R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 comedi comedi3: c6xdigio: I/O port conflict (0x4f2b,3) ================================================================== BUG: KASAN: slab-use-after-free in sysfs_remove_file_ns+0x63/0x70 fs/sysfs/file.c:522 Read of size 8 at addr ffff88804cd3b430 by task syz.2.1803/12405 CPU: 1 UID: 0 PID: 12405 Comm: syz.2.1803 Not tainted syzkaller #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/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:522 sysfs_remove_file include/linux/sysfs.h:777 [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+0x12c/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:1010 do_devconfig_ioctl+0x1b1/0x710 drivers/comedi/comedi_fops.c:872 comedi_unlocked_ioctl+0x165d/0x2f00 drivers/comedi/comedi_fops.c:2173 comedi_compat_ioctl+0x1d0/0x990 drivers/comedi/comedi_fops.c:3244 __do_compat_sys_ioctl fs/ioctl.c:696 [inline] __se_compat_sys_ioctl fs/ioctl.c:639 [inline] __ia32_compat_sys_ioctl+0x23f/0x370 fs/ioctl.c:639 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf70fe579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f54ee55c EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000040946400 RDX: 00000000800000c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 11733: 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:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] set_mm_walk+0x1f8/0x270 mm/vmscan.c:3852 try_to_inc_max_seq+0xea/0xfa0 mm/vmscan.c:4077 get_nr_to_scan mm/vmscan.c:4860 [inline] try_to_shrink_lruvec+0x735/0x9b0 mm/vmscan.c:4903 shrink_one+0x3e3/0x7a0 mm/vmscan.c:4952 shrink_many mm/vmscan.c:5015 [inline] lru_gen_shrink_node mm/vmscan.c:5093 [inline] shrink_node+0x26b5/0x3d50 mm/vmscan.c:6078 shrink_zones mm/vmscan.c:6336 [inline] do_try_to_free_pages+0x362/0x1920 mm/vmscan.c:6398 try_to_free_pages+0x2a1/0x690 mm/vmscan.c:6644 __perform_reclaim mm/page_alloc.c:4310 [inline] __alloc_pages_direct_reclaim mm/page_alloc.c:4332 [inline] __alloc_pages_slowpath mm/page_alloc.c:4781 [inline] __alloc_frozen_pages_noprof+0x9fc/0x23f0 mm/page_alloc.c:5161 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline] alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2507 vm_area_alloc_pages mm/vmalloc.c:3642 [inline] __vmalloc_area_node mm/vmalloc.c:3720 [inline] __vmalloc_node_range_noprof+0x72f/0x14b0 mm/vmalloc.c:3893 vmalloc_user_noprof+0x9e/0xe0 mm/vmalloc.c:4046 vb2_vmalloc_alloc+0x135/0x3f0 drivers/media/common/videobuf2/videobuf2-vmalloc.c:47 __vb2_buf_mem_alloc drivers/media/common/videobuf2/videobuf2-core.c:242 [inline] __vb2_queue_alloc+0x8c9/0x1280 drivers/media/common/videobuf2/videobuf2-core.c:523 vb2_core_reqbufs+0xa90/0xfe0 drivers/media/common/videobuf2/videobuf2-core.c:964 vb2_reqbufs+0x1a3/0x1f0 drivers/media/common/videobuf2/videobuf2-v4l2.c:715 v4l2_m2m_reqbufs drivers/media/v4l2-core/v4l2-mem2mem.c:582 [inline] v4l2_m2m_ioctl_reqbufs+0xdc/0x1e0 drivers/media/v4l2-core/v4l2-mem2mem.c:1376 v4l_reqbufs+0x152/0x1e0 drivers/media/v4l2-core/v4l2-ioctl.c:2170 __video_do_ioctl+0xb40/0xfc0 drivers/media/v4l2-core/v4l2-ioctl.c:3137 video_usercopy+0x47c/0x1440 drivers/media/v4l2-core/v4l2-ioctl.c:3479 v4l2_ioctl+0x1bd/0x250 drivers/media/v4l2-core/v4l2-dev.c:366 v4l2_compat_ioctl32+0x217/0x2c0 drivers/media/v4l2-core/v4l2-compat-ioctl32.c:1200 __do_compat_sys_ioctl fs/ioctl.c:696 [inline] __se_compat_sys_ioctl fs/ioctl.c:639 [inline] __ia32_compat_sys_ioctl+0x23f/0x370 fs/ioctl.c:639 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 11733: 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:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4879 clear_mm_walk+0x162/0x1a0 mm/vmscan.c:3870 lru_gen_shrink_node mm/vmscan.c:5098 [inline] shrink_node+0x309f/0x3d50 mm/vmscan.c:6078 shrink_zones mm/vmscan.c:6336 [inline] do_try_to_free_pages+0x362/0x1920 mm/vmscan.c:6398 try_to_free_pages+0x2a1/0x690 mm/vmscan.c:6644 __perform_reclaim mm/page_alloc.c:4310 [inline] __alloc_pages_direct_reclaim mm/page_alloc.c:4332 [inline] __alloc_pages_slowpath mm/page_alloc.c:4781 [inline] __alloc_frozen_pages_noprof+0x9fc/0x23f0 mm/page_alloc.c:5161 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline] alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2507 vm_area_alloc_pages mm/vmalloc.c:3642 [inline] __vmalloc_area_node mm/vmalloc.c:3720 [inline] __vmalloc_node_range_noprof+0x72f/0x14b0 mm/vmalloc.c:3893 vmalloc_user_noprof+0x9e/0xe0 mm/vmalloc.c:4046 vb2_vmalloc_alloc+0x135/0x3f0 drivers/media/common/videobuf2/videobuf2-vmalloc.c:47 __vb2_buf_mem_alloc drivers/media/common/videobuf2/videobuf2-core.c:242 [inline] __vb2_queue_alloc+0x8c9/0x1280 drivers/media/common/videobuf2/videobuf2-core.c:523 vb2_core_reqbufs+0xa90/0xfe0 drivers/media/common/videobuf2/videobuf2-core.c:964 vb2_reqbufs+0x1a3/0x1f0 drivers/media/common/videobuf2/videobuf2-v4l2.c:715 v4l2_m2m_reqbufs drivers/media/v4l2-core/v4l2-mem2mem.c:582 [inline] v4l2_m2m_ioctl_reqbufs+0xdc/0x1e0 drivers/media/v4l2-core/v4l2-mem2mem.c:1376 v4l_reqbufs+0x152/0x1e0 drivers/media/v4l2-core/v4l2-ioctl.c:2170 __video_do_ioctl+0xb40/0xfc0 drivers/media/v4l2-core/v4l2-ioctl.c:3137 video_usercopy+0x47c/0x1440 drivers/media/v4l2-core/v4l2-ioctl.c:3479 v4l2_ioctl+0x1bd/0x250 drivers/media/v4l2-core/v4l2-dev.c:366 v4l2_compat_ioctl32+0x217/0x2c0 drivers/media/v4l2-core/v4l2-compat-ioctl32.c:1200 __do_compat_sys_ioctl fs/ioctl.c:696 [inline] __se_compat_sys_ioctl fs/ioctl.c:639 [inline] __ia32_compat_sys_ioctl+0x23f/0x370 fs/ioctl.c:639 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e The buggy address belongs to the object at ffff88804cd3b400 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff88804cd3b400, ffff88804cd3b500) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88804cd3b200 pfn:0x4cd3a head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x4fff00000000240(workingset|head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000240 ffff88801b842b40 ffffea0001b3b590 ffffea0001468810 raw: ffff88804cd3b200 0000000000100008 00000000f5000000 0000000000000000 head: 04fff00000000240 ffff88801b842b40 ffffea0001b3b590 ffffea0001468810 head: ffff88804cd3b200 0000000000100008 00000000f5000000 0000000000000000 head: 04fff00000000001 ffffea0001334e81 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 6235, tgid 6230 (syz.3.41), ts 56812051274, free_ts 51586752014 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x247/0x330 mm/slub.c:2709 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] __do_kmalloc_node mm/slub.c:4364 [inline] __kmalloc_noprof+0x2f2/0x510 mm/slub.c:4377 kmalloc_noprof include/linux/slab.h:909 [inline] kmalloc_array_noprof include/linux/slab.h:948 [inline] iter_file_splice_write+0x1cc/0x12e0 fs/splice.c:679 backing_file_splice_write+0x27c/0x890 fs/backing-file.c:315 ovl_splice_write+0x38d/0x6c0 fs/overlayfs/file.c:440 do_splice_from fs/splice.c:938 [inline] direct_splice_actor+0x192/0x6c0 fs/splice.c:1161 splice_direct_to_actor+0x345/0xa30 fs/splice.c:1105 do_splice_direct_actor fs/splice.c:1204 [inline] do_splice_direct+0x174/0x240 fs/splice.c:1230 do_sendfile+0xb06/0xe50 fs/read_write.c:1370 __do_compat_sys_sendfile fs/read_write.c:1446 [inline] __se_compat_sys_sendfile fs/read_write.c:1435 [inline] __ia32_compat_sys_sendfile+0x162/0x220 fs/read_write.c:1435 page last free pid 33 tgid 33 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0x799/0x1530 kernel/rcu/tree.c:2861 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579 run_ksoftirqd kernel/softirq.c:968 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960 smpboot_thread_fn+0x3f7/0xae0 kernel/smpboot.c:160 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 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: ffff88804cd3b300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88804cd3b380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88804cd3b400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804cd3b480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804cd3b500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi