INFO: rcu detected stall in tcp

ID	Workflow	Result	Correct	Bug	Created	Started	Finished	Revision	Error
26399bb1-7100-4bd0-b5e5-835d20e3f646	assessment-security	DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌	❓	INFO: rcu detected stall in tcp_sendmsg	2026/05/16 09:02	2026/05/16 09:02	2026/05/16 09:30	bccc1e4cfc08abce15de8b74287eef494a3f6e5e

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8041/2:b..l rcu: (detected by 1, t=10502 jiffies, g=23201, q=4981 ncpus=2) task:syz.4.614 state:R running task stack:22912 pid:8041 tgid:8039 ppid:5824 task_flags:0x400140 flags:0x00080002 Call Trace: <TASK> context_switch kernel/sched/core.c:5387 [inline] __schedule+0x169e/0x54f0 kernel/sched/core.c:7188 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x730 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5895 Code: 42 d6 10 00 00 00 00 eb b5 e8 05 41 96 09 f7 c3 00 02 00 00 74 b9 65 48 8b 05 e5 fb d5 10 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 4a 05 9a 09 cc 48 8d 3d 32 d2 ef RSP: 0018:ffffc90005a17338 EFLAGS: 00000282 RAX: 715fa631dc9bcd00 RBX: 0000000000000283 RCX: 0000000000000046 RDX: 00000000c96dac20 RSI: ffffffff8d8b42f4 RDI: ffffffff8ba845e0 RBP: ffff8880278849f0 R08: ffffffff8b393780 R09: ffffffff8dfc8140 R10: 0000000000000000 R11: ffffed1003618ccc R12: 0000000000000004 R13: 0000000000000004 R14: ffff8880447ecb98 R15: ffff888027883d80 rt_spin_unlock+0x29/0x200 kernel/locking/spinlock_rt.c:80 spin_unlock include/linux/spinlock_rt.h:109 [inline] do_anonymous_page mm/memory.c:5417 [inline] do_pte_missing+0x2607/0x2950 mm/memory.c:4548 handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault mm/memory.c:6549 [inline] handle_mm_fault+0xdb5/0x14c0 mm/memory.c:6718 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:rep_movs_alternative+0x4a/0x90 arch/x86/lib/copy_user_64.S:74 Code: cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 73 e8 eb c5 <f3> a4 e9 7f 24 05 00 48 8b 06 48 89 07 48 8d 47 08 48 83 e0 f8 48 RSP: 0018:ffffc90005a177b8 EFLAGS: 00050202 RAX: 00007ffffffff001 RBX: ffff888034a48000 RCX: 0000000000002a4d RDX: 0000000000000001 RSI: 00002000006e5000 RDI: ffff888034a4c700 RBP: ffffc90005a17910 R08: ffff888034a4f14c R09: 1ffff11006949e29 R10: dffffc0000000000 R11: ffffed1006949e2a R12: ffffc90005a17db8 R13: 00002000006e0900 R14: 000000000000714d R15: 1ffff92000b42fb7 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline] copy_from_user_iter lib/iov_iter.c:67 [inline] iterate_ubuf include/linux/iov_iter.h:30 [inline] iterate_and_advance2 include/linux/iov_iter.h:302 [inline] iterate_and_advance include/linux/iov_iter.h:330 [inline] __copy_from_iter lib/iov_iter.c:261 [inline] _copy_from_iter+0x21b/0x1670 lib/iov_iter.c:272 copy_from_iter include/linux/uio.h:228 [inline] copy_from_iter_full include/linux/uio.h:245 [inline] skb_do_copy_data_nocache include/net/sock.h:2307 [inline] skb_copy_to_page_nocache include/net/sock.h:2333 [inline] tcp_sendmsg_locked+0x2127/0x5370 net/ipv4/tcp.c:1314 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1455 sock_sendmsg_nosec+0xf9/0x150 net/socket.c:797 __sock_sendmsg net/socket.c:812 [inline] __sys_sendto+0x402/0x590 net/socket.c:2280 __do_sys_sendto net/socket.c:2287 [inline] __se_sys_sendto net/socket.c:2283 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2283 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efff0abc819 RSP: 002b:00007effeed16028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007efff0d35fa0 RCX: 00007efff0abc819 RDX: 00000000ffffff5d RSI: 0000200000000900 RDI: 0000000000000004 RBP: 00007efff0b52c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000012 R11: 0000000000000246 R12: 0000000000000000 R13: 00007efff0d36038 R14: 00007efff0d35fa0 R15: 00007ffcb88046f8 </TASK>

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2026/04/21 21:56	linux-next	bee6ea30c487	0b6ab7ec	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci-upstream-linux-next-kasan-gce-root	INFO: rcu detected stall in tcp_sendmsg

Crashes (1):

Assets (help?)