================================================================== BUG: KASAN: slab-use-after-free in sysfs_remove_file_ns+0x63/0x70 fs/sysfs/file.c:510 Read of size 8 at addr ffff88800b68ec30 by task syz.2.2981/21612 CPU: 3 UID: 0 PID: 21612 Comm: syz.2.2981 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: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 do_devconfig_ioctl+0x555/0x710 drivers/comedi/comedi_fops.c:848 comedi_unlocked_ioctl+0x165d/0x2f00 drivers/comedi/comedi_fops.c:2178 comedi_compat_ioctl+0x1d0/0x990 drivers/comedi/comedi_fops.c:3249 __do_compat_sys_ioctl fs/ioctl.c:695 [inline] __se_compat_sys_ioctl fs/ioctl.c:638 [inline] __ia32_compat_sys_ioctl+0x242/0x370 fs/ioctl.c:638 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x300 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: 0023:0xf7f64579 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:00000000f4ff155c EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 0000000040946400 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 17964: 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:5627 [inline] __kmalloc_noprof+0x32f/0x880 mm/slub.c:5639 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_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x7c/0x300 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 17964: 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_mempool_poison_object+0xc5/0x1c0 mm/kasan/common.c:545 kasan_mempool_poison_object include/linux/kasan.h:362 [inline] io_alloc_cache_put io_uring/alloc_cache.h:23 [inline] io_rw_recycle io_uring/rw.c:158 [inline] io_readv_writev_cleanup+0x1fc/0x3a0 io_uring/rw.c:467 io_clean_op io_uring/io_uring.c:409 [inline] io_free_batch_list io_uring/io_uring.c:1531 [inline] __io_submit_flush_completions+0xe39/0x1980 io_uring/io_uring.c:1569 io_submit_flush_completions io_uring/io_uring.h:220 [inline] ctx_flush_and_put+0x9a/0x410 io_uring/io_uring.c:1123 io_handle_tw_list+0x3c1/0x500 io_uring/io_uring.c:1163 tctx_task_work_run+0xac/0x380 io_uring/io_uring.c:1216 tctx_task_work+0x7a/0xd0 io_uring/io_uring.c:1234 task_work_run+0x150/0x240 kernel/task_work.c:227 get_signal+0x1d0/0x26d0 kernel/signal.c:2807 arch_do_signal_or_restart+0x8f/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] __do_fast_syscall_32+0x240/0x300 arch/x86/entry/syscall_32.c:309 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 ffff88800b68ec00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff88800b68ec00, ffff88800b68ed00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88800b68e600 pfn:0xb68e 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 ffff88801b442b40 ffffea00004b9210 ffffea00004d1090 raw: ffff88800b68e600 000000000010000f 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801b442b40 ffffea00004b9210 ffffea00004d1090 head: ffff88800b68e600 000000000010000f 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea00002da381 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 6130, tgid 6130 (syz.2.14), ts 62715339996, free_ts 62480424162 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_slab_page mm/slub.c:3041 [inline] allocate_slab mm/slub.c:3212 [inline] new_slab+0xa5/0x360 mm/slub.c:3266 ___slab_alloc+0xdc4/0x1ae0 mm/slub.c:4636 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4755 __slab_alloc_node mm/slub.c:4831 [inline] slab_alloc_node mm/slub.c:5253 [inline] __do_kmalloc_node mm/slub.c:5626 [inline] __kmalloc_node_noprof+0x4dd/0x8a0 mm/slub.c:5633 kmalloc_array_node_noprof include/linux/slab.h:1075 [inline] alloc_slab_obj_exts+0x3a/0xd0 mm/slub.c:2123 __memcg_slab_post_alloc_hook+0x251/0x940 mm/memcontrol.c:3173 memcg_slab_post_alloc_hook mm/slub.c:2322 [inline] slab_post_alloc_hook mm/slub.c:4966 [inline] slab_alloc_node mm/slub.c:5265 [inline] kmem_cache_alloc_noprof+0x550/0x6e0 mm/slub.c:5272 vm_area_dup+0x27/0x8d0 mm/vma_init.c:123 __split_vma+0x18e/0x1070 mm/vma.c:515 split_vma mm/vma.c:598 [inline] vma_modify+0xee1/0x2030 mm/vma.c:1631 vma_modify_flags+0x212/0x2d0 mm/vma.c:1649 mprotect_fixup+0x1df/0xb40 mm/mprotect.c:816 do_mprotect_pkey+0x9bc/0xd40 mm/mprotect.c:990 page last free pid 10 tgid 10 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 vfree+0x1fd/0xb50 mm/vmalloc.c:3440 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:3359 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff88800b68eb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88800b68eb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88800b68ec00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88800b68ec80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88800b68ed00: 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