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BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x4e/0x130 lib/list_debug.c:29
Read of size 8 at addr ffff88802b131400 by task syz.6.4322/29386

CPU: 0 UID: 0 PID: 29386 Comm: syz.6.4322 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __list_add_valid_or_report+0x4e/0x130 lib/list_debug.c:29
 __list_add_valid include/linux/list.h:96 [inline]
 __list_add include/linux/list.h:158 [inline]
 list_add include/linux/list.h:177 [inline]
 clone_mnt+0x447/0x9a0 fs/namespace.c:1275
 copy_tree+0xde/0x930 fs/namespace.c:2159
 get_detached_copy fs/namespace.c:3030 [inline]
 open_detached_copy+0x229/0x540 fs/namespace.c:3046
 vfs_open_tree+0x361/0x3d0 fs/namespace.c:3222
 __do_sys_open_tree fs/namespace.c:3229 [inline]
 __se_sys_open_tree fs/namespace.c:3227 [inline]
 __x64_sys_open_tree+0x96/0x110 fs/namespace.c:3227
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f016019bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0161131028 EFLAGS: 00000246 ORIG_RAX: 00000000000001ac
RAX: ffffffffffffffda RBX: 00007f0160415fa0 RCX: 00007f016019bf79
RDX: 0000000000089901 RSI: 0000200000000640 RDI: ffffffffffffff9c
RBP: 00007f01602327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0160416038 R14: 00007f0160415fa0 R15: 00007fffb367f658
 </TASK>

Allocated by task 29338:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4837
 mt_alloc_one lib/maple_tree.c:174 [inline]
 mas_alloc_nodes+0x291/0x350 lib/maple_tree.c:1110
 mas_preallocate+0x2d6/0x640 lib/maple_tree.c:5194
 vma_iter_prealloc mm/vma.h:568 [inline]
 vma_link+0x123/0x470 mm/vma.c:1829
 insert_vm_struct+0x199/0x260 mm/vma.c:3295
 create_init_stack_vma+0x304/0x670 mm/vma_exec.c:146
 bprm_mm_init fs/exec.c:274 [inline]
 alloc_bprm+0x495/0x5c0 fs/exec.c:1457
 class_bprm_constructor fs/exec.c:1466 [inline]
 do_execveat_common+0x175/0x690 fs/exec.c:1799
 __do_sys_execve fs/exec.c:1930 [inline]
 __se_sys_execve fs/exec.c:1924 [inline]
 __x64_sys_execve+0x97/0xc0 fs/exec.c:1924
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 7434:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 __rcu_free_sheaf_prepare+0x129/0x290 mm/slub.c:2917
 rcu_free_sheaf+0x31/0x200 mm/slub.c:5770
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x870 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:727
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:743
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

The buggy address belongs to the object at ffff88802b131400
 which belongs to the cache maple_node of size 256
The buggy address is located 0 bytes inside of
 freed 256-byte region [ffff88802b131400, ffff88802b131500)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b130
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813ff39c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ff39c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0000ac4c01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 29267, tgid 29267 (syz.6.4310), ts 947263293095, free_ts 947195128147
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3255 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3444
 new_slab mm/slub.c:3502 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 __prefill_sheaf_pfmemalloc mm/slub.c:4895 [inline]
 kmem_cache_prefill_sheaf+0x2d4/0x530 mm/slub.c:4984
 mt_get_sheaf lib/maple_tree.c:189 [inline]
 mas_alloc_nodes+0x1c2/0x350 lib/maple_tree.c:1140
 mas_preallocate+0x2d6/0x640 lib/maple_tree.c:5194
 vma_iter_prealloc mm/vma.h:568 [inline]
 __split_vma+0x318/0xa40 mm/vma.c:526
 split_vma mm/vma.c:596 [inline]
 vma_modify+0x91b/0x2060 mm/vma.c:1672
 vma_modify_flags+0x24b/0x330 mm/vma.c:1700
 mprotect_fixup+0x47a/0xa80 mm/mprotect.c:756
 do_mprotect_pkey+0x8ab/0xcd0 mm/mprotect.c:930
 __do_sys_mprotect mm/mprotect.c:951 [inline]
 __se_sys_mprotect mm/mprotect.c:948 [inline]
 __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:948
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 29258 tgid 29258 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 mm_free_pgd kernel/fork.c:585 [inline]
 __mmdrop+0xb5/0x750 kernel/fork.c:727
 exit_mm+0x168/0x220 kernel/exit.c:581
 do_exit+0x62e/0x2320 kernel/exit.c:959
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112
 __do_sys_exit_group kernel/exit.c:1123 [inline]
 __se_sys_exit_group kernel/exit.c:1121 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88802b131300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802b131380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b131400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88802b131480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802b131500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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