================================================================== BUG: KASAN: slab-use-after-free in sysfs_remove_file_ns+0x63/0x70 fs/sysfs/file.c:510 Read of size 8 at addr ffff88802f0ef230 by task syz.1.3410/26591 CPU: 1 UID: 0 PID: 26591 Comm: syz.1.3410 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP 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 comedi_device_detach+0x67/0xb0 drivers/comedi/drivers.c:215 comedi_device_attach+0x43d/0x900 drivers/comedi/drivers.c:1011 do_devconfig_ioctl+0x1b1/0x710 drivers/comedi/comedi_fops.c:872 comedi_unlocked_ioctl+0x165d/0x2ee0 drivers/comedi/comedi_fops.c:2178 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa25098f7c9 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:00007fa24ebf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa250be5fa0 RCX: 00007fa25098f7c9 RDX: 0000200000000340 RSI: 0000000040946400 RDI: 000000000000000a RBP: 00007fa250a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa250be6038 R14: 00007fa250be5fa0 R15: 00007ffc82f601d8 Allocated by task 26004: 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:5652 [inline] __kvmalloc_node_noprof+0x39e/0xa50 mm/slub.c:7128 kvmalloc_array_node_noprof include/linux/slab.h:1122 [inline] io_alloc_cache_init+0x38/0x170 io_uring/alloc_cache.c:25 io_ring_ctx_alloc io_uring/io_uring.c:326 [inline] io_uring_create io_uring/io_uring.c:3583 [inline] io_uring_setup+0x5da/0x1ff0 io_uring/io_uring.c:3715 __do_sys_io_uring_setup io_uring/io_uring.c:3749 [inline] __se_sys_io_uring_setup io_uring/io_uring.c:3740 [inline] __x64_sys_io_uring_setup+0xc2/0x170 io_uring/io_uring.c:3740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 7203: 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_slab_free+0x5f/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6663 [inline] kfree+0x2f8/0x6e0 mm/slub.c:6871 io_alloc_cache_free+0x1eb/0x2e0 io_uring/alloc_cache.c:16 io_free_alloc_caches io_uring/io_uring.c:280 [inline] io_ring_ctx_free io_uring/io_uring.c:2848 [inline] io_ring_exit_work+0x7e0/0x1130 io_uring/io_uring.c:3073 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 The buggy address belongs to the object at ffff88802f0ef200 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 48 bytes inside of freed 256-byte region [ffff88802f0ef200, ffff88802f0ef300) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802f0eea00 pfn:0x2f0ee 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 ffffea0000bdcf10 ffffea0000f15290 raw: ffff88802f0eea00 0000000000100006 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801b442b40 ffffea0000bdcf10 ffffea0000f15290 head: ffff88802f0eea00 0000000000100006 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000bc3b81 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 0x1d2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 7461, tgid 7461 (syz-executor), ts 91816849814, free_ts 83397389094 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1845 prep_new_page mm/page_alloc.c:1853 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3879 __alloc_frozen_pages_noprof+0x25f/0x2440 mm/page_alloc.c:5183 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0x2c3/0x430 mm/slub.c:3302 ___slab_alloc+0xe18/0x1c90 mm/slub.c:4651 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4774 __slab_alloc_node mm/slub.c:4850 [inline] slab_alloc_node mm/slub.c:5246 [inline] __do_kmalloc_node mm/slub.c:5651 [inline] __kmalloc_noprof+0x501/0x8f0 mm/slub.c:5664 kmalloc_noprof include/linux/slab.h:961 [inline] kmalloc_array_noprof include/linux/slab.h:1003 [inline] security_inode_init_security+0x113/0x370 security/security.c:1321 shmem_symlink+0x135/0x9f0 mm/shmem.c:4101 vfs_symlink fs/namei.c:5514 [inline] vfs_symlink+0x4b5/0x800 fs/namei.c:5493 do_symlinkat+0x353/0x4b0 fs/namei.c:5541 __do_sys_symlinkat fs/namei.c:5562 [inline] __se_sys_symlinkat fs/namei.c:5559 [inline] __x64_sys_symlinkat+0x93/0xc0 fs/namei.c:5559 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 6793 tgid 6793 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:2901 discard_slab mm/slub.c:3346 [inline] __put_partials+0x130/0x170 mm/slub.c:3886 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4c/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4948 [inline] slab_alloc_node mm/slub.c:5258 [inline] kmem_cache_alloc_noprof+0x250/0x760 mm/slub.c:5265 getname_flags.part.0+0x4c/0x550 fs/namei.c:146 getname_flags+0x93/0xf0 include/linux/audit.h:345 user_path_at+0x24/0x60 fs/namei.c:3566 do_utimes_path fs/utimes.c:96 [inline] do_utimes+0x102/0x2a0 fs/utimes.c:141 __do_sys_utimensat fs/utimes.c:160 [inline] __se_sys_utimensat fs/utimes.c:144 [inline] __x64_sys_utimensat+0x1c6/0x290 fs/utimes.c:144 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802f0ef100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802f0ef180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802f0ef200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802f0ef280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802f0ef300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================