================================================================== BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:938 [inline] BUG: KASAN: use-after-free in __mutex_lock+0x102f/0x1110 kernel/locking/mutex.c:1103 Read of size 8 at addr ffff888075a3d3e0 by task syz-executor.2/11651 CPU: 0 PID: 11651 Comm: syz-executor.2 Not tainted 5.10.0-next-20201221-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:235 __kasan_report mm/kasan/report.c:401 [inline] kasan_report.cold+0x79/0xd5 mm/kasan/report.c:418 __mutex_lock_common kernel/locking/mutex.c:938 [inline] __mutex_lock+0x102f/0x1110 kernel/locking/mutex.c:1103 io_ring_ctx_wait_and_kill+0x27/0x560 fs/io_uring.c:8644 io_uring_release+0x3e/0x50 fs/io_uring.c:8685 __fput+0x283/0x920 fs/file_table.c:280 task_work_run+0xdd/0x190 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xb89/0x2a00 kernel/exit.c:823 do_group_exit+0x125/0x310 kernel/exit.c:920 get_signal+0x3e9/0x2160 kernel/signal.c:2770 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811 handle_signal_work kernel/entry/common.c:147 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x124/0x200 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45e149 Code: Unable to access opcode bytes at RIP 0x45e11f. RSP: 002b:00007f3a42aa0be8 EFLAGS: 00000206 ORIG_RAX: 00000000000001a9 RAX: fffffffffffffff4 RBX: 0000000020000080 RCX: 000000000045e149 RDX: 00000000206d4000 RSI: 0000000020000080 RDI: 0000000000000087 RBP: 000000000119c080 R08: 0000000020000040 R09: 0000000020000040 R10: 0000000020000000 R11: 0000000000000206 R12: 00000000206d4000 R13: 0000000020ee7000 R14: 0000000020000040 R15: 0000000020000000 Allocated by task 11651: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:43 kasan_set_track mm/kasan/common.c:51 [inline] set_alloc_info mm/kasan/common.c:409 [inline] ____kasan_kmalloc mm/kasan/common.c:440 [inline] ____kasan_kmalloc.constprop.0+0xa0/0xd0 mm/kasan/common.c:412 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:682 [inline] io_ring_ctx_alloc fs/io_uring.c:1268 [inline] io_uring_create fs/io_uring.c:9481 [inline] io_uring_setup+0x51a/0x39c0 fs/io_uring.c:9614 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 54: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:43 kasan_set_track+0x1c/0x30 mm/kasan/common.c:51 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free.part.0+0xe1/0x110 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:188 [inline] slab_free_hook mm/slub.c:1548 [inline] slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1586 slab_free mm/slub.c:3157 [inline] kfree+0xdb/0x3c0 mm/slub.c:4156 process_one_work+0x98d/0x1630 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:43 kasan_record_aux_stack+0xdc/0x100 mm/kasan/generic.c:348 insert_work+0x48/0x370 kernel/workqueue.c:1331 __queue_work+0x5c1/0xfb0 kernel/workqueue.c:1497 queue_work_on+0xc7/0xd0 kernel/workqueue.c:1524 io_uring_create fs/io_uring.c:9587 [inline] io_uring_setup+0x1350/0x39c0 fs/io_uring.c:9614 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Second to last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:43 kasan_record_aux_stack+0xdc/0x100 mm/kasan/generic.c:348 insert_work+0x48/0x370 kernel/workqueue.c:1331 __queue_work+0x5c1/0xfb0 kernel/workqueue.c:1497 queue_work_on+0xc7/0xd0 kernel/workqueue.c:1524 kref_put include/linux/kref.h:65 [inline] tty_kref_put drivers/tty/tty_io.c:1493 [inline] release_tty+0x4e9/0x610 drivers/tty/tty_io.c:1530 tty_release_struct+0xb4/0xe0 drivers/tty/tty_io.c:1629 tty_release+0xc70/0x1210 drivers/tty/tty_io.c:1789 __fput+0x283/0x920 fs/file_table.c:280 task_work_run+0xdd/0x190 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xb89/0x2a00 kernel/exit.c:823 do_group_exit+0x125/0x310 kernel/exit.c:920 get_signal+0x3e9/0x2160 kernel/signal.c:2770 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811 handle_signal_work kernel/entry/common.c:147 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x124/0x200 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff888075a3d000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 992 bytes inside of 2048-byte region [ffff888075a3d000, ffff888075a3d800) The buggy address belongs to the page: page:0000000088c049b9 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x75a38 head:0000000088c049b9 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010842000 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888075a3d280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888075a3d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888075a3d380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888075a3d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888075a3d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================