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BUG: KASAN: stack-out-of-bounds in collapse_file+0x4edf/0x5830 mm/khugepaged.c:2038
Read of size 8 at addr ffffc9000c7ff908 by task syz-executor.4/9791

CPU: 0 PID: 9791 Comm: syz-executor.4 Not tainted 6.1.0-rc5-next-20221115-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:253 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:364
 kasan_report+0xbf/0x1f0 mm/kasan/report.c:464
 collapse_file+0x4edf/0x5830 mm/khugepaged.c:2038
 hpage_collapse_scan_file+0xdba/0x18e0 mm/khugepaged.c:2237
 madvise_collapse+0x523/0xb60 mm/khugepaged.c:2696
 madvise_vma_behavior+0x666/0x1fd0 mm/madvise.c:1092
 madvise_walk_vmas+0x1c7/0x2b0 mm/madvise.c:1266
 do_madvise+0x2fa/0x3e0 mm/madvise.c:1445
 __do_sys_madvise mm/madvise.c:1458 [inline]
 __se_sys_madvise mm/madvise.c:1456 [inline]
 __x64_sys_madvise+0xaa/0x110 mm/madvise.c:1456
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f089828b639
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0898f9c168 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f08983abf80 RCX: 00007f089828b639
RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000000020000000
RBP: 00007f08982e6ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd4fdc27ef R14: 00007f0898f9c300 R15: 0000000000022000
 </TASK>

The buggy address belongs to stack of task syz-executor.4/9791
 and is located at offset 120 in frame:
 collapse_file+0x0/0x5830 arch/x86/include/asm/bitops.h:207

This frame has 4 objects:
 [32, 40) 'hpage'
 [64, 72) 'folio'
 [96, 112) 'pagelist'
 [128, 184) 'xas'

The buggy address belongs to the virtual mapping at
 [ffffc9000c7f8000, ffffc9000c801000) created by:
 kernel_clone+0xeb/0xa40 kernel/fork.c:2681

The buggy address belongs to the physical page:
page:ffffea0001e89040 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7a241
memcg:ffff888076868b82
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff888076868b82
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 9769, tgid 9769 (syz-executor.4), ts 557324794425, free_ts 556638123762
 prep_new_page mm/page_alloc.c:2561 [inline]
 get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4310
 __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5569
 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285
 vm_area_alloc_pages mm/vmalloc.c:2989 [inline]
 __vmalloc_area_node mm/vmalloc.c:3057 [inline]
 __vmalloc_node_range+0x975/0x13c0 mm/vmalloc.c:3227
 alloc_thread_stack_node kernel/fork.c:311 [inline]
 dup_task_struct kernel/fork.c:987 [inline]
 copy_process+0x12d2/0x75c0 kernel/fork.c:2097
 kernel_clone+0xeb/0xa40 kernel/fork.c:2681
 __do_sys_clone+0xba/0x100 kernel/fork.c:2822
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1468 [inline]
 free_pcp_prepare+0x65c/0xc00 mm/page_alloc.c:1518
 free_unref_page_prepare mm/page_alloc.c:3409 [inline]
 free_unref_page_list+0x176/0xc40 mm/page_alloc.c:3551
 release_pages+0x3a2/0x1290 mm/swap.c:1074
 tlb_batch_pages_flush+0xa8/0x1a0 mm/mmu_gather.c:90
 tlb_flush_mmu_free mm/mmu_gather.c:287 [inline]
 tlb_flush_mmu mm/mmu_gather.c:294 [inline]
 tlb_finish_mmu+0x14b/0x7e0 mm/mmu_gather.c:386
 exit_mmap+0x202/0x7b0 mm/mmap.c:3105
 __mmput+0x128/0x4c0 kernel/fork.c:1207
 mmput+0x60/0x70 kernel/fork.c:1229
 exit_mm kernel/exit.c:516 [inline]
 do_exit+0x9ac/0x28d0 kernel/exit.c:807
 do_group_exit+0xd4/0x2a0 kernel/exit.c:950
 get_signal+0x21b1/0x2440 kernel/signal.c:2858
 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306
 exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
 exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296
 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffffc9000c7ff800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000c7ff880: 00 00 f1 f1 f1 f1 00 f2 f2 f2 00 f2 f2 f2 00 00
>ffffc9000c7ff900: f2 f2 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 00 00
                      ^
 ffffc9000c7ff980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000c7ffa00: 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00
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