syzbot

RDX: 0000777d5931ae01 RSI: ffffffff8c0ae220 RDI: ffffffff8c607c40
RBP: ffffc9000a52f6b8 R08: ffffffff8142a345 R09: 1ffffffff202fc75
R10: dffffc0000000000 R11: fffffbfff202fc76 R12: ffffffff94f22ec8
==================================================================
BUG: KASAN: stack-out-of-bounds in __show_regs+0x23e/0x610 arch/x86/kernel/process_64.c:91
Read of size 8 at addr ffffc9000a52f538 by task syz.2.281/6524

CPU: 1 UID: 0 PID: 6524 Comm: syz.2.281 Not tainted 6.10.0-next-20240726-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 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
 __show_regs+0x23e/0x610 arch/x86/kernel/process_64.c:91
 show_trace_log_lvl+0x3d4/0x520 arch/x86/kernel/dumpstack.c:301
 sched_show_task+0x506/0x6d0 kernel/sched/core.c:7512
 report_rtnl_holders+0x327/0x400 net/core/rtnetlink.c:110
 call_timer_fn+0x18e/0x650 kernel/time/timer.c:1792
 expire_timers kernel/time/timer.c:1843 [inline]
 __run_timers kernel/time/timer.c:2417 [inline]
 __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2428
 run_timer_base kernel/time/timer.c:2437 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2447
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 8e be 37 f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 83 4f 9f f5 65 8b 05 04 46 40 74 85 c0 74 43 48 c7 04 24 0e 36
RSP: 0000:ffffc900033f6f40 EFLAGS: 00000206
RAX: 1472595bd3dec300 RBX: 1ffff9200067edec RCX: ffffffff94f2f903
RDX: dffffc0000000000 RSI: ffffffff8c0ad540 RDI: 0000000000000001
RBP: ffffc900033f6fd0 R08: ffffffff9017e3af R09: 1ffffffff202fc75
R10: dffffc0000000000 R11: fffffbfff202fc76 R12: dffffc0000000000
R13: 1ffff9200067ede8 R14: ffffc900033f6f60 R15: 0000000000000246
 __debug_check_no_obj_freed lib/debugobjects.c:999 [inline]
 debug_check_no_obj_freed+0x561/0x580 lib/debugobjects.c:1020
 free_pages_prepare mm/page_alloc.c:1101 [inline]
 free_unref_folios+0x5cb/0x1b00 mm/page_alloc.c:2660
 folios_put_refs+0x76e/0x860 mm/swap.c:1039
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x6de/0x1df0 mm/shmem.c:1023
 shmem_truncate_range mm/shmem.c:1132 [inline]
 shmem_evict_inode+0x29b/0xa80 mm/shmem.c:1260
 evict+0x2a8/0x630 fs/inode.c:669
 __dentry_kill+0x20d/0x630 fs/dcache.c:610
 dput+0x19f/0x2b0 fs/dcache.c:852
 __fput+0x5f8/0x8a0 fs/file_table.c:430
 task_work_run+0x24f/0x310 kernel/task_work.c:222
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xa2f/0x27f0 kernel/exit.c:882
 do_group_exit+0x207/0x2c0 kernel/exit.c:1031
 get_signal+0x16a1/0x1740 kernel/signal.c:2917
 arch_do_signal_or_restart+0x96/0x830 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdfc3777299
Code: Unable to access opcode bytes at 0x7fdfc377726f.
RSP: 002b:00007fdfc45800f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fdfc3906060 RCX: 00007fdfc3777299
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fdfc3906060
RBP: 00007fdfc3906058 R08: 00007fdfc45806c0 R09: 00007fdfc45806c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fdfc3906064
R13: 000000000000006e R14: 00007fffcfe03f50 R15: 00007fffcfe04038
 </TASK>

The buggy address belongs to the virtual mapping at
 [ffffc9000a528000, ffffc9000a531000) created by:
 copy_process+0x5d1/0x3d90 kernel/fork.c:2206

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27ecd
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
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 10960457662, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3442
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4700
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2263
 vm_area_alloc_pages mm/vmalloc.c:3584 [inline]
 __vmalloc_area_node mm/vmalloc.c:3660 [inline]
 __vmalloc_node_range_noprof+0x971/0x1460 mm/vmalloc.c:3841
 alloc_thread_stack_node kernel/fork.c:314 [inline]
 dup_task_struct+0x444/0x8c0 kernel/fork.c:1115
 copy_process+0x5d1/0x3d90 kernel/fork.c:2206
 kernel_clone+0x226/0x8f0 kernel/fork.c:2788
 kernel_thread+0x1bc/0x240 kernel/fork.c:2850
 create_kthread kernel/kthread.c:412 [inline]
 kthreadd+0x60d/0x810 kernel/kthread.c:765
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:144
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
page_owner free stack trace missing

Memory state around the buggy address:
 ffffc9000a52f400: f2 f2 00 00 00 00 00 00 f2 f2 f2 f2 00 00 00 00
 ffffc9000a52f480: 00 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
>ffffc9000a52f500: 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 00 f3 f3 f3
                                        ^
 ffffc9000a52f580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000a52f600: f1 f1 f1 f1 00 f2 f2 f2 00 f3 f3 f3 00 00 00 00
==================================================================
----------------
Code disassembly (best guess):
   0:	9c                   	pushf
   1:	8f 44 24 20          	pop    0x20(%rsp)
   5:	42 80 3c 23 00       	cmpb   $0x0,(%rbx,%r12,1)
   a:	74 08                	je     0x14
   c:	4c 89 f7             	mov    %r14,%rdi
   f:	e8 8e be 37 f6       	call   0xf637bea2
  14:	f6 44 24 21 02       	testb  $0x2,0x21(%rsp)
  19:	75 52                	jne    0x6d
  1b:	41 f7 c7 00 02 00 00 	test   $0x200,%r15d
  22:	74 01                	je     0x25
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
* 2a:	e8 83 4f 9f f5       	call   0xf59f4fb2 <-- trapping instruction
  2f:	65 8b 05 04 46 40 74 	mov    %gs:0x74404604(%rip),%eax        # 0x7440463a
  36:	85 c0                	test   %eax,%eax
  38:	74 43                	je     0x7d
  3a:	48                   	rex.W
  3b:	c7                   	.byte 0xc7
  3c:	04 24                	add    $0x24,%al
  3e:	0e                   	(bad)
  3f:	36                   	ss