================================================================== 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 ==================================================================