================================================================== BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 Read of size 1 at addr ffff888025aafcb0 by task syz.0.954/9182 CPU: 2 UID: 0 PID: 9182 Comm: syz.0.954 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 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/0x610 mm/kasan/report.c:480 kasan_report+0xe0/0x110 mm/kasan/report.c:593 __kasan_check_byte+0x36/0x50 mm/kasan/common.c:557 kasan_check_byte include/linux/kasan.h:399 [inline] lock_acquire kernel/locking/lockdep.c:5845 [inline] lock_acquire+0xfc/0x350 kernel/locking/lockdep.c:5828 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 remove_wait_queue+0x25/0x180 kernel/sched/wait.c:54 free_poll_entry fs/select.c:132 [inline] poll_freewait+0xd5/0x250 fs/select.c:141 do_select+0xe52/0x17e0 fs/select.c:608 core_sys_select+0x453/0xc10 fs/select.c:677 do_pselect.constprop.0+0x19f/0x1e0 fs/select.c:759 __do_sys_pselect6 fs/select.c:802 [inline] __se_sys_pselect6 fs/select.c:793 [inline] __x64_sys_pselect6+0x182/0x240 fs/select.c:793 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb58cb8e929 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:00007fb58da13038 EFLAGS: 00000246 ORIG_RAX: 000000000000010e RAX: ffffffffffffffda RBX: 00007fb58cdb5fa0 RCX: 00007fb58cb8e929 RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000000000000040 RBP: 00007fb58cc10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 00002000000002c0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb58cdb5fa0 R15: 00007ffef9110ec8 Allocated by task 1: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] __comedi_device_postconfig_async drivers/comedi/drivers.c:664 [inline] __comedi_device_postconfig drivers/comedi/drivers.c:721 [inline] comedi_device_postconfig+0x2cb/0xc80 drivers/comedi/drivers.c:756 comedi_auto_config+0x1a3/0x440 drivers/comedi/drivers.c:1069 comedi_test_init+0xd0/0x160 drivers/comedi/drivers/comedi_test.c:836 do_one_initcall+0x120/0x6e0 init/main.c:1274 do_initcall_level init/main.c:1336 [inline] do_initcalls init/main.c:1352 [inline] do_basic_setup init/main.c:1371 [inline] kernel_init_freeable+0x5c2/0x900 init/main.c:1584 kernel_init+0x1c/0x2b0 init/main.c:1474 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 9186: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 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+0x2b4/0x4d0 mm/slub.c:4842 comedi_device_detach_cleanup drivers/comedi/drivers.c:171 [inline] comedi_device_detach+0x2a4/0x9e0 drivers/comedi/drivers.c:208 do_devconfig_ioctl+0x46c/0x580 drivers/comedi/comedi_fops.c:833 comedi_unlocked_ioctl+0x15bb/0x2e90 drivers/comedi/comedi_fops.c:2136 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888025aafc00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 176 bytes inside of freed 256-byte region [ffff888025aafc00, ffff888025aafd00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x25aae head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b842b40 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b842b40 0000000000000000 dead000000000001 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea000096ab81 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 36, tgid 36 (kdevtmpfs), ts 7536622599, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704 prep_new_page mm/page_alloc.c:1712 [inline] get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419 alloc_slab_page mm/slub.c:2451 [inline] allocate_slab mm/slub.c:2619 [inline] new_slab+0x23b/0x330 mm/slub.c:2673 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949 __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_noprof+0x2f2/0x510 mm/slub.c:4340 kmalloc_noprof include/linux/slab.h:909 [inline] kmalloc_array_noprof include/linux/slab.h:948 [inline] security_inode_init_security+0x13f/0x390 security/security.c:1829 shmem_mknod+0x22e/0x450 mm/shmem.c:3851 vfs_mknod+0x5da/0x8e0 fs/namei.c:4244 handle_create drivers/base/devtmpfs.c:233 [inline] handle drivers/base/devtmpfs.c:389 [inline] devtmpfs_work_loop+0x1b0/0xd90 drivers/base/devtmpfs.c:404 devtmpfsd+0x4c/0x50 drivers/base/devtmpfs.c:446 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page_owner free stack trace missing Memory state around the buggy address: ffff888025aafb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888025aafc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888025aafc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888025aafd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888025aafd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================