comedi comedi3: c6xdigio: I/O port conflict (0x401,3) ================================================================== BUG: KASAN: slab-use-after-free in sysfs_remove_file_ns+0x63/0x70 fs/sysfs/file.c:510 Read of size 8 at addr ffff88803125c230 by task syz.2.3876/21391 CPU: 0 UID: 0 PID: 21391 Comm: syz.2.3876 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 sysfs_remove_file_ns+0x63/0x70 fs/sysfs/file.c:510 sysfs_remove_file include/linux/sysfs.h:770 [inline] driver_remove_file drivers/base/driver.c:201 [inline] driver_remove_file+0x4a/0x60 drivers/base/driver.c:197 remove_bind_files drivers/base/bus.c:605 [inline] bus_remove_driver+0x224/0x2c0 drivers/base/bus.c:743 driver_unregister+0x76/0xb0 drivers/base/driver.c:277 comedi_device_detach_locked+0x12f/0xa50 drivers/comedi/drivers.c:207 comedi_device_detach+0x67/0xb0 drivers/comedi/drivers.c:215 comedi_device_attach+0x43d/0x900 drivers/comedi/drivers.c:1011 do_devconfig_ioctl+0x1b1/0x710 drivers/comedi/comedi_fops.c:872 comedi_unlocked_ioctl+0x165d/0x2f00 drivers/comedi/comedi_fops.c:2178 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcc42f8f6c9 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:00007fcc43d75038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fcc431e6180 RCX: 00007fcc42f8f6c9 RDX: 0000200000000080 RSI: 0000000040946400 RDI: 0000000000000006 RBP: 00007fcc43011f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcc431e6218 R14: 00007fcc431e6180 R15: 00007ffeb9dee818 Allocated by task 21103: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5646 [inline] __kmalloc_noprof+0x32f/0x880 mm/slub.c:5658 kmalloc_noprof include/linux/slab.h:961 [inline] io_cache_alloc_new+0x45/0xf0 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:323 [inline] io_rw_alloc_async io_uring/rw.c:202 [inline] __io_prep_rw+0x21d/0x1090 io_uring/rw.c:261 io_prep_rw+0x76/0x2c0 io_uring/rw.c:322 io_prep_rwv io_uring/rw.c:344 [inline] io_prep_readv+0x20/0xa0 io_uring/rw.c:359 io_init_req io_uring/io_uring.c:2248 [inline] io_submit_sqe io_uring/io_uring.c:2295 [inline] io_submit_sqes+0x855/0x2710 io_uring/io_uring.c:2447 __do_sys_io_uring_enter+0xd69/0x1630 io_uring/io_uring.c:3514 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 21103: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 __kasan_save_free_info+0x3b/0x60 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+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2539 [inline] slab_free mm/slub.c:6634 [inline] kfree+0x2b8/0x6d0 mm/slub.c:6841 io_clean_op io_uring/io_uring.c:416 [inline] io_free_batch_list io_uring/io_uring.c:1531 [inline] __io_submit_flush_completions+0x1482/0x1980 io_uring/io_uring.c:1569 io_submit_flush_completions io_uring/io_uring.h:220 [inline] io_submit_state_end io_uring/io_uring.c:2348 [inline] io_submit_sqes+0xa0e/0x2710 io_uring/io_uring.c:2462 __do_sys_io_uring_enter+0xd69/0x1630 io_uring/io_uring.c:3514 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803125c200 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff88803125c200, ffff88803125c300) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803125ce00 pfn:0x3125c 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 ffff88813ffa6b40 ffffea0000d08a10 ffffea0000c6e210 raw: ffff88803125ce00 000000000010000e 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88813ffa6b40 ffffea0000d08a10 ffffea0000c6e210 head: ffff88803125ce00 000000000010000e 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000c49701 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5182, tgid 5182 (udevd), ts 70049457810, free_ts 70020049159 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x10a3/0x3a30 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x25f/0x2470 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3055 [inline] allocate_slab mm/slub.c:3228 [inline] new_slab+0x24a/0x360 mm/slub.c:3282 ___slab_alloc+0xd79/0x1a50 mm/slub.c:4651 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5272 [inline] __kmalloc_cache_noprof+0x477/0x780 mm/slub.c:5762 kmalloc_noprof include/linux/slab.h:957 [inline] inode_doinit_use_xattr+0x54/0x410 security/selinux/hooks.c:1370 inode_doinit_with_dentry+0x10c8/0x12e0 security/selinux/hooks.c:1564 selinux_d_instantiate+0x26/0x30 security/selinux/hooks.c:6523 security_d_instantiate+0x142/0x1a0 security/security.c:4148 d_splice_alias_ops+0x92/0x840 fs/dcache.c:3001 kernfs_iop_lookup+0x23f/0x2d0 fs/kernfs/dir.c:1251 __lookup_slow+0x251/0x460 fs/namei.c:1816 lookup_slow fs/namei.c:1833 [inline] walk_component+0x353/0x5b0 fs/namei.c:2151 page last free pid 5182 tgid 5182 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0x7df/0x1160 mm/page_alloc.c:2906 discard_slab mm/slub.c:3326 [inline] __put_partials+0x130/0x170 mm/slub.c:3872 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4974 [inline] slab_alloc_node mm/slub.c:5284 [inline] kmem_cache_alloc_noprof+0x250/0x6e0 mm/slub.c:5291 getname_flags.part.0+0x4c/0x550 fs/namei.c:146 getname_flags+0x93/0xf0 include/linux/audit.h:345 do_readlinkat+0xb4/0x3a0 fs/stat.c:575 __do_sys_readlink fs/stat.c:613 [inline] __se_sys_readlink fs/stat.c:610 [inline] __x64_sys_readlink+0x78/0xc0 fs/stat.c:610 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88803125c100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88803125c180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88803125c200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803125c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803125c300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================