------------[ cut here ]------------
WARNING: CPU: 0 PID: 18920 at kernel/rcu/tree_stall.h:1001 rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:993
Modules linked in:
CPU: 0 PID: 18920 Comm: syz.3.4065 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:1001
Code: ff ff ff 48 c7 c7 a0 04 ef 96 be 04 00 00 00 e8 9a ba 6c 00 48 89 df b8 01 00 00 00 87 05 7c d9 7e 15 85 c0 0f 85 19 ff ff ff <0f> 0b 48 81 ff 80 51 d3 8c 74 47 48 c7 c0 1c ba 4a 8e 48 c1 e8 03
RSP: 0018:ffffc90000007bb8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff8cd35180 RCX: ffffffff81702b16
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8cd35180
RBP: ffffc90000007e30 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff2dde094 R12: 0000000000002904
R13: 1ffff110171c7a22 R14: 0000000000000a02 R15: dffffc0000000000
FS:  00007efd3be316c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efd3be31000 CR3: 000000004158c000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 rcu_core+0x612/0x1720 kernel/rcu/tree.c:2462
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00
RSP: 0018:ffffc90004187a80 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 10031c6e9d225800
RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc64c0
RBP: ffffc90004187b88 R08: dffffc0000000000 R09: 1ffffffff21b4ea6
R10: dffffc0000000000 R11: fffffbfff21b4ea7 R12: 1ffff92000830f5c
R13: ffff88802cdc14a0 R14: 0000000000000246 R15: dffffc0000000000
 __might_fault+0xc6/0x120 mm/memory.c:5946
 _copy_from_user+0x2a/0xe0 lib/usercopy.c:14
 copy_from_user include/linux/uaccess.h:183 [inline]
 restore_altstack+0x9e/0x4a0 kernel/signal.c:4290
 __ia32_sys_rt_sigreturn+0x1f6/0x7b0 arch/x86/kernel/signal_64.c:263
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7efd3af2af79
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007efd3be30b40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007efd3b1e6098 RCX: 00007efd3af2af79
RDX: 00007efd3be30b40 RSI: 00007efd3be30c70 RDI: 0000000000000011
RBP: 00007efd3b1e6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efd3b1e6128 R14: 00007ffe14646ca0 R15: 00007ffe14646d88
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 9c 8f 84 24 80 00 	add    %bl,0x802484(%rdi,%rcx,4)
   7:	00 00                	add    %al,(%rax)
   9:	f6 84 24 81 00 00 00 	testb  $0x2,0x81(%rsp)
  10:	02
  11:	0f 85 f5 00 00 00    	jne    0x10c
  17:	41 f7 c6 00 02 00 00 	test   $0x200,%r14d
  1e:	74 01                	je     0x21
  20:	fb                   	sti
  21:	48 c7 44 24 60 0e 36 	movq   $0x45e0360e,0x60(%rsp)
  28:	e0 45
* 2a:	4b c7 04 3c 00 00 00 	movq   $0x0,(%r12,%r15,1) <-- trapping instruction
  31:	00
  32:	66 43 c7 44 3c 09 00 	movw   $0x0,0x9(%r12,%r15,1)
  39:	00
  3a:	43 c6 44 3c 0b 00    	movb   $0x0,0xb(%r12,%r15,1)