comedi comedi0: c6xdigio: I/O port conflict (0x4f2b,3) ================================================================== BUG: KASAN: slab-use-after-free in sysfs_remove_file_ns+0x3d/0x70 fs/sysfs/file.c:522 Read of size 8 at addr ffff88803285a030 by task syz.0.1501/11525 CPU: 0 UID: 0 PID: 11525 Comm: syz.0.1501 Not tainted 6.16.0-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:522 remove_bind_files drivers/base/bus.c:605 [inline] bus_remove_driver+0x198/0x2f0 drivers/base/bus.c:743 comedi_device_detach+0x134/0x720 drivers/comedi/drivers.c:207 comedi_device_attach+0x568/0x670 drivers/comedi/drivers.c:1003 do_devconfig_ioctl drivers/comedi/comedi_fops.c:855 [inline] comedi_unlocked_ioctl+0x686/0xfc0 drivers/comedi/comedi_fops.c:2156 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6d6eb8ebe9 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:00007f6d6f920038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f6d6edb6090 RCX: 00007f6d6eb8ebe9 RDX: 00002000000000c0 RSI: 0000000040946400 RDI: 0000000000000006 RBP: 00007f6d6ec11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6d6edb6128 R14: 00007f6d6edb6090 R15: 00007ffc76849058 Allocated by task 11143: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4328 [inline] __kmalloc_noprof+0x27a/0x4f0 mm/slub.c:4340 kmalloc_noprof include/linux/slab.h:909 [inline] io_cache_alloc_new+0x40/0x100 io_uring/alloc_cache.c:40 io_cache_alloc io_uring/alloc_cache.h:59 [inline] io_uring_alloc_async_data io_uring/io_uring.h:245 [inline] io_rw_alloc_async io_uring/rw.c:202 [inline] __io_prep_rw+0x23f/0xd80 io_uring/rw.c:261 io_prep_rw io_uring/rw.c:320 [inline] io_prep_rwv+0x8c/0x3d0 io_uring/rw.c:342 io_init_req io_uring/io_uring.c:2139 [inline] io_submit_sqe io_uring/io_uring.c:2186 [inline] io_submit_sqes+0x90c/0x1c50 io_uring/io_uring.c:2337 __do_sys_io_uring_enter io_uring/io_uring.c:3404 [inline] __se_sys_io_uring_enter+0x2df/0x2b20 io_uring/io_uring.c:3338 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 11143: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x18e/0x440 mm/slub.c:4842 io_clean_op+0x386/0x400 io_uring/io_uring.c:405 io_free_batch_list io_uring/io_uring.c:1445 [inline] __io_submit_flush_completions+0xc20/0xe40 io_uring/io_uring.c:1483 io_submit_flush_completions io_uring/io_uring.h:163 [inline] ctx_flush_and_put+0xec/0x150 io_uring/io_uring.c:1039 io_handle_tw_list+0x2bc/0x4c0 io_uring/io_uring.c:1073 tctx_task_work_run+0x99/0x370 io_uring/io_uring.c:1132 tctx_task_work+0x3f/0x90 io_uring/io_uring.c:1150 task_work_run+0x1d1/0x260 kernel/task_work.c:227 get_signal+0x11c5/0x1310 kernel/signal.c:2807 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:111 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803285a000 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff88803285a000, ffff88803285a100) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803285a000 pfn:0x3285a 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 ffff88801a441b40 ffffea00009fe310 ffffea00008f4710 raw: ffff88803285a000 000000000010000c 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801a441b40 ffffea00009fe310 ffffea00008f4710 head: ffff88803285a000 000000000010000c 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000ca1681 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5828, tgid 5828 (kworker/1:3), ts 95475303833, free_ts 95414218885 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704 prep_new_page mm/page_alloc.c:1712 [inline] get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419 alloc_slab_page mm/slub.c:2451 [inline] allocate_slab+0x8a/0x3b0 mm/slub.c:2619 new_slab mm/slub.c:2673 [inline] ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859 __slab_alloc mm/slub.c:3949 [inline] __slab_alloc_node mm/slub.c:4024 [inline] slab_alloc_node mm/slub.c:4185 [inline] __kmalloc_cache_noprof+0x296/0x3d0 mm/slub.c:4354 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] br_multicast_new_group+0x13d/0x4b0 net/bridge/br_multicast.c:1295 __br_multicast_add_group+0x285/0xa30 net/bridge/br_multicast.c:1520 br_multicast_add_group net/bridge/br_multicast.c:1569 [inline] br_ip6_multicast_add_group net/bridge/br_multicast.c:1621 [inline] br_ip6_multicast_mld2_report net/bridge/br_multicast.c:3047 [inline] br_multicast_ipv6_rcv net/bridge/br_multicast.c:3985 [inline] br_multicast_rcv+0x3a5f/0x74b0 net/bridge/br_multicast.c:4043 br_dev_xmit+0xaf7/0x1840 net/bridge/br_device.c:98 __netdev_start_xmit include/linux/netdevice.h:5215 [inline] netdev_start_xmit include/linux/netdevice.h:5224 [inline] xmit_one net/core/dev.c:3830 [inline] dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3846 __dev_queue_xmit+0x1adf/0x3a70 net/core/dev.c:4713 dev_queue_xmit include/linux/netdevice.h:3355 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip6_finish_output2+0x11bc/0x16a0 net/ipv6/ip6_output.c:141 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:317 mld_sendpack+0x800/0xd80 net/ipv6/mcast.c:1868 page last free pid 23 tgid 23 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0xc65/0xe60 mm/page_alloc.c:2706 rcu_do_batch kernel/rcu/tree.c:2576 [inline] rcu_core+0xca5/0x1710 kernel/rcu/tree.c:2832 handle_softirqs+0x283/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:164 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888032859f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888032859f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88803285a000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803285a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803285a100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================