzxmfbbA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776785665; c=relaxed/simple; bh=eBAMUkEynxLEarOPQfCYCc3USiikWa0E2r+a91RVBuU=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=klfSRP443/5oKHvfpJRzi6C14EiG8F5gI6Uf6z6c2Q2OneHJY9igZOFII0dD/MjPxiFGMCKR45gnaeID/o15CQxY/VkxXszuFJpQY6S8N7LEYf3AsWk25+FkN+IXBPSBLd2z2J2IvJR4bjVRUdX8YOCkLI3EOo9yIgt6l+dP3Uo= 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 006d021491bc7-68e924f632bso7499978eaf.0 for ; Tue, 21 Apr 2026 08:34:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776785662; x=1777390462; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=LRuP+kKagoHrTdnYr51EPxRnKXTEHAevj5lSmoWGnQM=; b=XFofsgU2NoEQMDPnRPYUuoOJwSC2SLtluWW+cpMt3QaYK6wX/oK8s6YQPEg75fU7pg aLjtndyjCgnYcB6s3FGR4wYjiUGwvaegWvk4CQGw7ZyImPurcfDbabWG9Zfwkp/O2Vbu 2wiN7KoFrq/tmhTejmE/lrCj3kQRddVP3dOkaDHU36zcCj+n4+UPf0L2eQ34E2y0odem YWk5lIMPFMc6plDYKfogYeiEC+8ZZgAg7Dh3bTbQKuwJsuJOtec3fHSExkfQJKihR4Do BhsR8I1/qPpCe4td6p2JWV8hWv164/0Mk72XhVQmKf9EDDZzDbx8uzfbRX44P5qVRsYy VxAA== X-Forwarded-Encrypted: i=1; AFNElJ93crd/rudDdi4I4YRxZlRjDymLmaUntEACmnlCerRRRJfyKMLJhyB8D6LjEO9Rhixl/bYpJZ8s/u7kERo=@vger.kernel.org X-Gm-Message-State: AOJu0YzvURSn43MDJEwWHEL4uNzLBeRQWvoxfb4unxtOrREHCq88Cg9b Bxfb5nM5l6C7YL/vQj37Uiq7Kqr+rSK+kPnj6K2frNWDRxi1qd1eGHA4f1qKWiYzCdEy4Y2nChk oGN6AsFiyO9q5Ns8feGAxZHp5cDgPM7uwsZS3UMAu9XtCCqxch7lX19EU9b4= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:174b:b0:694:8f3a:3f31 with SMTP id 006d021491bc7-6948f3a4350mr3429084eaf.26.1776785662338; Tue, 21 Apr 2026 08:34:22 -0700 (PDT) Date: Tue, 21 Apr 2026 08:34:22 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69e798fe.050a0220.24bfd3.0032.GAE@google.com> Subject: [syzbot] [mm?] possible deadlock in rhashtable_free_and_destroy From: syzbot To: akpm@linux-foundation.org, axelrasmussen@google.com, david@kernel.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, mhocko@kernel.org, shakeel.butt@linux.dev, syzkaller-bugs@googlegroups.com, weixugc@google.com, yuanchu@google.com, zhengqi.arch@bytedance.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 8541d8f725c6 Merge tag 'mtd/for-7.1' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15380836580000 kernel config: https://syzkaller.appspot.com/x/.config?x=7e54da1916e8d11f dashboard link: https://syzkaller.appspot.com/bug?extid=5af806780f38a5fe691f 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-8541d8f7.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/22dfea2c37c2/vmlinux-8541d8f7.xz kernel image: https://storage.googleapis.com/syzbot-assets/e2f93ad68fe3/bzImage-8541d8f7.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5af806780f38a5fe691f@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ kswapd0/108 is trying to acquire lock: ffff888056f3c4e8 (&ht->mutex){+.+.}-{4:4}, at: rhashtable_free_and_destroy+0x3d/0x9b0 lib/rhashtable.c:1154 but task is already holding lock: ffffffff8e9b0800 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0xb5d/0x1ac0 mm/vmscan.c:7102 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:4327 [inline] fs_reclaim_acquire+0xc4/0x100 mm/page_alloc.c:4341 might_alloc include/linux/sched/mm.h:317 [inline] slab_pre_alloc_hook mm/slub.c:4520 [inline] slab_alloc_node mm/slub.c:4875 [inline] __do_kmalloc_node mm/slub.c:5294 [inline] __kvmalloc_node_noprof+0xcc/0xa00 mm/slub.c:6828 bucket_table_alloc.isra.0+0x88/0x460 lib/rhashtable.c:186 rhashtable_rehash_alloc+0x68/0x110 lib/rhashtable.c:368 rht_deferred_worker+0x1d9/0x1fd0 lib/rhashtable.c:429 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 (&ht->mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 rhashtable_free_and_destroy+0x3d/0x9b0 lib/rhashtable.c:1154 shmem_evict_inode+0x1ae/0xc40 mm/shmem.c:1429 evict+0x3c2/0xad0 fs/inode.c:841 iput_final fs/inode.c:1960 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2009 iput+0x35/0x40 fs/inode.c:1975 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 finish_dput+0x76/0x480 fs/dcache.c:879 dput.part.0+0x456/0x570 fs/dcache.c:928 dput+0x1f/0x30 fs/dcache.c:920 ovl_destroy_inode+0x3e/0x190 fs/overlayfs/super.c:217 destroy_inode+0xcb/0x1c0 fs/inode.c:394 evict+0x599/0xad0 fs/inode.c:865 iput_final fs/inode.c:1960 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2009 iput+0x35/0x40 fs/inode.c:1975 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+0x416/0x1240 mm/shrinker.c:440 shrink_slab_memcg mm/shrinker.c:557 [inline] shrink_slab+0xa7d/0x12e0 mm/shrinker.c:635 shrink_one+0x398/0x7f0 mm/vmscan.c:4932 shrink_many mm/vmscan.c:4993 [inline] lru_gen_shrink_node mm/vmscan.c:5071 [inline] shrink_node+0x2673/0x3dc0 mm/vmscan.c:6059 kswapd_shrink_node mm/vmscan.c:6913 [inline] balance_pgdat+0xaaf/0x1ac0 mm/vmscan.c:7089 kswapd+0x557/0xb60 mm/vmscan.c:7362 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&ht->mutex); lock(fs_reclaim); lock(&ht->mutex); *** DEADLOCK *** 2 locks held by kswapd0/108: #0: ffffffff8e9b0800 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0xb5d/0x1ac0 mm/vmscan.c:7102 #1: ffff88801347c0d8 (&type->s_umount_key#76){++++}-{4:4}, at: super_trylock_shared fs/super.c:565 [inline] #1: ffff88801347c0d8 (&type->s_umount_key#76){++++}-{4:4}, at: super_cache_scan+0x98/0x550 fs/super.c:198 stack backtrace: CPU: 2 UID: 0 PID: 108 Comm: kswapd0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP 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_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x14b8/0x2630 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:632 [inline] __mutex_lock+0x1a4/0x1b10 kernel/locking/mutex.c:806 rhashtable_free_and_destroy+0x3d/0x9b0 lib/rhashtable.c:1154 shmem_evict_inode+0x1ae/0xc40 mm/shmem.c:1429 evict+0x3c2/0xad0 fs/inode.c:841 iput_final fs/inode.c:1960 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2009 iput+0x35/0x40 fs/inode.c:1975 dentry_unlink_inode+0x2a1/0x490 fs/dcache.c:467 __dentry_kill+0x1d0/0x600 fs/dcache.c:670 finish_dput+0x76/0x480 fs/dcache.c:879 dput.part.0+0x456/0x570 fs/dcache.c:928 dput+0x1f/0x30 fs/dcache.c:920 ovl_destroy_inode+0x3e/0x190 fs/overlayfs/super.c:217 destroy_inode+0xcb/0x1c0 fs/inode.c:394 evict+0x599/0xad0 fs/inode.c:865 iput_final fs/inode.c:1960 [inline] iput.part.0+0x605/0xf50 fs/inode.c:2009 iput+0x35/0x40 fs/inode.c:1975 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+0x416/0x1240 mm/shrinker.c:440 shrink_slab_memcg mm/shrinker.c:557 [inline] shrink_slab+0xa7d/0x12e0 mm/shrinker.c:635 shrink_one+0x398/0x7f0 mm/vmscan.c:4932 shrink_many mm/vmscan.c:4993 [inline] lru_gen_shrink_node mm/vmscan.c:5071 [inline] shrink_node+0x2673/0x3dc0 mm/vmscan.c:6059 kswapd_shrink_node mm/vmscan.c:6913 [inline] balance_pgdat+0xaaf/0x1ac0 mm/vmscan.c:7089 kswapd+0x557/0xb60 mm/vmscan.c:7362 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- 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