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comedi comedi3: c6xdigio: I/O port conflict (0x3c4,3)
==================================================================
BUG: KASAN: use-after-free in sysfs_remove_file_ns+0x39/0x70 fs/sysfs/file.c:491
Read of size 8 at addr ffff88801df7ae30 by task syz.0.2803/20304

CPU: 1 PID: 20304 Comm: syz.0.2803 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 sysfs_remove_file_ns+0x39/0x70 fs/sysfs/file.c:491
 remove_bind_files drivers/base/bus.c:550 [inline]
 bus_remove_driver+0x89/0x230 drivers/base/bus.c:674
 comedi_device_detach_locked+0x16e/0x710 drivers/comedi/drivers.c:206
 comedi_device_detach drivers/comedi/drivers.c:214 [inline]
 comedi_device_attach+0x5c9/0x700 drivers/comedi/drivers.c:1010
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:868 [inline]
 comedi_unlocked_ioctl+0x5a6/0x1050 drivers/comedi/comedi_fops.c:2173
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4f9498f6c9
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:00007f4f92bf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4f94be6180 RCX: 00007f4f9498f6c9
RDX: 0000200000000080 RSI: 0000000040946400 RDI: 0000000000000008
RBP: 00007f4f94a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4f94be6218 R14: 00007f4f94be6180 R15: 00007ffc9ca93d68
 </TASK>

Allocated by task 17834:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 bus_add_driver+0xda/0x5a0 drivers/base/bus.c:604
 driver_register+0x32d/0x430 drivers/base/driver.c:246
 c6xdigio_attach+0x90/0x880 drivers/comedi/drivers/c6xdigio.c:253
 comedi_device_attach+0x514/0x700 drivers/comedi/drivers.c:1006
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:868 [inline]
 comedi_unlocked_ioctl+0x5a6/0x1050 drivers/comedi/comedi_fops.c:2173
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 20166:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700
 kobject_cleanup lib/kobject.c:681 [inline]
 kobject_release lib/kobject.c:712 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x21d/0x460 lib/kobject.c:729
 bus_remove_driver+0x13c/0x230 drivers/base/bus.c:681
 comedi_device_detach_locked+0x16e/0x710 drivers/comedi/drivers.c:206
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:844 [inline]
 comedi_unlocked_ioctl+0xd0b/0x1050 drivers/comedi/comedi_fops.c:2173
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 call_rcu+0x154/0x980 kernel/rcu/tree.c:2849
 free_fib_info net/ipv4/fib_semantics.c:257 [inline]
 fib_info_put include/net/ip_fib.h:583 [inline]
 fib_release_info+0x684/0x740 net/ipv4/fib_semantics.c:283
 fib_table_delete+0xd7c/0xf80 net/ipv4/fib_trie.c:1757
 fib_magic+0x2e1/0x390 net/ipv4/fib_frontend.c:1120
 fib_del_ifaddr+0x107e/0x1480 net/ipv4/fib_frontend.c:1331
 fib_inetaddr_event+0xb7/0x1c0 net/ipv4/fib_frontend.c:1462
 notifier_call_chain kernel/notifier.c:87 [inline]
 blocking_notifier_call_chain+0x103/0x1b0 kernel/notifier.c:382
 __inet_del_ifa+0x879/0x1020 net/ipv4/devinet.c:445
 inet_del_ifa net/ipv4/devinet.c:482 [inline]
 inetdev_destroy net/ipv4/devinet.c:323 [inline]
 inetdev_event+0x5b7/0x1410 net/ipv4/devinet.c:1615
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
 call_netdevice_notifiers_extack net/core/dev.c:2039 [inline]
 call_netdevice_notifiers net/core/dev.c:2053 [inline]
 unregister_netdevice_many+0xfdc/0x1840 net/core/dev.c:10990
 default_device_exit_batch+0x9c3/0xa50 net/core/dev.c:11503
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x77b/0xb80 net/core/net_namespace.c:640
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 call_rcu+0x154/0x980 kernel/rcu/tree.c:2849
 free_fib_info net/ipv4/fib_semantics.c:257 [inline]
 fib_info_put include/net/ip_fib.h:583 [inline]
 fib_release_info+0x684/0x740 net/ipv4/fib_semantics.c:283
 fib_table_flush+0x9a3/0x11b0 net/ipv4/fib_trie.c:2076
 fib_flush net/ipv4/fib_frontend.c:195 [inline]
 fib_disable_ip+0xfd/0x170 net/ipv4/fib_frontend.c:1440
 fib_netdev_event+0x2f7/0x470 net/ipv4/fib_frontend.c:-1
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
 call_netdevice_notifiers_extack net/core/dev.c:2039 [inline]
 call_netdevice_notifiers net/core/dev.c:2053 [inline]
 dev_close_many+0x28d/0x400 net/core/dev.c:1601
 unregister_netdevice_many+0x471/0x1840 net/core/dev.c:10964
 unregister_netdevice_queue+0x31c/0x360 net/core/dev.c:10921
 unregister_netdevice include/linux/netdevice.h:3075 [inline]
 nsim_destroy+0x49/0x150 drivers/net/netdevsim/netdev.c:382
 __nsim_dev_port_del+0x155/0x1c0 drivers/net/netdevsim/dev.c:1433
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1445 [inline]
 nsim_dev_reload_destroy+0x283/0x480 drivers/net/netdevsim/dev.c:1662
 nsim_drv_remove+0x5c/0x160 drivers/net/netdevsim/dev.c:1678
 device_remove drivers/base/dd.c:548 [inline]
 __device_release_driver drivers/base/dd.c:1260 [inline]
 device_release_driver_internal+0x4be/0x850 drivers/base/dd.c:1286
 bus_remove_device+0x2e2/0x400 drivers/base/bus.c:531
 device_del+0x628/0xa70 drivers/base/core.c:3885
 device_unregister+0x1c/0xc0 drivers/base/core.c:3928
 nsim_bus_dev_del drivers/net/netdevsim/bus.c:310 [inline]
 del_device_store+0x2a7/0x360 drivers/net/netdevsim/bus.c:219
 kernfs_fop_write_iter+0x3b2/0x520 fs/kernfs/file.c:352
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x44c/0x960 fs/read_write.c:584
 ksys_write+0x143/0x240 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88801df7ae00
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 48 bytes inside of
 256-byte region [ffff88801df7ae00, ffff88801df7af00)

The buggy address belongs to the physical page:
page:ffffea000077de80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1df7a
head:ffffea000077de80 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888017441b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
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 4265, tgid 4265 (syz-executor), ts 76929000646, free_ts 76899066271
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614
 alloc_slab_page+0x5d/0x160 mm/slub.c:1799
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x87/0x2c0 mm/slub.c:1997
 ___slab_alloc+0xbc6/0x1230 mm/slub.c:3154
 __slab_alloc mm/slub.c:3240 [inline]
 slab_alloc_node mm/slub.c:3325 [inline]
 __kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398
 __do_kmalloc_node mm/slab_common.c:935 [inline]
 __kmalloc+0xa0/0x240 mm/slab_common.c:949
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 fib_create_info+0xa53/0x2490 net/ipv4/fib_semantics.c:1459
 fib_table_insert+0xc3/0x1b50 net/ipv4/fib_trie.c:1217
 fib_magic+0x2c1/0x390 net/ipv4/fib_frontend.c:1118
 fib_add_ifaddr+0x140/0x5e0 net/ipv4/fib_frontend.c:1140
 fib_inetaddr_event+0x13c/0x1c0 net/ipv4/fib_frontend.c:1454
 notifier_call_chain kernel/notifier.c:87 [inline]
 blocking_notifier_call_chain+0x103/0x1b0 kernel/notifier.c:382
 __inet_insert_ifa+0x9aa/0xb60 net/ipv4/devinet.c:568
 inet_rtm_newaddr+0x930/0x1890 net/ipv4/devinet.c:970
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3479
 free_slab mm/slub.c:2036 [inline]
 discard_slab mm/slub.c:2042 [inline]
 __unfreeze_partials+0x1a5/0x200 mm/slub.c:2591
 put_cpu_partial+0x17c/0x250 mm/slub.c:2667
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x4b/0x480 mm/slab.h:737
 slab_alloc_node mm/slub.c:3359 [inline]
 __kmem_cache_alloc_node+0x140/0x260 mm/slub.c:3398
 __do_kmalloc_node mm/slab_common.c:935 [inline]
 __kmalloc+0xa0/0x240 mm/slab_common.c:949
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 fib6_info_alloc+0x2e/0xe0 net/ipv6/ip6_fib.c:156
 ip6_route_info_create+0x44f/0x1210 net/ipv6/route.c:3794
 ip6_route_add+0x24/0x130 net/ipv6/route.c:3890
 addrconf_add_mroute net/ipv6/addrconf.c:2506 [inline]
 addrconf_add_dev+0x253/0x330 net/ipv6/addrconf.c:2524
 addrconf_dev_config net/ipv6/addrconf.c:3424 [inline]
 addrconf_init_auto_addrs+0x601/0xa60 net/ipv6/addrconf.c:3512
 addrconf_notify+0xaca/0xf40 net/ipv6/addrconf.c:3685

Memory state around the buggy address:
 ffff88801df7ad00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801df7ad80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801df7ae00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88801df7ae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801df7af00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================