Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 10386 Comm: syz.7.1028 Not tainted 6.16.0-rc2-next-20250620-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pidfs_free_pid+0xaf/0x140 fs/pidfs.c:162
Code: f0 ff ff 73 e4 43 80 3c 3c 00 74 08 4c 89 f7 e8 67 19 de ff 49 83 3e 00 0f 85 84 00 00 00 e8 78 ee 79 ff 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 42 19 de ff 4c 8b 33 4d 85 f6 74
RSP: 0018:ffffc90000007b90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8880287e3c00
RDX: 0000000000000100 RSI: 0000000000000001 RDI: ffff8880765c8070
RBP: 0000000000000001 R08: ffff8880765c8003 R09: 1ffff1100ecb9000
R10: dffffc0000000000 R11: ffffed100ecb9001 R12: 1ffff1100ecb900d
R13: ffffffff81a8bfb4 R14: ffff8880765c8068 R15: dffffc0000000000
FS:  00007fe7e72486c0(0000) GS:ffff888125c26000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055da20b42008 CR3: 0000000031dec000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000ffff000c DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 put_pid+0x9c/0x130 kernel/pid.c:103
 rcu_do_batch kernel/rcu/tree.c:2582 [inline]
 rcu_core+0xca5/0x1710 kernel/rcu/tree.c:2838
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__rcu_read_unlock+0x6a/0xe0 kernel/rcu/tree_plugin.h:445
Code: 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 75 66 41 83 3e 00 75 27 43 0f b6 04 3c 84 c0 75 41 8b 03 3d 00 00 00 40 73 0f <5b> 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc cc 90 0f 0b 90 eb eb e8
RSP: 0018:ffffc900044eec68 EFLAGS: 00000287
RAX: 0000000000000000 RBX: ffff8880287e4044 RCX: c945f03e32c66000
RDX: 0000000000000001 RSI: ffffffff8db7f40a RDI: ffff8880287e3c00
RBP: dffffc0000000000 R08: ffffc900044efee0 R09: 0000000000000000
R10: ffffc900044eedb8 R11: fffff5200089ddb9 R12: 1ffff110050fc808
R13: ffffc900044e8000 R14: ffff8880287e4048 R15: dffffc0000000000
 rcu_read_unlock include/linux/rcupdate.h:873 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x19ae/0x2390 arch/x86/kernel/unwind_orc.c:680
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf5/0x1f0 mm/page_owner.c:156
 __set_page_owner+0x8d/0x4a0 mm/page_owner.c:329
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2438
 shmem_alloc_folio mm/shmem.c:1847 [inline]
 shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1886
 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2532
 shmem_fault+0x179/0x390 mm/shmem.c:2733
 __do_fault+0x138/0x390 mm/memory.c:5187
 do_read_fault mm/memory.c:5608 [inline]
 do_fault mm/memory.c:5742 [inline]
 do_pte_missing mm/memory.c:4269 [inline]
 handle_pte_fault mm/memory.c:6087 [inline]
 __handle_mm_fault+0x37ed/0x5620 mm/memory.c:6230
 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6399
 faultin_page mm/gup.c:1186 [inline]
 __get_user_pages+0x1aef/0x30b0 mm/gup.c:1488
 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1922
 __mm_populate+0x24c/0x380 mm/gup.c:2025
 mm_populate include/linux/mm.h:3372 [inline]
 vm_mmap_pgoff+0x3f0/0x4c0 mm/util.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe7e638e929
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe7e7248038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fe7e65b5fa0 RCX: 00007fe7e638e929
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fe7e6410b39 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe7e65b5fa0 R15: 00007ffe6be688f8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:pidfs_free_pid+0xaf/0x140 fs/pidfs.c:162
Code: f0 ff ff 73 e4 43 80 3c 3c 00 74 08 4c 89 f7 e8 67 19 de ff 49 83 3e 00 0f 85 84 00 00 00 e8 78 ee 79 ff 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 42 19 de ff 4c 8b 33 4d 85 f6 74
RSP: 0018:ffffc90000007b90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8880287e3c00
RDX: 0000000000000100 RSI: 0000000000000001 RDI: ffff8880765c8070
RBP: 0000000000000001 R08: ffff8880765c8003 R09: 1ffff1100ecb9000
R10: dffffc0000000000 R11: ffffed100ecb9001 R12: 1ffff1100ecb900d
R13: ffffffff81a8bfb4 R14: ffff8880765c8068 R15: dffffc0000000000
FS:  00007fe7e72486c0(0000) GS:ffff888125c26000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055da20b42008 CR3: 0000000031dec000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000ffff000c DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	f0 ff                	lock (bad)
   2:	ff 73 e4             	push   -0x1c(%rbx)
   5:	43 80 3c 3c 00       	cmpb   $0x0,(%r12,%r15,1)
   a:	74 08                	je     0x14
   c:	4c 89 f7             	mov    %r14,%rdi
   f:	e8 67 19 de ff       	call   0xffde197b
  14:	49 83 3e 00          	cmpq   $0x0,(%r14)
  18:	0f 85 84 00 00 00    	jne    0xa2
  1e:	e8 78 ee 79 ff       	call   0xff79ee9b
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 42 19 de ff       	call   0xffde197b
  39:	4c 8b 33             	mov    (%rbx),%r14
  3c:	4d 85 f6             	test   %r14,%r14
  3f:	74                   	.byte 0x74