================================================================== BUG: KASAN: use-after-free in __lock_acquire+0xf7/0x7c50 kernel/locking/lockdep.c:4919 Read of size 8 at addr ffff8880247d86b8 by task syz.0.18/4428 CPU: 1 PID: 4428 Comm: syz.0.18 Not tainted 6.1.147-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x200 mm/kasan/report.c:418 kasan_report+0x10b/0x140 mm/kasan/report.c:522 __lock_acquire+0xf7/0x7c50 kernel/locking/lockdep.c:4919 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162 remove_wait_queue+0x20/0x120 kernel/sched/wait.c:54 free_poll_entry fs/select.c:132 [inline] poll_freewait+0x99/0x210 fs/select.c:141 do_select+0x1761/0x1850 fs/select.c:609 core_sys_select+0x6ad/0x8b0 fs/select.c:678 do_pselect fs/select.c:760 [inline] __do_sys_pselect6 fs/select.c:801 [inline] __se_sys_pselect6+0x2ed/0x3a0 fs/select.c:792 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: 0033:0x7f3f35f8eb69 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:00007f3f36db1038 EFLAGS: 00000246 ORIG_RAX: 000000000000010e RAX: ffffffffffffffda RBX: 00007f3f361b5fa0 RCX: 00007f3f35f8eb69 RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000040 RBP: 00007f3f36011df1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000000180 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3f361b5fa0 R15: 00007ffe963d6798 Allocated by task 4426: 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] __comedi_device_postconfig_async drivers/comedi/drivers.c:666 [inline] __comedi_device_postconfig drivers/comedi/drivers.c:723 [inline] comedi_device_postconfig+0x496/0xc50 drivers/comedi/drivers.c:758 comedi_device_attach+0x52f/0x650 drivers/comedi/drivers.c:1000 do_devconfig_ioctl drivers/comedi/comedi_fops.c:851 [inline] comedi_unlocked_ioctl+0x5ec/0xf20 drivers/comedi/comedi_fops.c:2151 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 4429: 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:1724 [inline] slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] __kmem_cache_free+0xb6/0x1f0 mm/slub.c:3674 comedi_device_detach_cleanup drivers/comedi/drivers.c:171 [inline] comedi_device_detach+0x35f/0x6e0 drivers/comedi/drivers.c:207 do_devconfig_ioctl drivers/comedi/comedi_fops.c:829 [inline] comedi_unlocked_ioctl+0xb6b/0xf20 drivers/comedi/comedi_fops.c:2151 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 The buggy address belongs to the object at ffff8880247d8600 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 184 bytes inside of 256-byte region [ffff8880247d8600, ffff8880247d8700) The buggy address belongs to the physical page: page:ffffea000091f600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x247d8 head:ffffea000091f600 order:1 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888017441b40 raw: 0000000000000000 0000000080100010 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4425, tgid 4424 (syz.0.17), ts 76897569924, free_ts 76872312605 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:1794 allocate_slab mm/slub.c:1939 [inline] new_slab+0x87/0x2c0 mm/slub.c:1992 ___slab_alloc+0xbc6/0x1220 mm/slub.c:3180 __slab_alloc mm/slub.c:3279 [inline] slab_alloc_node mm/slub.c:3364 [inline] __kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3437 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] snd_rawmidi_runtime_create sound/core/rawmidi.c:164 [inline] open_substream+0xaf/0x6c0 sound/core/rawmidi.c:341 rawmidi_open_priv+0x94/0x660 sound/core/rawmidi.c:389 snd_rawmidi_open+0x44f/0xad0 sound/core/rawmidi.c:492 chrdev_open+0x597/0x670 fs/char_dev.c:414 do_dentry_open+0x7e9/0x10d0 fs/open.c:882 do_open fs/namei.c:3626 [inline] path_openat+0x25c6/0x2e70 fs/namei.c:3783 do_filp_open+0x1c1/0x3c0 fs/namei.c:3810 do_sys_openat2+0x142/0x490 fs/open.c:1318 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 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:3398 [inline] slab_alloc mm/slub.c:3406 [inline] __kmem_cache_alloc_lru mm/slub.c:3413 [inline] kmem_cache_alloc_lru+0x11a/0x2e0 mm/slub.c:3429 alloc_inode_sb include/linux/fs.h:3245 [inline] sock_alloc_inode+0x24/0xc0 net/socket.c:306 alloc_inode fs/inode.c:261 [inline] new_inode_pseudo+0x5f/0x1c0 fs/inode.c:1063 sock_alloc net/socket.c:631 [inline] __sock_create+0x129/0x940 net/socket.c:1514 sock_create net/socket.c:1606 [inline] __sys_socket_create net/socket.c:1643 [inline] __sys_socket+0xc4/0x190 net/socket.c:1671 __do_sys_socket net/socket.c:1684 [inline] __se_sys_socket net/socket.c:1682 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1682 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 Memory state around the buggy address: ffff8880247d8580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880247d8600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880247d8680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880247d8700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880247d8780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================