================================================================== BUG: KASAN: slab-use-after-free in fuse_dev_do_read+0x11e9/0x1260 fs/fuse/dev.c:1608 Read of size 1 at addr ffff88805e524418 by task syz.1.640/8957 CPU: 1 UID: 0 PID: 8957 Comm: syz.1.640 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 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_read+0x11e9/0x1260 fs/fuse/dev.c:1608 fuse_dev_read+0x16a/0x200 fs/fuse/dev.c:1694 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x59e/0xa90 fs/read_write.c:574 ksys_read+0x156/0x270 fs/read_write.c:716 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd8b2ece6ce 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:00007fd8b1165f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fd8b11666c0 RCX: 00007fd8b2ece6ce RDX: 0000000000002000 RSI: 0000200000004100 RDI: 0000000000000003 RBP: 00007fd8b2fa3eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000200000006d80 R14: 00007fd8b3195fa0 R15: 00007fff73dbdb98 Allocated by task 8963: 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+0x3cd/0x670 mm/slub.c:5486 _kmalloc_noprof include/linux/slab.h:969 [inline] _kzalloc_noprof include/linux/slab.h:1290 [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:1399 [inline] get_tree_nodev+0xbb/0x150 fs/super.c:1418 fuse_get_tree+0x29d/0x3b0 fs/fuse/inode.c:1899 vfs_get_tree+0x92/0x2a0 fs/super.c:1941 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3777 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3853 do_mount fs/namespace.c:4186 [inline] __do_sys_mount fs/namespace.c:4402 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4379 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 8963: 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:2706 [inline] slab_free mm/slub.c:6388 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6703 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:1399 [inline] get_tree_nodev+0xbb/0x150 fs/super.c:1418 fuse_get_tree+0x29d/0x3b0 fs/fuse/inode.c:1899 vfs_get_tree+0x92/0x2a0 fs/super.c:1941 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3777 [inline] do_new_mount+0x319/0xdc0 fs/namespace.c:3853 do_mount fs/namespace.c:4186 [inline] __do_sys_mount fs/namespace.c:4402 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4379 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88805e524400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 24 bytes inside of freed 512-byte region [ffff88805e524400, ffff88805e524600) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5e524 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813feaec80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813feaec80 dead000000000100 dead000000000122 head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 0080000000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: 0000000000000000 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 1474, tgid 1474 (kworker/u8:11), ts 117958256176 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+0x264c/0x26c0 mm/page_alloc.c:3955 __alloc_frozen_pages_noprof+0x222/0x5b0 mm/page_alloc.c:5394 alloc_slab_page mm/slub.c:3295 [inline] allocate_slab+0x7c/0x5e0 mm/slub.c:3410 new_slab mm/slub.c:3456 [inline] refill_objects+0x2d8/0x350 mm/slub.c:7321 refill_sheaf mm/slub.c:2833 [inline] __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4699 alloc_from_pcs mm/slub.c:4775 [inline] slab_alloc_node mm/slub.c:4909 [inline] __kmalloc_cache_noprof+0x467/0x670 mm/slub.c:5482 _kmalloc_noprof include/linux/slab.h:969 [inline] _kzalloc_noprof include/linux/slab.h:1290 [inline] mca_alloc net/ipv6/mcast.c:871 [inline] __ipv6_dev_mc_inc+0x447/0xa40 net/ipv6/mcast.c:962 addrconf_join_solict net/ipv6/addrconf.c:2262 [inline] addrconf_dad_begin net/ipv6/addrconf.c:4134 [inline] addrconf_dad_work+0x5dd/0x16e0 net/ipv6/addrconf.c:4262 process_one_work+0xaaf/0x1480 kernel/workqueue.c:3379 process_scheduled_works kernel/workqueue.c:3462 [inline] worker_thread+0xb05/0x10d0 kernel/workqueue.c:3543 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 page last free pid 5838 tgid 5838 ts 117954945616 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0x1185/0x1270 mm/page_alloc.c:2962 __slab_free+0x252/0x2a0 mm/slub.c:5738 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:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4608 [inline] slab_alloc_node mm/slub.c:4921 [inline] kmem_cache_alloc_noprof+0x358/0x680 mm/slub.c:4935 lsm_file_alloc security/security.c:171 [inline] security_file_alloc+0x34/0x2d0 security/security.c:2406 init_file+0x96/0x2d0 fs/file_table.c:184 alloc_empty_file+0x74/0x1d0 fs/file_table.c:266 path_openat+0x8f/0x3850 fs/namei.c:4843 do_file_open+0x23e/0x4a0 fs/namei.c:4886 do_sys_openat2+0x115/0x200 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1385 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88805e524300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88805e524380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88805e524400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805e524480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805e524500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================