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Tue, 10 Feb 2026 07:42:17 -0800 (PST) Date: Tue, 10 Feb 2026 07:42:17 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <698b51d9.050a0220.340abe.0005.GAE@google.com> Subject: [moderation/CI] Re: Virtual Swap Space From: syzbot ci To: syzkaller-upstream-moderation@googlegroups.com Cc: syzbot@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 infrastr= ucture * [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 implementa= tion * [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 d= escriptor * [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 la= yer * [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 physic= al 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~exp= 1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/f444cfbe-4ce0-4917-94aa-3a8bd96ee37= 6/config C repro: https://ci.syzbot.org/findings/7b8c50b1-47d6-42e0-bcfc-814e7b3bb= 596/c_repro syz repro: https://ci.syzbot.org/findings/7b8c50b1-47d6-42e0-bcfc-814e7b3bb= 596/syz_repro loop0: detected capacity change from 0 to 764 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 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/li= nux/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 incl= ude/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 inclu= de/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 inc= lude/linux/rcupdate.h:331 [inline] #2: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock includ= e/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. The email will later be sent to: [akpm@linux-foundation.org axelrasmussen@google.com baohua@kernel.org bhe@r= edhat.com cgroups@vger.kernel.org chengming.zhou@linux.dev chrisl@kernel.or= g christophe.leroy@csgroup.eu gourry@gourry.net hannes@cmpxchg.org huang.yi= ng.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-kerne= l@vger.kernel.org linux-mm@kvack.org linux-pm@vger.kernel.org lorenzo.stoak= es@oracle.com mhocko@kernel.org muchun.song@linux.dev npache@redhat.com nph= amcs@gmail.com osalvador@suse.de pavel@kernel.org peterx@redhat.com pfalcat= o@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 z= hengqi.arch@bytedance.com] If the report looks fine to you, reply with: #syz upstream If the report is a false positive, reply with #syz invalid