================================================================== BUG: KASAN: use-after-free in __tctx_task_work fs/io_uring.c:2217 [inline] BUG: KASAN: use-after-free in tctx_task_work+0x318/0x330 fs/io_uring.c:2230 Read of size 4 at addr ffff888023b7a3f0 by task syz-executor.3/16777 CPU: 1 PID: 16777 Comm: syz-executor.3 Not tainted 5.11.0-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+0xfa/0x151 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230 __kasan_report mm/kasan/report.c:396 [inline] kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413 __tctx_task_work fs/io_uring.c:2217 [inline] tctx_task_work+0x318/0x330 fs/io_uring.c:2230 task_work_run+0xdd/0x1a0 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xc61/0x2ae0 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x42c/0x2100 kernel/signal.c:2773 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+0x148/0x250 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:301 __do_fast_syscall_32+0x62/0x80 arch/x86/entry/common.c:142 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:164 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7fa4549 Code: Unable to access opcode bytes at RIP 0xf7fa451f. RSP: 002b:00000000f557d5fc EFLAGS: 00000296 ORIG_RAX: 00000000000001aa RAX: 0000000000000302 RBX: 0000000000000003 RCX: 0000000000000302 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 16762: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:401 [inline] ____kasan_kmalloc.constprop.0+0x82/0xa0 mm/kasan/common.c:429 kmalloc include/linux/slab.h:554 [inline] kzalloc include/linux/slab.h:684 [inline] io_ring_ctx_alloc fs/io_uring.c:1316 [inline] io_uring_create fs/io_uring.c:9745 [inline] io_uring_setup+0x35b/0x36f0 fs/io_uring.c:9876 do_syscall_32_irqs_on arch/x86/entry/common.c:77 [inline] __do_fast_syscall_32+0x56/0x80 arch/x86/entry/common.c:139 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:164 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c Freed by task 247: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:356 ____kasan_slab_free+0xe1/0x110 mm/kasan/common.c:362 kasan_slab_free include/linux/kasan.h:192 [inline] slab_free_hook mm/slub.c:1547 [inline] slab_free_freelist_hook+0x51/0x130 mm/slub.c:1580 slab_free mm/slub.c:3143 [inline] kfree+0xdb/0x3b0 mm/slub.c:4179 process_one_work+0x98d/0x1600 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:294 Last potentially related work creation: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_record_aux_stack+0xc5/0xf0 mm/kasan/generic.c:344 insert_work+0x48/0x370 kernel/workqueue.c:1331 __queue_work+0x5c1/0xf00 kernel/workqueue.c:1497 queue_work_on+0xae/0xc0 kernel/workqueue.c:1524 io_uring_release+0x3e/0x50 fs/io_uring.c:8895 __fput+0x288/0x920 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:140 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xc61/0x2ae0 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 get_signal+0x42c/0x2100 kernel/signal.c:2773 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+0x148/0x250 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:301 __do_fast_syscall_32+0x62/0x80 arch/x86/entry/common.c:142 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:164 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c The buggy address belongs to the object at ffff888023b7a000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 1008 bytes inside of 4096-byte region [ffff888023b7a000, ffff888023b7b000) The buggy address belongs to the page: page:00000000f2ccecc8 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x23b78 head:00000000f2ccecc8 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010c42140 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888023b7a280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888023b7a300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888023b7a380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888023b7a400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888023b7a480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================