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AHgh+RqJGcA+WsG98Am/HZg1jNVn2WrTG9WaF22ClKh1uGL5j4UagTSIBmXRRDP3a09DMkTQD9WulHtS@vger.kernel.org X-Gm-Message-State: AOJu0YxlYZxRPySBsNlOSx9x+PgFLubhPGZil1VzeoOlW1iAbfDXH/aw AWD9Aq6DGtRYgP1NETHqC+56/HwbKWZm6xyMS9MhjyINiqID+vWv6pfC3tNX0tDlYftB+w/vlm6 Uc5cbBoj+GyI9zJ87246DhTZKSzrEBvdOE/Ib3NkEUqcgL9RIPyUeyK22PPI= Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:169f:b0:485:7c46:b866 with SMTP id 5614622812f47-4afc513e9b0mr6403807b6e.16.1786080369495; Thu, 06 Aug 2026 22:26:09 -0700 (PDT) Date: Thu, 06 Aug 2026 22:26:09 -0700 In-Reply-To: <20260806184254.3790858-1-nphamcs@gmail.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a756c71.01d0871a.3a0d52.003a.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, 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, kasong@tencent.com, kernel-team@meta.com, liam@infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, mhocko@kernel.org, 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, surenb@google.com, 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 [v3] Virtual Swap Space (Swap Table Edition) https://lore.kernel.org/all/20260806184254.3790858-1-nphamcs@gmail.com * [PATCH v3 01/11] mm, swap: add virtual swap device infrastructure * [PATCH v3 02/11] mm, swap: support zswap and zeroswap as vswap backends * [PATCH v3 03/11] mm, swap: prepare the swap IO path for vswap * [PATCH v3 04/11] mm, swap: support physical swap as a vswap backend * [PATCH v3 05/11] mm, swap: enable THP swapin for vswap entries * [PATCH v3 06/11] mm, swap: write back vswap zswap entries to physical swap * [PATCH v3 07/11] mm, swap: reclaim physical slots backing cache-only vswap entries * [PATCH v3 08/11] mm, swap: only charge physical swap entries * [PATCH v3 09/11] mm, swap: add debugfs counters for vswap * [PATCH v3 10/11] mm, swap: defer memcg_table allocation for physical swap clusters * [PATCH v3 11/11] mm, swap: widen swap_info_struct max/pages to unsigned long 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/e7da1097-3230-4e50-80cb-1dfafeebea40 *** 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: bacc32cc7de65ffff70080a48eb294f89e434d5e 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/4f943657-9481-4637-9b1f-9be1bff18f92/config syz repro: https://ci.syzbot.org/findings/f6c4f1ab-951c-4759-b397-e22c23c3bf32/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:147 [inline] BUG: KASAN: null-ptr-deref in vswap_to_phys mm/vswap.h:197 [inline] BUG: KASAN: null-ptr-deref in swap_entry_backend_has_flag+0xfe/0x220 mm/vswap.h:441 Read of size 8 at addr 0000000000000000 by task syz.2.20/5818 CPU: 1 UID: 0 PID: 5818 Comm: syz.2.20 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:147 [inline] vswap_to_phys mm/vswap.h:197 [inline] swap_entry_backend_has_flag+0xfe/0x220 mm/vswap.h:441 do_swap_page+0x3c0/0x5620 mm/memory.c:4975 __collapse_huge_page_swapin mm/khugepaged.c:1202 [inline] collapse_huge_page mm/khugepaged.c:1325 [inline] mthp_collapse mm/khugepaged.c:1524 [inline] collapse_scan_pmd mm/khugepaged.c:1786 [inline] collapse_single_pmd+0x24c6/0x3da0 mm/khugepaged.c:2803 madvise_collapse+0x2cf/0x790 mm/khugepaged.c:3237 madvise_vma_behavior+0x115f/0x4170 mm/madvise.c:1363 madvise_walk_vmas+0x576/0xb00 mm/madvise.c:1712 madvise_do_behavior+0x385/0x540 mm/madvise.c:1907 do_madvise+0x327/0x3a0 mm/madvise.c:2005 __do_sys_madvise mm/madvise.c:2014 [inline] __se_sys_madvise mm/madvise.c:2012 [inline] __x64_sys_madvise+0xa6/0xc0 mm/madvise.c:2012 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbcad79e019 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:00007fbcae5c4028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007fbcada25fa0 RCX: 00007fbcad79e019 RDX: 0000000000000019 RSI: 0000000000c00000 RDI: 0000200000000000 RBP: 00007fbcad83500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbcada26038 R14: 00007fbcada25fa0 R15: 00007fff095fa0b8 ================================================================== *** 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 patch for this bug, please reply with `#syz test` (should be on a separate line). The patch should be attached to the email. Note: arguments like custom git repos and branches are not supported.