================================================================== BUG: KASAN: slab-use-after-free in __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] BUG: KASAN: slab-use-after-free in _raw_spin_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:170 Read of size 1 at addr ffff88802f5e38b0 by task syz.8.2786/23300 CPU: 0 UID: 0 PID: 23300 Comm: syz.8.2786 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x230 mm/kasan/report.c:480 kasan_report+0x118/0x150 mm/kasan/report.c:593 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:557 kasan_check_byte include/linux/kasan.h:399 [inline] lock_acquire+0x8d/0x360 kernel/locking/lockdep.c:5845 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:376 [inline] io_poll_remove_entry io_uring/poll.c:146 [inline] io_poll_remove_entries+0x1eb/0x620 io_uring/poll.c:179 io_poll_task_func+0x912/0xf30 io_uring/poll.c:326 io_handle_tw_list+0x1f5/0x4c0 io_uring/io_uring.c:1067 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+0x1d4/0x260 kernel/task_work.c:227 get_signal+0x11ed/0x1340 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 RIP: 0033:0x7ff23658e9a9 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:00007ff2343d5038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: 0000000000000100 RBX: 00007ff2367b6080 RCX: 00007ff23658e9a9 RDX: 0000000000000000 RSI: 00000000000047ba RDI: 0000000000000003 RBP: 00007ff236610d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff2367b6080 R15: 00007fff6026eb18 Allocated by task 23296: 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] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] __comedi_device_postconfig_async drivers/comedi/drivers.c:667 [inline] __comedi_device_postconfig drivers/comedi/drivers.c:724 [inline] comedi_device_postconfig+0x4a8/0xc90 drivers/comedi/drivers.c:759 comedi_device_attach+0x53a/0x670 drivers/comedi/drivers.c:1001 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 Freed by task 23307: 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 comedi_device_detach_cleanup drivers/comedi/drivers.c:171 [inline] comedi_device_detach+0x372/0x720 drivers/comedi/drivers.c:208 do_devconfig_ioctl drivers/comedi/comedi_fops.c:833 [inline] comedi_unlocked_ioctl+0xbd2/0xfc0 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 The buggy address belongs to the object at ffff88802f5e3800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 176 bytes inside of freed 256-byte region [ffff88802f5e3800, ffff88802f5e3900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2f5e2 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 ksm flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801a441b40 ffffea0001e34e00 dead000000000007 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801a441b40 ffffea0001e34e00 dead000000000007 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000bd7881 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 16064, tgid 16054 (syz.7.1638), ts 1323656076474, free_ts 1323458546211 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+0x21e4/0x22c0 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] __do_kmalloc_node mm/slub.c:4327 [inline] __kmalloc_node_track_caller_noprof+0x2f8/0x4e0 mm/slub.c:4347 __do_krealloc mm/slub.c:4905 [inline] krealloc_noprof+0x124/0x340 mm/slub.c:4958 copy_array+0x63/0xf0 kernel/bpf/verifier.c:1381 copy_stack_state kernel/bpf/verifier.c:1441 [inline] copy_func_state kernel/bpf/verifier.c:1727 [inline] copy_verifier_state+0x848/0xed0 kernel/bpf/verifier.c:1768 push_stack+0x197/0x3c0 kernel/bpf/verifier.c:2033 check_cond_jmp_op+0x1069/0x2340 kernel/bpf/verifier.c:16538 do_check+0x6d3a/0xd450 kernel/bpf/verifier.c:19700 do_check_common+0x168d/0x20b0 kernel/bpf/verifier.c:22807 do_check_main kernel/bpf/verifier.c:22898 [inline] bpf_check+0x13664/0x19c60 kernel/bpf/verifier.c:24064 bpf_prog_load+0x1318/0x1930 kernel/bpf/syscall.c:2972 page last free pid 14076 tgid 14076 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706 __slab_free+0x326/0x400 mm/slub.c:4554 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:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 getname_flags+0xb8/0x540 fs/namei.c:146 user_path_at+0x24/0x60 fs/namei.c:3135 ksys_umount fs/namespace.c:2147 [inline] __do_sys_umount fs/namespace.c:2155 [inline] __se_sys_umount fs/namespace.c:2153 [inline] __x64_sys_umount+0xee/0x160 fs/namespace.c:2153 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 Memory state around the buggy address: ffff88802f5e3780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802f5e3800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802f5e3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802f5e3900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802f5e3980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================