syzbot

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BUG: KASAN: slab-use-after-free in task_pgrp include/linux/sched/signal.h:689 [inline]
BUG: KASAN: slab-use-after-free in kill_orphaned_pgrp+0x41/0x560 kernel/exit.c:379
Read of size 8 at addr ffff888021126308 by task vhost-8279/8281

CPU: 0 PID: 8281 Comm: vhost-8279 Not tainted 6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 task_pgrp include/linux/sched/signal.h:689 [inline]
 kill_orphaned_pgrp+0x41/0x560 kernel/exit.c:379
 exit_notify kernel/exit.c:739 [inline]
 do_exit+0x1673/0x27e0 kernel/exit.c:898
 vhost_task_fn+0x2ff/0x320 kernel/vhost_task.c:61
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Allocated by task 7920:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3798 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 kmem_cache_alloc_node+0x194/0x380 mm/slub.c:3888
 alloc_task_struct_node kernel/fork.c:176 [inline]
 dup_task_struct+0x57/0x7d0 kernel/fork.c:1107
 copy_process+0x5d1/0x3df0 kernel/fork.c:2220
 kernel_clone+0x226/0x8f0 kernel/fork.c:2797
 __do_sys_clone kernel/fork.c:2940 [inline]
 __se_sys_clone kernel/fork.c:2924 [inline]
 __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2924
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 8291:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
 poison_slab_object+0xa6/0xe0 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2106 [inline]
 slab_free mm/slub.c:4280 [inline]
 kmem_cache_free+0x10b/0x2c0 mm/slub.c:4344
 put_task_struct include/linux/sched/task.h:138 [inline]
 delayed_put_task_struct+0x125/0x2f0 kernel/exit.c:229
 rcu_do_batch kernel/rcu/tree.c:2196 [inline]
 rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2471
 __do_softirq+0x2c6/0x980 kernel/softirq.c:554

Last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
 __call_rcu_common kernel/rcu/tree.c:2734 [inline]
 call_rcu+0x167/0xa70 kernel/rcu/tree.c:2838
 release_task+0x16d2/0x1810
 de_thread fs/exec.c:1172 [inline]
 begin_new_exec+0xfde/0x1ce0 fs/exec.c:1278
 load_elf_binary+0x961/0x2590 fs/binfmt_elf.c:996
 search_binary_handler fs/exec.c:1778 [inline]
 exec_binprm fs/exec.c:1820 [inline]
 bprm_execve+0xaf8/0x17c0 fs/exec.c:1872
 do_execveat_common+0x553/0x700 fs/exec.c:1979
 do_execveat fs/exec.c:2064 [inline]
 __do_sys_execveat fs/exec.c:2138 [inline]
 __se_sys_execveat fs/exec.c:2132 [inline]
 __x64_sys_execveat+0xc4/0xe0 fs/exec.c:2132
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888021125a00
 which belongs to the cache task_struct of size 7424
The buggy address is located 2312 bytes inside of
 freed 7424-byte region [ffff888021125a00, ffff888021127700)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21120
head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88802d5fce81
flags: 0xfff80000000840(slab|head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000840 ffff8880162a6500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000001ffffffff ffff88802d5fce81
head: 00fff80000000840 ffff8880162a6500 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 00000001ffffffff ffff88802d5fce81
head: 00fff80000000003 ffffea0000844801 ffffea0000844848 00000000ffffffff
head: 0000000800000000 0000000000000000 00000000ffffffff 0000000000000000
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 10, tgid 443580159 (kworker/u8:0), ts 10, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
 prep_new_page mm/page_alloc.c:1541 [inline]
 get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
 __alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page+0x5f/0x160 mm/slub.c:2175
 allocate_slab mm/slub.c:2338 [inline]
 new_slab+0x84/0x2f0 mm/slub.c:2391
 ___slab_alloc+0xc73/0x1260 mm/slub.c:3525
 __slab_alloc mm/slub.c:3610 [inline]
 __slab_alloc_node mm/slub.c:3663 [inline]
 slab_alloc_node mm/slub.c:3835 [inline]
 kmem_cache_alloc_node+0x24a/0x380 mm/slub.c:3888
 alloc_task_struct_node kernel/fork.c:176 [inline]
 dup_task_struct+0x57/0x7d0 kernel/fork.c:1107
 copy_process+0x5d1/0x3df0 kernel/fork.c:2220
 kernel_clone+0x226/0x8f0 kernel/fork.c:2797
 user_mode_thread+0x132/0x1a0 kernel/fork.c:2875
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:172
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888021126200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888021126280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888021126300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888021126380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888021126400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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