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AKwUvByjPVnC9BZNbqaqYXh/AykF5+0p6SIDrZpD0dBCBCGcIcgonykdKcrQvxFI6uTvfVA1C8phjvUoHP72Iyk=@vger.kernel.org X-Gm-Message-State: AFuF++ld98rvqP80EsmrDTddJaTen5/mY6ngYOkco0jEm7+AhJ3ly4qh NO5UQ7SrRuB36IEteF15TDhU9GywIIm2qlbDIBiGrFtk8Ay9KcIyhYWB7XAVCPFlBV75SQK+TZ+ PqmnFGWKqfTdfBxFQytuUJP16orQ8+9NVue0yH/LYcm7tYQ3Hbm2qPbPCBr0= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2084:b0:6c2:6f93:389f with SMTP id 006d021491bc7-6ca9bd48180mr11162028eaf.37.1789998136361; Mon, 21 Sep 2026 06:42:16 -0700 (PDT) Date: Mon, 21 Sep 2026 06:42:16 -0700 In-Reply-To: <20260918180241.3424851-1-nphamcs@gmail.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6ab13438.71f81b7d.15fa6d.002c.GAE@google.com> Subject: [syzbot ci] Re: Virtual Swap Space (Swap Table Edition) From: syzbot ci To: akpm@linux-foundation.org, axelrasmussen@google.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, baoquan.he@linux.dev, cgroups@vger.kernel.org, chengming.zhou@linux.dev, chrisl@kernel.org, corbet@lwn.net, david@kernel.org, gourry@gourry.net, hannes@cmpxchg.org, haowenchao22@gmail.com, hughd@google.com, kasong@tencent.com, kernel-team@meta.com, kunwu.chan@linux.dev, liam@infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, mhocko@kernel.org, mkoutny@suse.com, muchun.song@linux.dev, nphamcs@gmail.com, qi.zheng@linux.dev, riel@surriel.com, roman.gushchin@linux.dev, rppt@kernel.org, shakeel.butt@linux.dev, shikemeng@huaweicloud.com, skhan@linuxfoundation.org, surenb@google.com, tj@kernel.org, vbabka@kernel.org, weixugc@google.com, yosry@kernel.org, youngjun.park@lge.com, yuanchu@google.com Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v5] Virtual Swap Space (Swap Table Edition) https://lore.kernel.org/all/20260918180241.3424851-1-nphamcs@gmail.com * [PATCH v5 01/11] mm, swap: add virtual swap device infrastructure * [PATCH v5 02/11] mm, swap: support zswap and zero-filled swap pages as vswap backends * [PATCH v5 03/11] mm, swap: prepare the swap IO path for vswap * [PATCH v5 04/11] mm, swap: support physical swap as a vswap backend * [PATCH v5 05/11] mm, swap: enable THP swapin for vswap entries * [PATCH v5 06/11] mm, swap: write back vswap zswap entries to physical swap * [PATCH v5 07/11] mm, swap: reclaim physical slots backing cache-only vswap entries * [PATCH v5 08/11] mm, swap: only charge physical swap entries * [PATCH v5 09/11] mm, swap: add debugfs counters for vswap * [PATCH v5 10/11] mm, swap: defer memcg_table allocation for physical swap clusters * [RFC PATCH v5 11/11] mm, swap: back vswap clusters with a VM_SPARSE array and found the following issue: KASAN: null-ptr-deref Read in swap_entry_backend_has_flag Full report is available here: https://ci.syzbot.org/series/713f2473-328a-4c16-8bce-63005d15a338 *** KASAN: null-ptr-deref Read in swap_entry_backend_has_flag tree: linux-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next base: 27e4e1835109ef599d72abe6c09711e0b1916033 arch: amd64 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 config: https://ci.syzbot.org/builds/26b06329-3b1c-4c73-8ee3-64c53b995186/config syz repro: https://ci.syzbot.org/findings/f743742b-1934-4b4e-a590-9a36592da902/syz_repro ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:82 [inline] BUG: KASAN: null-ptr-deref in atomic_long_read include/linux/atomic/atomic-instrumented.h:3188 [inline] BUG: KASAN: null-ptr-deref in __vtable_get mm/vswap.h:163 [inline] BUG: KASAN: null-ptr-deref in vswap_to_phys mm/vswap.h:202 [inline] BUG: KASAN: null-ptr-deref in swap_entry_backend_has_flag+0xea/0x210 mm/vswap.h:409 Read of size 8 at addr 0000000000000e00 by task syz.1.38/5916 CPU: 1 UID: 0 PID: 5916 Comm: syz.1.38 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 kasan_report+0x117/0x150 mm/kasan/report.c:595 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200 instrument_atomic_read include/linux/instrumented.h:82 [inline] atomic_long_read include/linux/atomic/atomic-instrumented.h:3188 [inline] __vtable_get mm/vswap.h:163 [inline] vswap_to_phys mm/vswap.h:202 [inline] swap_entry_backend_has_flag+0xea/0x210 mm/vswap.h:409 do_swap_page+0x767/0x5a20 mm/memory.c:5042 __collapse_huge_page_swapin mm/khugepaged.c:1152 [inline] collapse_huge_page mm/khugepaged.c:1271 [inline] mthp_collapse mm/khugepaged.c:1469 [inline] collapse_run_pmd+0xaf1/0x5d90 mm/khugepaged.c:2811 madvise_collapse mm/madvise.c:1026 [inline] madvise_vma_behavior+0x17cf/0x4d80 mm/madvise.c:1548 madvise_walk_vmas+0x576/0xb00 mm/madvise.c:1896 madvise_do_behavior+0x385/0x540 mm/madvise.c:2091 do_madvise+0x26f/0x330 mm/madvise.c:2189 __do_sys_madvise mm/madvise.c:2198 [inline] __se_sys_madvise mm/madvise.c:2196 [inline] __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2196 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7b5939e159 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:00007f7b5a1ff028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f7b59625fa0 RCX: 00007f7b5939e159 RDX: 0000000000000019 RSI: 0000000000c00000 RDI: 0000200000000000 RBP: 00007f7b5943506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7b59626038 R14: 00007f7b59625fa0 R15: 00007ffe5f2d8d38 ================================================================== *** 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. To test a fix for this bug, please reply with `#syz test` (on a separate line) and attach the patch to the email. Notes: - The patch will be applied on top of the tested series (as an incremental fix). - To test a new version of the whole series, please send it directly to syzbot@lists.linux.dev. - Arguments like custom git repos and branches are not supported.