RAX: ffffffffffffffda RBX: 00007fafc9bd5fa0 RCX: 00007fafc998eba9 RDX: 00002000000000c0 RSI: 0000000040946400 RDI: 0000000000000003 RBP: 00007fafca75c090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fafc9bd6038 R14: 00007fafc9bd5fa0 R15: 00007ffd5ba48788 comedi comedi3: c6xdigio: I/O port conflict (0x4f27,3) ================================================================== BUG: KASAN: slab-use-after-free in sysfs_remove_file_ns+0x3d/0x70 fs/sysfs/file.c:510 Read of size 8 at addr ffff888077677c30 by task syz.2.4775/19595 CPU: 0 UID: 0 PID: 19595 Comm: syz.2.4775 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 sysfs_remove_file_ns+0x3d/0x70 fs/sysfs/file.c:510 remove_bind_files drivers/base/bus.c:605 [inline] bus_remove_driver+0x198/0x2f0 drivers/base/bus.c:743 comedi_device_detach_locked+0x175/0x750 drivers/comedi/drivers.c:207 comedi_device_detach drivers/comedi/drivers.c:215 [inline] comedi_device_attach+0x5d4/0x720 drivers/comedi/drivers.c:1011 do_devconfig_ioctl drivers/comedi/comedi_fops.c:872 [inline] comedi_unlocked_ioctl+0x5ff/0x1020 drivers/comedi/comedi_fops.c:2178 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fafc998eba9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fafca75c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fafc9bd5fa0 RCX: 00007fafc998eba9 RDX: 00002000000000c0 RSI: 0000000040946400 RDI: 0000000000000003 RBP: 00007fafca75c090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fafc9bd6038 R14: 00007fafc9bd5fa0 R15: 00007ffd5ba48788 Allocated by task 18061: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5397 kmalloc_noprof include/linux/slab.h:956 [inline] kzalloc_noprof include/linux/slab.h:1090 [inline] __mmu_notifier_register+0x348/0x5f0 mm/mmu_notifier.c:621 mmu_notifier_register+0x70/0x1e0 mm/mmu_notifier.c:705 kvm_init_mmu_notifier virt/kvm/kvm_main.c:900 [inline] kvm_create_vm virt/kvm/kvm_main.c:1196 [inline] kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5482 [inline] kvm_dev_ioctl+0x13b9/0x18e0 virt/kvm/kvm_main.c:5524 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 18061: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2484 [inline] slab_free mm/slub.c:6121 [inline] kfree+0x199/0x6d0 mm/slub.c:6329 __mmu_notifier_subscriptions_destroy+0x66/0xa0 mm/mmu_notifier.c:783 mmu_notifier_subscriptions_destroy include/linux/mmu_notifier.h:490 [inline] __mmdrop+0x152/0x570 kernel/fork.c:701 exit_mm+0x1da/0x2c0 kernel/exit.c:582 do_exit+0x648/0x2300 kernel/exit.c:954 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107 get_signal+0x1286/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888077677c00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff888077677c00, ffff888077677d00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888077676400 pfn:0x77676 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801a841b40 ffffea0001ee2890 ffffea0000cfa810 raw: ffff888077676400 000000000010000e 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801a841b40 ffffea0001ee2890 ffffea0000cfa810 head: ffff888077676400 000000000010000e 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0001dd9d81 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5858, tgid 5858 (syz-executor), ts 91330182273, free_ts 91302287971 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3863 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5153 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2996 [inline] allocate_slab+0x8a/0x330 mm/slub.c:3164 new_slab mm/slub.c:3218 [inline] ___slab_alloc+0xbd1/0x13f0 mm/slub.c:4420 __slab_alloc+0x55/0xa0 mm/slub.c:4511 __slab_alloc_node mm/slub.c:4586 [inline] slab_alloc_node mm/slub.c:4996 [inline] __do_kmalloc_node mm/slub.c:5365 [inline] __kmalloc_noprof+0x471/0x7f0 mm/slub.c:5378 kmalloc_noprof include/linux/slab.h:960 [inline] kzalloc_noprof include/linux/slab.h:1090 [inline] fib_create_info+0x172d/0x3210 net/ipv4/fib_semantics.c:1402 fib_table_insert+0xc6/0x1b50 net/ipv4/fib_trie.c:1212 fib_magic+0x2c4/0x390 net/ipv4/fib_frontend.c:1134 fib_add_ifaddr+0x144/0x5f0 net/ipv4/fib_frontend.c:1156 fib_inetaddr_event+0x12e/0x190 net/ipv4/fib_frontend.c:1470 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380 __inet_insert_ifa+0xa13/0xbf0 net/ipv4/devinet.c:566 page last free pid 5862 tgid 5862 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2900 __slab_free+0x2e7/0x390 mm/slub.c:5596 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:349 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4710 [inline] slab_alloc_node mm/slub.c:5008 [inline] kmem_cache_alloc_node_noprof+0x433/0x710 mm/slub.c:5060 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:659 alloc_skb include/linux/skbuff.h:1377 [inline] nlmsg_new include/net/netlink.h:1055 [inline] netlink_ack+0x146/0xa50 net/netlink/af_netlink.c:2489 netlink_rcv_skb+0x28c/0x470 net/netlink/af_netlink.c:2558 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82c/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:729 __sys_sendto+0x3bd/0x520 net/socket.c:2228 __do_sys_sendto net/socket.c:2235 [inline] __se_sys_sendto net/socket.c:2231 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2231 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888077677b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888077677b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888077677c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888077677c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888077677d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================