syzbot


INFO: rcu detected stall in sys_recvmsg

Status: upstream: reported on 2025/08/10 06:16
Reported-by: syzbot+624e0eff6200cf7fb62e@syzkaller.appspotmail.com
First crash: 133d, last: 3d20h
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in sys_recvmsg 1 1 156d 156d 0/3 auto-obsoleted due to no activity on 2025/10/25 13:40
linux-6.6 INFO: rcu detected stall in sys_recvmsg 1 2 115d 115d 0/2 auto-obsoleted due to no activity on 2025/12/05 18:53
android-5-15 BUG: soft lockup in sys_recvmsg 1 10 547d 634d 0/2 auto-obsoleted due to no activity on 2024/09/19 17:52
android-5-10 BUG: soft lockup in sys_recvmsg (2) 1 C error 2 62d 242d 0/2 upstream: reported C repro on 2025/04/23 03:10
android-5-10 BUG: soft lockup in sys_recvmsg 1 4 532d 610d 0/2 auto-obsoleted due to no activity on 2024/10/05 13:04

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=6cb/1/0x4000000000000002 softirq=15747/15748 fqs=2100 
	(detected by 1, t=10505 jiffies, g=20569, q=1875)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7095 Comm: syz.6.641 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:native_apic_msr_eoi_write+0xb/0x10 arch/x86/include/asm/apic.h:214
Code: 8b 06 bf f0 03 00 00 89 de 5b 41 5e 41 5f ff e0 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b9 0b 08 00 00 31 c0 31 d2 0f 30 <c3> 0f 1f 40 00 81 ff cf 00 00 00 7f 0c 83 ff 20 74 2a 83 ff 30 74
RSP: 0018:ffffc90000007a00 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffffff8bbc09c8 RCX: 000000000000080b
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000000b0
RBP: 0000000000000000 R08: ffffffff8eebf008 R09: ffffffff8eebf018
R10: ffffffff8eebf010 R11: ffffffff8eebf003 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007fca2e5646c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000004f000 CR3: 0000000055359000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 apic_eoi arch/x86/include/asm/apic.h:400 [inline]
 ack_APIC_irq arch/x86/include/asm/apic.h:446 [inline]
 __sysvec_irq_work+0x51/0x240 arch/x86/kernel/irq_work.c:19
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0x4a/0xc0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc90000007ae0 EFLAGS: 00000206
RAX: 9205cca36af4e800 RBX: 1ffff92000000f60 RCX: 9205cca36af4e800
RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: ffffffff8a59e800
RBP: ffffc90000007bb8 R08: dffffc0000000000 R09: fffffbfff1ff541f
R10: fffffbfff1ff541f R11: 1ffffffff1ff541e R12: ffffffff8c120c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 ieee80211_iterate_active_interfaces_atomic+0x132/0x140 net/mac80211/util.c:831
 mac80211_hwsim_beacon+0x9b/0x180 drivers/net/wireless/mac80211_hwsim.c:1865
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
 handle_softirqs+0x328/0x820 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202
Code: 66 2e 0f 1f 84 00 00 00 00 00 53 48 89 fb e8 17 00 00 00 48 8b 3d d0 6b f1 0b 48 89 de 5b e9 d7 9e 43 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d a4 a3 8a 7e 65 8b 15 a5 a3 8a 7e 81 e2 00
RSP: 0018:ffffc9000314f5a8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000008 RCX: ffff888028708000
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: dffffc0000000000 R09: ffffed100471d399
R10: ffffed100471d399 R11: 1ffff1100471d398 R12: ffffc9000314f688
R13: 0000000000000215 R14: 0000000000000003 R15: 000020000004f000
 fault_signal_pending include/linux/sched/signal.h:408 [inline]
 do_user_addr_fault+0x750/0xc80 arch/x86/mm/fault.c:1359
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:206
Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 01 ca c3 90 90 90 90 90 90 90 0f 01 cb 83 fa 40 0f 82 70 ff ff ff 89 d1 <f3> a4 31 c0 0f 01 ca c3 90 90 90 90 90 90 90 90 90 90 89 d1 83 f8
RSP: 0018:ffffc9000314f738 EFLAGS: 00050206
RAX: ffffffff83d89f01 RBX: 00000000000101d0 RCX: 0000000000003194
RDX: 00000000000101d0 RSI: ffff88804728d124 RDI: 000020000004f000
RBP: ffffc9000314f898 R08: dffffc0000000000 R09: ffffed1008e52057
R10: 0000000000000000 R11: 0000000000002030 R12: ffff8880472800e8
R13: dffffc00000000ff R14: 0000200000041fc4 R15: 0000000000041bc4
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 copyout lib/iov_iter.c:157 [inline]
 _copy_to_iter+0x314/0x1160 lib/iov_iter.c:669
 __skb_datagram_iter+0xde/0x740 net/core/datagram.c:425
 skb_copy_datagram_iter+0xad/0x1f0 net/core/datagram.c:541
 skb_copy_datagram_msg include/linux/skbuff.h:3773 [inline]
 tipc_recvstream+0x727/0xe70 net/tipc/socket.c:2071
 ____sys_recvmsg+0x291/0x580 net/socket.c:-1
 ___sys_recvmsg+0x1af/0x4f0 net/socket.c:2707
 __sys_recvmsg net/socket.c:2737 [inline]
 __do_sys_recvmsg net/socket.c:2747 [inline]
 __se_sys_recvmsg net/socket.c:2744 [inline]
 __x64_sys_recvmsg+0x1dd/0x2a0 net/socket.c:2744
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fca3031e749
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:00007fca2e564038 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007fca30575090 RCX: 00007fca3031e749
RDX: 0000000000001f00 RSI: 0000200000000500 RDI: 0000000000000009
RBP: 00007fca303a2f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fca30575128 R14: 00007fca30575090 R15: 00007ffc5ffce248
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/17 16:28 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_recvmsg
2025/09/18 07:13 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_recvmsg
2025/08/10 06:15 linux-5.15.y c79648372d02 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_recvmsg
* Struck through repros no longer work on HEAD.