The attached program, along with the attached bpf_cubic.o eBPF binary, uses bpftool to install a tcp_ca struct ops, creates a tcp connection, and then unregisters the struct ops while the tcp connection is still active. On my 6.13.0 system this causes a kernel fault due to tcp_tso_segs() calling through a de-allocated struct tcp_congestion_ops. bpf_cubic.o came from https://github.com/aroodgar/bpf-tcp-congestion-control-algorithm Linux ubuntu66 6.13.0-rc1-00337-g7503345ac5f5 #11 SMP Sun Dec 8 08:37:57 EST 2024 x86_64 x86_64 x86_64 GNU/Linux Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] SMP DEBUG_PAGEALLOC PTI CPU: 6 UID: 0 PID: 1594 Comm: a.out Not tainted 6.13.0-rc1-00337-g7503345ac5f5 #11 Hardware name: FreeBSD BHYVE/BHYVE, BIOS 14.0 10/17/2021 RIP: 0010:__x86_indirect_thunk_array+0xa/0x20 Code: 66 0f 1f 00 31 ff e9 15 70 d6 fe cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc e8 01 00 00 00 cc 48 89 04 24 <c3> cc cc cc cc 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 RSP: 0018:ffffc90002037c60 EFLAGS: 00010202 RAX: 6b6b6b6b6b6b6b6b RBX: ffff88810afc0b00 RCX: 0000000000000018 RDX: 00000000077b668a RSI: 0000000000008000 RDI: ffff88810afc0b00 RBP: 0000000000008000 R08: 0000000000000000 R09: 0000000000008000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000008000 R14: 0000000000000000 R15: ffffffff842f6140 FS: 00007f5457b84740(0000) GS:ffff88842db80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5457d8c710 CR3: 000000011b4b8005 CR4: 00000000003706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? die_addr+0x31/0x80 ? exc_general_protection+0x1b4/0x3c0 ? asm_exc_general_protection+0x26/0x30 ? __x86_indirect_thunk_array+0xa/0x20 ? tcp_tso_segs+0x1c/0x90 ? tcp_write_xmit+0x74/0x1840 ? __mod_memcg_state+0x91/0x190 ? __tcp_push_pending_frames+0x31/0xc0 ? tcp_sendmsg_locked+0xafc/0xd10 ? tcp_sendmsg+0x26/0x40 ? sock_write_iter+0x167/0x1a0 ? vfs_write+0x35d/0x400 ? ksys_write+0xc6/0xe0 ? do_syscall_64+0x3f/0xd0 ? entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> Robert Morris rtm@xxxxxxx
Attachment:
tcpbpf12a.c
Description: Binary data
Attachment:
bpf_cubic.o
Description: Binary data
