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AKwUvBwVDzEu43mN9/HYKhoKfBijBBrMpvYxO86ua88iZj0HVKWuKpFa4vwfOOZL7zlcJ7IHvgdRXUWlZkhqlMs=@vger.kernel.org X-Gm-Message-State: AFuF++lgmZYE/eFy4gexYiI8nrrbOVA5xEr2CPvTolnbGnw37xWjg24y OQ/tsNwcB3y2oJDEKaBeoAgx2FRO/D5504FwKFSfH+S3sULqi0bTdLA0I35nTPgGaHpqXZtFKAz yAMqjGdVZSg2LBiUbgcyO8uwWdSg2Zb/UiLqFBJrhU9oMNxn0IQYitzUePHA= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:198e:b0:4c4:d8a0:2773 with SMTP id 5614622812f47-4c7b626a8efmr220367b6e.32.1789351383436; Sun, 13 Sep 2026 19:03:03 -0700 (PDT) Date: Sun, 13 Sep 2026 19:03:03 -0700 In-Reply-To: <6aa74ffd.2cd27cd2.290120.3dbeSMTPIN_ADDED_BROKEN@gmr-mx.google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6aa755d7.a211d2ce.1a5198.0289.GAE@google.com> Subject: Re: [syzbot] [fs?] KASAN: slab-use-after-free Write in config_item_get From: syzbot To: jchuang26@m.fudan.edu.cn, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: KASAN: slab-use-after-free Write in config_item_get ================================================================== 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_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline] BUG: KASAN: slab-use-after-free in __refcount_add include/linux/refcount.h:283 [inline] BUG: KASAN: slab-use-after-free in __refcount_inc include/linux/refcount.h:366 [inline] BUG: KASAN: slab-use-after-free in refcount_inc include/linux/refcount.h:383 [inline] BUG: KASAN: slab-use-after-free in kref_get include/linux/kref.h:45 [inline] BUG: KASAN: slab-use-after-free in config_item_get+0x26/0x90 fs/configfs/item.c:104 Write of size 4 at addr ffff88804491f01c by task syz.1.545/7868 CPU: 1 UID: 0 PID: 7868 Comm: syz.1.545 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/08/2026 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_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline] __refcount_add include/linux/refcount.h:283 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] kref_get include/linux/kref.h:45 [inline] config_item_get+0x26/0x90 fs/configfs/item.c:104 get_target fs/configfs/symlink.c:139 [inline] configfs_symlink+0x407/0x11d0 fs/configfs/symlink.c:200 vfs_symlink+0x18b/0x330 fs/namei.c:5794 filename_symlinkat+0x1cd/0x420 fs/namei.c:5819 __do_sys_symlinkat fs/namei.c:5839 [inline] __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5834 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 Tested on: commit: a7c1290e configfs: pin the symlink target's dirent ins.. git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git console output: https://syzkaller.appspot.com/x/log.txt?x=1626c115580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6d794b10c2a1184e dashboard link: https://syzkaller.appspot.com/bug?extid=6b16e3d085833cbf3e25 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Note: no patches were applied.