syzbot

syz-executor246 (7180): drop_caches: 2
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BUG: KASAN: stack-out-of-bounds in __lock_acquire+0x11c/0x7f70 kernel/locking/lockdep.c:5004
Read of size 8 at addr ffffc9000f757898 by task syz-executor246/7180

CPU: 1 PID: 7180 Comm: syz-executor246 Not tainted 6.6.0-syzkaller-16201-gb57b17e88bf5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0x163/0x540 mm/kasan/report.c:475
 kasan_report+0x142/0x170 mm/kasan/report.c:588
 __lock_acquire+0x11c/0x7f70 kernel/locking/lockdep.c:5004
 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
 down+0x39/0xc0 kernel/locking/semaphore.c:59
 xfs_buf_lock+0x154/0x4b0 fs/xfs/xfs_buf.c:1126
 xfs_buf_delwri_submit_buffers+0x14d/0x8e0 fs/xfs/xfs_buf.c:2174
 xfs_buf_delwri_submit+0xba/0x260 fs/xfs/xfs_buf.c:2252
 xfs_qm_shrink_scan+0x1ee/0x400 fs/xfs/xfs_qm.c:521
 do_shrink_slab+0x6ed/0x1120 mm/shrinker.c:435
 shrink_slab+0x1092/0x14c0 mm/shrinker.c:662
 drop_slab_node mm/vmscan.c:387 [inline]
 drop_slab+0x148/0x280 mm/vmscan.c:405
 drop_caches_sysctl_handler+0xbc/0x160 fs/drop_caches.c:68
 proc_sys_call_handler+0x546/0x8a0 fs/proc/proc_sysctl.c:600
 do_iter_write+0x7ac/0xcb0 fs/read_write.c:860
 iter_file_splice_write+0x86d/0x1010 fs/splice.c:736
 do_splice_from fs/splice.c:933 [inline]
 direct_splice_actor+0xea/0x1c0 fs/splice.c:1142
 splice_direct_to_actor+0x376/0x9e0 fs/splice.c:1088
 do_splice_direct+0x2ac/0x3f0 fs/splice.c:1194
 do_sendfile+0x62c/0x1000 fs/read_write.c:1254
 __do_sys_sendfile64 fs/read_write.c:1316 [inline]
 __se_sys_sendfile64+0x100/0x1e0 fs/read_write.c:1308
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f6da0b30f59
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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:00007ffdca46db28 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007ffdca46db30 RCX: 00007f6da0b30f59
RDX: 0000000020002080 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 0000000000000000 R08: 65732f636f72702f R09: 65732f636f72702f
R10: 000000000000023b R11: 0000000000000246 R12: 00007ffdca46dbdc
R13: 0000000000000027 R14: 431bde82d7b634db R15: 00007ffdca46dc10
 </TASK>

The buggy address belongs to the virtual mapping at
 [ffffc9000f750000, ffffc9000f759000) created by:
 copy_process+0x5d1/0x3fb0 kernel/fork.c:2332

The buggy address belongs to the physical page:
page:ffffea00005cdd80 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x17376
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO), pid 2, tgid 2 (kthreadd), ts 155944385071, free_ts 154428140707
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1544 [inline]
 get_page_from_freelist+0x339a/0x3530 mm/page_alloc.c:3312
 __alloc_pages+0x255/0x670 mm/page_alloc.c:4568
 alloc_pages_mpol+0x3de/0x640 mm/mempolicy.c:2133
 vm_area_alloc_pages mm/vmalloc.c:3063 [inline]
 __vmalloc_area_node mm/vmalloc.c:3139 [inline]
 __vmalloc_node_range+0x9a3/0x1490 mm/vmalloc.c:3320
 alloc_thread_stack_node kernel/fork.c:309 [inline]
 dup_task_struct+0x3e5/0x7d0 kernel/fork.c:1118
 copy_process+0x5d1/0x3fb0 kernel/fork.c:2332
 kernel_clone+0x222/0x840 kernel/fork.c:2907
 kernel_thread+0x1bc/0x230 kernel/fork.c:2969
 create_kthread kernel/kthread.c:411 [inline]
 kthreadd+0x60c/0x810 kernel/kthread.c:764
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1137 [inline]
 free_unref_page_prepare+0x92a/0xa50 mm/page_alloc.c:2347
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2487
 mm_free_pgd kernel/fork.c:803 [inline]
 __mmdrop+0xb8/0x3d0 kernel/fork.c:919
 exit_mm+0x21f/0x300 kernel/exit.c:567
 do_exit+0x9b7/0x2750 kernel/exit.c:858
 do_group_exit+0x206/0x2c0 kernel/exit.c:1021
 __do_sys_exit_group kernel/exit.c:1032 [inline]
 __se_sys_exit_group kernel/exit.c:1030 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1030
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Memory state around the buggy address:
 ffffc9000f757780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000f757800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9000f757880: f3 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
                            ^
 ffffc9000f757900: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
 ffffc9000f757980: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
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