syzbot

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 0 P4D 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.4.290-syzkaller-00002-g41adfeb3d639 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events bpf_map_free_deferred
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d18 EFLAGS: 00010206
RAX: ffffffff8154e8ca RBX: 0000000000000100 RCX: ffff8881f5d64ec0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881d9d271c0
RBP: ffff8881f6e09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffff9b40
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d9d271c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d8f8c000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 call_timer_fn+0x36/0x390 kernel/time/timer.c:1448
 expire_timers kernel/time/timer.c:1493 [inline]
 __run_timers+0x879/0xbe0 kernel/time/timer.c:1817
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830
 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x195/0x1c0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:539 [inline]
 smp_apic_timer_interrupt+0x11a/0x490 arch/x86/kernel/apic/apic.c:1161
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834
 </IRQ>
RIP: 0010:arch_stack_walk+0xed/0x140 arch/x86/kernel/stacktrace.c:26
Code: 0b 00 00 eb 03 48 89 e9 48 8d bd 70 ff ff ff 4c 89 e6 4c 89 fa e8 53 0a 06 00 83 bd 70 ff ff ff 00 74 34 48 8d 9d 70 ff ff ff <48> 89 df e8 6b e6 05 00 48 85 c0 74 20 4c 89 f7 48 89 c6 31 d2 41
RSP: 0018:ffff8881f5da7820 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000080000001 RBX: ffff8881f5da7820 RCX: e83deeeaa0fcf100
RDX: ffff8881f5da7860 RSI: ffff8881f5da74a0 RDI: 0000000000000001
RBP: ffff8881f5da78b0 R08: dffffc0000000000 R09: ffff8881f5da7870
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8881f5d64ec0
R13: ffffffff8153c430 R14: ffff8881f5da7900 R15: 0000000000000000
 stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123
 save_stack+0x95/0x880 mm/page_owner.c:122
 __reset_page_owner+0x1f/0x100 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 free_pcp_prepare mm/page_alloc.c:1233 [inline]
 free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085
 free_unref_page mm/page_alloc.c:3134 [inline]
 free_the_page mm/page_alloc.c:4953 [inline]
 __free_pages+0xaf/0x140 mm/page_alloc.c:4961
 __vunmap+0x75b/0x890 mm/vmalloc.c:2260
 htab_free_elems kernel/bpf/hashtab.c:116 [inline]
 prealloc_destroy kernel/bpf/hashtab.c:194 [inline]
 htab_map_free+0x515/0x670 kernel/bpf/hashtab.c:1238
 bpf_map_free_deferred+0xa8/0x100 kernel/bpf/syscall.c:311
 process_one_work+0x765/0xd20 kernel/workqueue.c:2290
 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436
 kthread+0x2da/0x360 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354
Modules linked in:
CR2: 0000000000000000
---[ end trace 24f2c7bca5dc6bf2 ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6e09d18 EFLAGS: 00010206
RAX: ffffffff8154e8ca RBX: 0000000000000100 RCX: ffff8881f5d64ec0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8881d9d271c0
RBP: ffff8881f6e09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffff9b40
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d9d271c0
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001d8f8c000 CR4: 00000000003406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	00 00                	add    %al,(%rax)
   2:	eb 03                	jmp    0x7
   4:	48 89 e9             	mov    %rbp,%rcx
   7:	48 8d bd 70 ff ff ff 	lea    -0x90(%rbp),%rdi
   e:	4c 89 e6             	mov    %r12,%rsi
  11:	4c 89 fa             	mov    %r15,%rdx
  14:	e8 53 0a 06 00       	call   0x60a6c
  19:	83 bd 70 ff ff ff 00 	cmpl   $0x0,-0x90(%rbp)
  20:	74 34                	je     0x56
  22:	48 8d 9d 70 ff ff ff 	lea    -0x90(%rbp),%rbx
* 29:	48 89 df             	mov    %rbx,%rdi <-- trapping instruction
  2c:	e8 6b e6 05 00       	call   0x5e69c
  31:	48 85 c0             	test   %rax,%rax
  34:	74 20                	je     0x56
  36:	4c 89 f7             	mov    %r14,%rdi
  39:	48 89 c6             	mov    %rax,%rsi
  3c:	31 d2                	xor    %edx,%edx
  3e:	41                   	rex.B