syzbot

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BUG: KASAN: slab-use-after-free in uart_write_room+0x85e/0x940 drivers/tty/serial/serial_core.c:643
Read of size 8 at addr ffff88805531d5f8 by task aoe_tx0/1424

CPU: 0 UID: 0 PID: 1424 Comm: aoe_tx0 Not tainted 6.15.0-syzkaller-13743-g8630c59e9936 #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:
 <TASK>
 __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:408 [inline]
 print_report+0xcd/0x680 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 uart_write_room+0x85e/0x940 drivers/tty/serial/serial_core.c:643
 tty_write_room+0x63/0x90 drivers/tty/tty_ioctl.c:69
 handle_tx+0x14f/0x630 drivers/net/caif/caif_serial.c:212
 __netdev_start_xmit include/linux/netdevice.h:5215 [inline]
 netdev_start_xmit include/linux/netdevice.h:5224 [inline]
 xmit_one net/core/dev.c:3830 [inline]
 dev_hard_start_xmit+0x97/0x740 net/core/dev.c:3846
 __dev_queue_xmit+0x7eb/0x43e0 net/core/dev.c:4713
 dev_queue_xmit include/linux/netdevice.h:3355 [inline]
 tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62
 kthread+0x1e4/0x3e0 drivers/block/aoe/aoecmd.c:1237
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6039:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 alloc_tty_struct+0x96/0x8c0 drivers/tty/tty_io.c:3102
 tty_init_dev.part.0+0x1e/0x500 drivers/tty/tty_io.c:1400
 tty_init_dev include/linux/err.h:70 [inline]
 tty_open_by_driver drivers/tty/tty_io.c:2073 [inline]
 tty_open+0xa50/0xf90 drivers/tty/tty_io.c:2120
 chrdev_open+0x234/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x744/0x1c10 fs/open.c:964
 vfs_open+0x82/0x3f0 fs/open.c:1094
 do_open fs/namei.c:3887 [inline]
 path_openat+0x1de4/0x2cb0 fs/namei.c:4046
 do_filp_open+0x20b/0x470 fs/namei.c:4073
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6007:
 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:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4842
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548
 insert_work+0x36/0x230 kernel/workqueue.c:2183
 __queue_work+0x97e/0x10f0 kernel/workqueue.c:2341
 queue_work_on+0x1a4/0x1f0 kernel/workqueue.c:2392
 kref_put include/linux/kref.h:65 [inline]
 tty_kref_put drivers/tty/tty_io.c:1557 [inline]
 tty_kref_put drivers/tty/tty_io.c:1554 [inline]
 release_tty+0x4de/0x5d0 drivers/tty/tty_io.c:1593
 tty_release_struct+0xb7/0xe0 drivers/tty/tty_io.c:1692
 tty_release+0xe2d/0x1430 drivers/tty/tty_io.c:1852
 __fput+0x402/0xb70 fs/file_table.c:465
 task_work_run+0x14d/0x240 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x864/0x2bd0 kernel/exit.c:955
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1104
 get_signal+0x2673/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88805531d000
 which belongs to the cache kmalloc-cg-2k of size 2048
The buggy address is located 1528 bytes inside of
 freed 2048-byte region [ffff88805531d000, ffff88805531d800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888055318000 pfn:0x55318
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888033152101
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b84c140 dead000000000100 dead000000000122
raw: ffff888055318000 0000000080080006 00000000f5000000 ffff888033152101
head: 00fff00000000040 ffff88801b84c140 dead000000000100 dead000000000122
head: ffff888055318000 0000000080080006 00000000f5000000 ffff888033152101
head: 00fff00000000003 ffffea000154c601 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5938, tgid 5938 (syz-executor), ts 48083571493, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab mm/slub.c:2619 [inline]
 new_slab+0x23b/0x330 mm/slub.c:2673
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kvmalloc_node_noprof+0x3b1/0x620 mm/slub.c:5015
 kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline]
 alloc_fdtable+0xee/0x2b0 fs/file.c:204
 dup_fd+0x83b/0xb90 fs/file.c:405
 copy_files kernel/fork.c:1583 [inline]
 copy_process+0x230c/0x76a0 kernel/fork.c:2157
 kernel_clone+0xfc/0x960 kernel/fork.c:2599
 __do_sys_clone+0xce/0x120 kernel/fork.c:2742
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88805531d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805531d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805531d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff88805531d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805531d680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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