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AJvYcCWEzM8qyhtkgElyXxaR0r+smQIVoBoyFddVH66cZpBikvgWjNqhpGHXi0ViadJWpClSjDaWEmXa@vger.kernel.org X-Gm-Message-State: AOJu0YzBKGK1W4BfNykAF/DbVhZdhgMXZoETzJMgGP6Nj6F5NhQQUAJf Lbq0iHcydVb0fQ/f1QfHgL6ggev/xQZi7rlVukI3v4nxSyu1SGSnOu6qNph/Fb1XuLwBS8lQfb+ IQVHx81QfejT1ZcAsmgubm+6Kp/G1RpAlQ8HEDut42eYFZD/ZduvyUIVGBs4= Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:818b:b0:66d:ecba:b3f4 with SMTP id 006d021491bc7-672e62cc5a8mr1455324eaf.31.1770738348353; Tue, 10 Feb 2026 07:45:48 -0800 (PST) Date: Tue, 10 Feb 2026 07:45:48 -0800 In-Reply-To: <20260208215839.87595-1-nphamcs@gmail.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <698b52ac.a70a0220.2c38d7.0076.GAE@google.com> Subject: [syzbot ci] Re: Virtual Swap Space From: syzbot ci To: akpm@linux-foundation.org, axelrasmussen@google.com, baohua@kernel.org, bhe@redhat.com, cgroups@vger.kernel.org, chengming.zhou@linux.dev, chrisl@kernel.org, christophe.leroy@csgroup.eu, gourry@gourry.net, hannes@cmpxchg.org, huang.ying.caritas@gmail.com, hughd@google.com, jannh@google.com, joshua.hahnjy@gmail.com, kasong@tencent.com, kernel-team@meta.com, len.brown@intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, lorenzo.stoakes@oracle.com, mhocko@kernel.org, muchun.song@linux.dev, npache@redhat.com, nphamcs@gmail.com, osalvador@suse.de, pavel@kernel.org, peterx@redhat.com, pfalcato@suse.de, rafael@kernel.org, riel@surriel.com, roman.gushchin@linux.dev, ryan.roberts@arm.com, shakeel.butt@linux.dev, shikemeng@huaweicloud.com, viro@zeniv.linux.org.uk, weixugc@google.com, yosry.ahmed@linux.dev, yuanchu@google.com, zhengqi.arch@bytedance.com Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v3] Virtual Swap Space https://lore.kernel.org/all/20260208215839.87595-1-nphamcs@gmail.com * [PATCH v3 01/20] mm/swap: decouple swap cache from physical swap infrastructure * [PATCH v3 02/20] swap: rearrange the swap header file * [PATCH v3 03/20] mm: swap: add an abstract API for locking out swapoff * [PATCH v3 04/20] zswap: add new helpers for zswap entry operations * [PATCH v3 05/20] mm/swap: add a new function to check if a swap entry is in swap cached. * [PATCH v3 06/20] mm: swap: add a separate type for physical swap slots * [PATCH v3 07/20] mm: create scaffolds for the new virtual swap implementation * [PATCH v3 08/20] zswap: prepare zswap for swap virtualization * [PATCH v3 09/20] mm: swap: allocate a virtual swap slot for each swapped out page * [PATCH v3 10/20] swap: move swap cache to virtual swap descriptor * [PATCH v3 11/20] zswap: move zswap entry management to the virtual swap descriptor * [PATCH v3 12/20] swap: implement the swap_cgroup API using virtual swap * [PATCH v3 13/20] swap: manage swap entry lifecycle at the virtual swap layer * [PATCH v3 14/20] mm: swap: decouple virtual swap slot from backing store * [PATCH v3 15/20] zswap: do not start zswap shrinker if there is no physical swap slots * [PATCH v3 16/20] swap: do not unnecesarily pin readahead swap entries * [PATCH v3 17/20] swapfile: remove zeromap bitmap * [PATCH v3 18/20] memcg: swap: only charge physical swap slots * [PATCH v3 19/20] swap: simplify swapoff using virtual swap * [PATCH v3 20/20] swapfile: replace the swap map with bitmaps and found the following issue: possible deadlock in vswap_iter Full report is available here: https://ci.syzbot.org/series/b9defda6-daec-4c41-bbf9-7d3b7fabd7cb *** possible deadlock in vswap_iter tree: bpf URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf.git base: 05f7e89ab9731565d8a62e3b5d1ec206485eeb0b arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/f444cfbe-4ce0-4917-94aa-3a8bd96ee376/config C repro: https://ci.syzbot.org/findings/7b8c50b1-47d6-42e0-bcfc-814e7b3bb596/c_repro syz repro: https://ci.syzbot.org/findings/7b8c50b1-47d6-42e0-bcfc-814e7b3bb596/syz_repro loop0: detected capacity change from 0 to 764 ============================================ WARNING: possible recursive locking detected syzkaller #0 Not tainted -------------------------------------------- syz-executor625/5806 is trying to acquire lock: ffff88811884c018 (&cluster->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88811884c018 (&cluster->lock){+.+.}-{3:3}, at: vswap_iter+0xfa/0x1b0 mm/vswap.c:274 but task is already holding lock: ffff88811884c018 (&cluster->lock){+.+.}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] ffff88811884c018 (&cluster->lock){+.+.}-{3:3}, at: swap_cache_lock_irq+0xe2/0x190 mm/vswap.c:1586 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&cluster->lock); lock(&cluster->lock); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by syz-executor625/5806: #0: ffff888174bc2800 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:391 [inline] #0: ffff888174bc2800 (&mm->mmap_lock){++++}-{4:4}, at: madvise_lock+0x152/0x2e0 mm/madvise.c:1789 #1: ffff88811884c018 (&cluster->lock){+.+.}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:376 [inline] #1: ffff88811884c018 (&cluster->lock){+.+.}-{3:3}, at: swap_cache_lock_irq+0xe2/0x190 mm/vswap.c:1586 #2: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #2: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #2: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: vswap_cgroup_record+0x40/0x290 mm/vswap.c:1925 stack backtrace: *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com.