From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f200.google.com (mail-oi1-f200.google.com [209.85.167.200]) (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 8B9ED3C3438 for ; Fri, 16 Oct 2026 22:07:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792188445; cv=none; b=IHwy2m/iq9CRT1zAdwKanHliO2CX7Gzv9Y967NSqBf+QMPw+JVokmPG5hcyJeYd8/ncBXcRh2sIpUkDExH9lpDGnO7ylI3S3tBbDaiAfs2VhqllMcryzAzZamzyK8PolSoRLXYu0DBepwHA5W2emN/CUeU43JZQ9s9Da2nzJ758= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792188445; c=relaxed/simple; bh=jP9GlLnCfTYsTc0ZkWUQwN3VvlU1JTrOkIKH6mpiI5o=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; 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2002:a05:6808:444b:b0:4f5:eaac:517a with SMTP id 5614622812f47-53cc22e2983mr832664b6e.1.1792188442403; Fri, 16 Oct 2026 15:07:22 -0700 (PDT) Date: Fri, 16 Oct 2026 15:07:22 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6ad2a01a.6814cce4.34c49f.0013.GAE@google.com> Subject: [syzbot] [fs?] KASAN: slab-use-after-free Write in config_item_put From: syzbot To: a.hindborg@kernel.org, leitao@debian.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 2f2f7eeef8b0 Merge tag 'soc-fixes-7.3-3' of git://git.kern.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=12d4a69c580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b38d39c45202f4fa dashboard link: https://syzkaller.appspot.com/bug?extid=63336d70e1af377d7388 compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15490031580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11d4a69c580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/f3699c762a33/disk-2f2f7eee.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/911702ec7630/vmlinux-2f2f7eee.xz kernel image: https://storage.googleapis.com/syzbot-assets/3e76f95f5acb/bzImage-2f2f7eee.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+63336d70e1af377d7388@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline] BUG: KASAN: slab-use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline] BUG: KASAN: slab-use-after-free in __refcount_sub_and_test include/linux/refcount.h:389 [inline] BUG: KASAN: slab-use-after-free in __refcount_dec_and_test include/linux/refcount.h:432 [inline] BUG: KASAN: slab-use-after-free in refcount_dec_and_test include/linux/refcount.h:450 [inline] BUG: KASAN: slab-use-after-free in kref_put include/linux/kref.h:64 [inline] BUG: KASAN: slab-use-after-free in config_item_put+0x26/0x90 fs/configfs/item.c:149 Write of size 4 at addr ffff88803b6444b4 by task syz-executor324/5709 CPU: 1 UID: 0 PID: 5709 Comm: syz-executor324 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 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_write include/linux/instrumented.h:112 [inline] atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline] __refcount_sub_and_test include/linux/refcount.h:389 [inline] __refcount_dec_and_test include/linux/refcount.h:432 [inline] refcount_dec_and_test include/linux/refcount.h:450 [inline] kref_put include/linux/kref.h:64 [inline] config_item_put+0x26/0x90 fs/configfs/item.c:149 configfs_symlink+0x6be/0x11d0 fs/configfs/symlink.c:225 vfs_symlink+0x18b/0x330 fs/namei.c:5823 filename_symlinkat+0x1cd/0x420 fs/namei.c:5848 __do_sys_symlinkat fs/namei.c:5868 [inline] __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5863 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: 0033:0x7f08b938f639 Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff52171fa8 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00312f7374726f70 RCX: 00007f08b938f639 RDX: 0000200000000480 RSI: 00000000ffffff9c RDI: 0000200000000440 RBP: 00000000000f4240 R08: 0000000000000009 R09: 0000000000000009 R10: 0000000000000009 R11: 0000000000000246 R12: 0000000000027904 R13: 00007fff52171fbc R14: 00007fff52171fd0 R15: 00007fff52171fc0 Allocated by task 5712: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x3d5/0x680 mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] nvmet_ports_make+0xe6/0xf00 drivers/nvme/target/configfs.c:2054 configfs_mkdir+0x4f6/0x9e0 fs/configfs/dir.c:1369 vfs_mkdir+0x408/0x620 fs/namei.c:5439 filename_mkdirat+0x289/0x520 fs/namei.c:5472 __do_sys_mkdir fs/namei.c:5499 [inline] __se_sys_mkdir+0x34/0x150 fs/namei.c:5496 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 Freed by task 5712: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:264 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6509 [inline] kfree+0x1c5/0x6d0 mm/slub.c:6802 config_item_cleanup fs/configfs/item.c:128 [inline] config_item_release+0x13a/0x2d0 fs/configfs/item.c:137 configfs_rmdir+0x885/0x950 fs/configfs/dir.c:1580 vfs_rmdir+0x3e9/0x6b0 fs/namei.c:5544 filename_rmdir+0x292/0x520 fs/namei.c:5601 __do_sys_rmdir fs/namei.c:5624 [inline] __se_sys_rmdir+0x2e/0x140 fs/namei.c:5621 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 The buggy address belongs to the object at ffff88803b644000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 1204 bytes inside of freed 4096-byte region [ffff88803b644000, ffff88803b645000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3b640 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813ffbf140 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813ffbf140 dead000000000100 dead000000000122 head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000 head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4964, tgid 4964 (udevd), ts 37671613888 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436 alloc_slab_page mm/slub.c:3347 [inline] allocate_slab+0x7d/0x620 mm/slub.c:3462 new_slab mm/slub.c:3513 [inline] refill_objects+0x2d8/0x350 mm/slub.c:7418 refill_sheaf mm/slub.c:2885 [inline] __pcs_replace_empty_main+0x339/0x690 mm/slub.c:4774 alloc_from_pcs mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:4984 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x54b/0x790 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776 security_file_open+0xa9/0x240 security/security.c:2739 do_dentry_open+0x4be/0x1420 fs/open.c:973 vfs_open+0x3b/0x350 fs/open.c:1101 do_open fs/namei.c:4866 [inline] path_openat+0x1448/0x1d60 fs/namei.c:5029 do_file_open+0x23e/0x4a0 fs/namei.c:5058 do_sys_openat2+0x115/0x200 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1434 page last free pid 4965 tgid 4965 ts 37659265486 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xf8e/0x1070 mm/page_alloc.c:2962 __slab_free+0x250/0x2a0 mm/slub.c:5823 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] __kmalloc_cache_noprof+0x353/0x680 mm/slub.c:5559 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] kernfs_fop_open+0x3a7/0xcf0 fs/kernfs/file.c:634 do_dentry_open+0x849/0x1420 fs/open.c:996 vfs_open+0x3b/0x350 fs/open.c:1101 do_open fs/namei.c:4866 [inline] path_openat+0x1448/0x1d60 fs/namei.c:5029 do_file_open+0x23e/0x4a0 fs/namei.c:5058 do_sys_openat2+0x115/0x200 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1434 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 Memory state around the buggy address: ffff88803b644380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803b644400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803b644480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803b644500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803b644580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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