syzbot


WARNING in rcu_check_gp_start_stall

Status: upstream: reported on 2025/06/17 13:49
Reported-by: syzbot+6af04f09bb7a907b0789@syzkaller.appspotmail.com
First crash: 38d, last: 11h52m
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in rcu_check_gp_start_stall net -1 C done error 2628 1h50m 2345d 0/29 upstream: reported C repro on 2019/02/22 17:10
linux-5.15 WARNING in rcu_check_gp_start_stall (3) -1 1 23d 23d 0/3 upstream: reported on 2025/07/02 22:12
linux-5.15 WARNING in rcu_check_gp_start_stall (2) -1 7 312d 457d 0/3 auto-obsoleted due to no activity on 2024/12/25 11:45
linux-5.15 WARNING in rcu_check_gp_start_stall -1 1 595d 595d 0/3 auto-obsoleted due to no activity on 2024/03/17 09:39
linux-6.1 WARNING in rcu_check_gp_start_stall origin:upstream missing-backport -1 C done 14 44d 677d 0/3 upstream: reported C repro on 2023/09/17 20:24

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at kernel/rcu/tree_stall.h:1001 rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:993
Modules linked in:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.6.100-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:1001
Code: ff ff ff 48 c7 c7 a0 c4 ee 96 be 04 00 00 00 e8 2a a8 6c 00 48 89 df b8 01 00 00 00 87 05 5c 8f 7e 15 85 c0 0f 85 19 ff ff ff <0f> 0b 48 81 ff 00 54 d3 8c 74 47 48 c7 c0 5c b2 4a 8e 48 c1 e8 03
RSP: 0018:ffffc900001f0bb8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff8cd35400 RCX: ffffffff81703536
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8cd35400
RBP: ffffc900001f0e30 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff2ddd894 R12: 0000000000002904
R13: 1ffff110171e7a6a R14: 0000000000000a02 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f88679b7bac CR3: 000000002bf8a000 CR4: 00000000003526e0
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:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d e3 16 3b 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c6
RAX: fc28ccea9031b600 RBX: ffffffff81619a5b RCX: fc28ccea9031b600
RDX: 0000000000000001 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6700
RBP: ffffc90000187f20 R08: ffff8880b8f36d4b R09: 1ffff110171e6da9
R10: dffffc0000000000 R11: ffffed10171e6daa R12: ffffffff8e4a7da8
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100364e780
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>
----------------
Code disassembly (best guess):
   0:	cc                   	int3
   1:	cc                   	int3
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	cc                   	int3
   7:	f3 0f 1e fa          	endbr64
   b:	0f 0b                	ud2
   d:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
  14:	00 00 00
  17:	f3 0f 1e fa          	endbr64
  1b:	66 90                	xchg   %ax,%ax
  1d:	0f 00 2d e3 16 3b 00 	verw   0x3b16e3(%rip)        # 0x3b1707
  24:	f3 0f 1e fa          	endbr64
  28:	fb                   	sti
  29:	f4                   	hlt
* 2a:	c3                   	ret <-- trapping instruction
  2b:	cc                   	int3
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	cc                   	int3
  31:	cc                   	int3
  32:	cc                   	int3
  33:	cc                   	int3
  34:	cc                   	int3
  35:	cc                   	int3
  36:	cc                   	int3
  37:	66 0f 1f 00          	nopw   (%rax)
  3b:	55                   	push   %rbp
  3c:	41 57                	push   %r15
  3e:	41 56                	push   %r14

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/25 11:35 linux-6.6.y dbcb8d8e4163 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/17 22:02 linux-6.6.y 9247f4e6573a 0d1223f1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/11 23:50 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/11 05:40 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/11 05:39 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/10 07:05 linux-6.6.y a5df3a702b2c 956bd956 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/09 11:55 linux-6.6.y a5df3a702b2c f4e5e155 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/06 09:26 linux-6.6.y 3f5b4c104b7d 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/05 12:57 linux-6.6.y 3f5b4c104b7d 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/07/05 12:26 linux-6.6.y 3f5b4c104b7d 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/30 00:55 linux-6.6.y 3f5b4c104b7d fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/28 13:33 linux-6.6.y 3f5b4c104b7d fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/27 09:13 linux-6.6.y 6282921b6825 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/25 11:06 linux-6.6.y 6282921b6825 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/25 04:32 linux-6.6.y 6282921b6825 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/24 01:14 linux-6.6.y 6282921b6825 e2f27c35 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/20 20:45 linux-6.6.y 6282921b6825 804b3919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/18 02:15 linux-6.6.y c2603c511feb e77fae15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/17 13:52 linux-6.6.y c2603c511feb cfebc887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
2025/06/17 13:48 linux-6.6.y c2603c511feb cfebc887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in rcu_check_gp_start_stall
* Struck through repros no longer work on HEAD.