syzbot

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BUG: KASAN: stack-out-of-bounds in atomic_dec include/asm-generic/atomic-instrumented.h:329 [inline]
BUG: KASAN: stack-out-of-bounds in mapping_unmap_writable include/linux/fs.h:604 [inline]
BUG: KASAN: stack-out-of-bounds in __remove_shared_vm_struct mm/mmap.c:146 [inline]
BUG: KASAN: stack-out-of-bounds in unlink_file_vma+0x17e/0x1b0 mm/mmap.c:164
Write of size 4 at addr ffff8881dd277bec by task syz.9.2546/9407

CPU: 1 PID: 9407 Comm: syz.9.2546 Not tainted 5.4.289-syzkaller-00011-g39762b7a60e9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x241 lib/dump_stack.c:118
 print_address_description+0x8c/0x600 mm/kasan/report.c:384
 __kasan_report+0xf3/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 check_memory_region_inline mm/kasan/generic.c:141 [inline]
 check_memory_region+0x272/0x280 mm/kasan/generic.c:191
 atomic_dec include/asm-generic/atomic-instrumented.h:329 [inline]
 mapping_unmap_writable include/linux/fs.h:604 [inline]
 __remove_shared_vm_struct mm/mmap.c:146 [inline]
 unlink_file_vma+0x17e/0x1b0 mm/mmap.c:164
 free_pgtables+0x135/0x280 mm/memory.c:428
 exit_mmap+0x2cb/0x520 mm/mmap.c:3192
 __mmput+0x8e/0x2c0 kernel/fork.c:1101
 exit_mm kernel/exit.c:538 [inline]
 do_exit+0xc08/0x2bc0 kernel/exit.c:848
 do_group_exit+0x138/0x300 kernel/exit.c:984
 get_signal+0xdb1/0x1440 kernel/signal.c:2738
 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7f4709854de9
Code: Bad RIP value.
RSP: 002b:00007f4707ebf0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f4709a6dfa8 RCX: 00007f4709854de9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4709a6dfa8
RBP: 00007f4709a6dfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4709a6dfac
R13: 0000000000000000 R14: 00007ffd602b5e50 R15: 00007ffd602b5f38

The buggy address belongs to the page:
page:ffffea0007749dc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 0000000000000000 ffffea0007749d88 0000000000000000
raw: 0000000000000000 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 0x500dc0(GFP_USER|__GFP_ZERO|__GFP_ACCOUNT)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x18f/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893
 __alloc_pages include/linux/gfp.h:503 [inline]
 __alloc_pages_node include/linux/gfp.h:516 [inline]
 alloc_pages_node include/linux/gfp.h:530 [inline]
 alloc_thread_stack_node kernel/fork.c:259 [inline]
 dup_task_struct+0x85/0x600 kernel/fork.c:886
 copy_process+0x56d/0x3230 kernel/fork.c:1889
 _do_fork+0x197/0x900 kernel/fork.c:2399
 __do_sys_clone3 kernel/fork.c:2688 [inline]
 __se_sys_clone3 kernel/fork.c:2675 [inline]
 __x64_sys_clone3+0x2da/0x300 kernel/fork.c:2675
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 __free_pages_ok+0x847/0x950 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4955 [inline]
 __free_pages+0x91/0x140 mm/page_alloc.c:4961
 __free_slab+0x221/0x2e0 mm/slub.c:1774
 __slab_free+0x34b/0x360 mm/slub.c:3012
 qlist_free_all+0x43/0xb0 mm/kasan/quarantine.c:167
 quarantine_reduce+0x1d9/0x210 mm/kasan/quarantine.c:260
 __kasan_kmalloc+0x41/0x210 mm/kasan/common.c:507
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842
 getname_flags+0xb8/0x4e0 fs/namei.c:141
 do_sys_open+0x357/0x810 fs/open.c:1117
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881dd277a80: 04 f2 04 f2 04 f2 00 f2 f2 f2 04 f2 00 00 00 00
 ffff8881dd277b00: 00 00 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2
>ffff8881dd277b80: 04 f2 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2
                                                          ^
 ffff8881dd277c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881dd277c80: 00 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 f2 f2
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