From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f78.google.com (mail-ot1-f78.google.com [209.85.210.78]) (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 015DC17C203 for ; Wed, 12 Aug 2026 03:37:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786505851; cv=none; b=cjZeeqG7P8PXT0piVZ3PD+fftFGH1XoAGx3IZ6gDoFnzKGwGIrBoO9OP3i9z9cNGvrTug40O+zL3actmQBsJ0VIc+4Pb16izmZ/r4BM5tXGt83u7asC3nZgim20bkpvmV/ixNkUJhPZKFyE6SnoixgEtp9zhdHuoY1TBt0yy/uA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786505851; c=relaxed/simple; bh=MIIv0xTsnqrlcOqyj+16SH2+uxr6/WmnsMqFNsm4JQQ=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=N3L6tJXzefxU8VignIGxrALaTeZRF/+kdBApHjRlfhfBXsT5LU8pLiDNKANfqEsghx7oUZhFt/r2DUjde/g/CKhwhZ0g4iPshGip1ZyAsiIe4q1VVLIlsw3qIKzp3J8/m4O8UrKB+TbV3q137/CGaPSfZ0eu6FgQnNpCLO4NS34= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.210.78 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-ot1-f78.google.com with SMTP id 46e09a7af769-7f1da5e5b06so834275a34.2 for ; Tue, 11 Aug 2026 20:37:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786505849; x=1787110649; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=ChoZOIGRpaanleIA8dSnWFxb+ZH3l02iHTvKOEzop/Q=; b=Qt7ItB2ufK/RYzAYX8dObPGCbeU3IVUJbWf9wF44CMvqXMBHuSiZ69zJYib+1soNp9 lxN8jyH/KP0THNDpSSnMRLybQuzKYg6YJqQO83itxZP1kbMg8Fz7CG0mj1KHG7ZV66we CWX1IcSTolnAM2wbJlRdVyQMvXyZaZhPcAY1O/nKVG+qTf2sOJ883SFiDiOG9tVx7kSD 9GrSCJSxyiaNmNDYwhU4e7QiX/t39QySQzWGa1ztRPSObcHyKCF6FBzJm656Cy9xvmLH IRqzuCxV6dgCYaxRrNP0wNkv0y7ayBJs0G04fhYNxUhYtM1opbwxrUtq8kWGkE2DThqW 9Ykg== X-Forwarded-Encrypted: i=1; AHgh+RqHIxCvTly+hTgx7kX3drtL+FiAdk3BoybQT85IFO8Z1UKYXPh7UuVcDpnLiT+LBfXOLgtv3p6eEMFX7yQ=@vger.kernel.org X-Gm-Message-State: AOJu0YysOgR+2/FkrAQ4QJKnLoSPT8ECfAQGSPk+obPcRnOUtQGQeHd0 KtwL5dBmIeo3hQP0G9WAzNzjwExB8yJVDIJQGME1KF39jlY57r5MGg6ULp2HdNGlIlrx3ImvToH kTCyik0vD6nTULM36ciLxq6NrgGxIR2P37EQ7e9u2hM5v3lefe13AUep2J18= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:61d:b0:6ae:a950:9fb4 with SMTP id 006d021491bc7-6b0b2946de0mr1417619eaf.33.1786505848881; Tue, 11 Aug 2026 20:37:28 -0700 (PDT) Date: Tue, 11 Aug 2026 20:37:28 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7bea78.d5f0ebe7.22d851.0007.GAE@google.com> Subject: [syzbot] [fuse?] KASAN: slab-use-after-free Read in fuse_dev_do_write From: syzbot To: fuse-devel@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: c21bb4193868 Merge tag 'for_linus' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=104a0e49580000 kernel config: https://syzkaller.appspot.com/x/.config?x=4e38b15c29e6a1d9 dashboard link: https://syzkaller.appspot.com/bug?extid=d6540a3fa1626e11360d compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/cf4c0f46390e/disk-c21bb419.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/21802e5d4446/vmlinux-c21bb419.xz kernel image: https://storage.googleapis.com/syzbot-assets/6c46db810c9d/bzImage-c21bb419.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d6540a3fa1626e11360d@syzkaller.appspotmail.com ================================================================== BUG: KASAN: slab-use-after-free in fuse_dev_do_write+0xb54/0xbf0 fs/fuse/dev.c:1940 Read of size 2 at addr ffff88802990801b by task syz.6.1795/14368 CPU: 0 UID: 0 PID: 14368 Comm: syz.6.1795 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 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 fuse_dev_do_write+0xb54/0xbf0 fs/fuse/dev.c:1940 fuse_dev_write+0x18c/0x230 fs/fuse/dev.c:1981 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:739 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: 0033:0x7f274015e90e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007f27410d9f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f27410da6c0 RCX: 00007f274015e90e RDX: 0000000000000050 RSI: 0000200000006100 RDI: 0000000000000005 RBP: 0000000000000068 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005 R13: 0000200000006d80 R14: 00007f2740425fa0 R15: 00007ffc707d4e08 Allocated by task 14378: 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:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x32d/0x660 mm/slub.c:5489 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] fuse_new_init fs/fuse/inode.c:1445 [inline] fuse_send_init+0x58/0x820 fs/fuse/inode.c:1506 vfs_get_super fs/super.c:1273 [inline] get_tree_nodev+0xbb/0x150 fs/super.c:1292 fuse_get_tree+0x29d/0x3b0 fs/fuse/inode.c:1899 vfs_get_tree+0x92/0x2a0 fs/super.c:1700 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3765 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3841 do_mount fs/namespace.c:4174 [inline] __do_sys_mount fs/namespace.c:4390 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4367 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 Freed by task 14378: 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:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x1c5/0x640 mm/slub.c:6692 process_init_reply+0x174/0x21b0 fs/fuse/inode.c:1424 fuse_send_init+0x506/0x820 fs/fuse/inode.c:1521 vfs_get_super fs/super.c:1273 [inline] get_tree_nodev+0xbb/0x150 fs/super.c:1292 fuse_get_tree+0x29d/0x3b0 fs/fuse/inode.c:1899 vfs_get_tree+0x92/0x2a0 fs/super.c:1700 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3765 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3841 do_mount fs/namespace.c:4174 [inline] __do_sys_mount fs/namespace.c:4390 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4367 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 The buggy address belongs to the object at ffff888029908000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 27 bytes inside of freed 512-byte region [ffff888029908000, ffff888029908200) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29908 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b001c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b001c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 11745940408, free_ts 11745170687 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab+0x79/0x5e0 mm/slub.c:3380 new_slab mm/slub.c:3426 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x2bf/0x6b0 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __kmalloc_cache_noprof+0x3a7/0x660 mm/slub.c:5485 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] device_private_init drivers/base/core.c:3602 [inline] device_add+0xb6/0xb80 drivers/base/core.c:3653 workqueue_sysfs_register+0x12b/0x300 kernel/workqueue.c:7614 __alloc_workqueue+0x1c75/0x2060 kernel/workqueue.c:5911 alloc_workqueue_va kernel/workqueue.c:5946 [inline] alloc_workqueue_noprof+0xe3/0x210 kernel/workqueue.c:5962 tty_register_driver+0x2f0/0xdf0 drivers/tty/tty_io.c:3451 usb_serial_init+0x1e3/0x350 drivers/usb/serial/usb-serial.c:1339 do_one_initcall+0x250/0x870 init/main.c:1347 do_initcall_level+0x10a/0x1a0 init/main.c:1409 do_initcalls+0x59/0xa0 init/main.c:1425 page last free pid 13 tgid 13 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950 sbitmap_free include/linux/sbitmap.h:188 [inline] scsi_device_dev_release+0x5c8/0xee0 drivers/scsi/scsi_sysfs.c:481 device_release+0xc4/0x1f0 drivers/base/core.c:-1 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x222/0x550 lib/kobject.c:737 scsi_probe_and_add_lun+0x31cb/0x4b10 drivers/scsi/scsi_scan.c:-1 __scsi_scan_target+0x1f0/0xe10 drivers/scsi/scsi_scan.c:1797 scsi_scan_channel drivers/scsi/scsi_scan.c:1885 [inline] scsi_scan_host_selected+0x3d3/0x7a0 drivers/scsi/scsi_scan.c:1914 do_scsi_scan_host drivers/scsi/scsi_scan.c:2047 [inline] do_scan_async+0x10e/0x660 drivers/scsi/scsi_scan.c:2057 async_run_entry_fn+0x9d/0x430 kernel/async.c:129 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888029907f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888029907f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888029908000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888029908080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888029908100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. 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