On Tue, Jun 25, 2024 at 10:25 AM Geliang Tang <geliang@xxxxxxxxxx> wrote:
>
> From: Geliang Tang <tanggeliang@xxxxxxxxxx>
>
> Run the following BPF selftests on Loongarch:
>
> ./test_progs -t sockmap_basic
>
> A Kernel panic occurs:
>
> '''
> Oops[#1]:
> CPU: 22 PID: 2824 Comm: test_progs Tainted: G OE 6.10.0-rc2+ #18
> Hardware name: LOONGSON Dabieshan/Loongson-TC542F0, BIOS Loongson-UDK2018-V4.0.11
> pc 9000000004162774 ra 90000000048bf6c0 tp 90001000aa16c000 sp 90001000aa16fb90
> a0 0000000000000000 a1 0000000000000000 a2 0000000000000000 a3 90001000aa16fd70
> a4 0000000000000800 a5 0000000000000000 a6 000055557b63aae8 a7 00000000000000cf
> t0 0000000000000000 t1 0000000000004000 t2 0000000000000048 t3 0000000000000000
> t4 0000000000000001 t5 0000000000000002 t6 0000000000000001 t7 0000000000000002
> t8 0000000000000018 u0 9000000004856150 s9 0000000000000000 s0 0000000000000000
> s1 0000000000000000 s2 90001000aa16fd70 s3 0000000000000000 s4 0000000000000000
> s5 0000000000004000 s6 900010009284dc00 s7 0000000000000001 s8 900010009284dc00
> ra: 90000000048bf6c0 sk_msg_recvmsg+0x120/0x560
> ERA: 9000000004162774 copy_page_to_iter+0x74/0x1c0
> CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
> PRMD: 0000000c (PPLV0 +PIE +PWE)
> EUEN: 00000007 (+FPE +SXE +ASXE -BTE)
> ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
> ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)
> BADV: 0000000000000040
> PRID: 0014c011 (Loongson-64bit, Loongson-3C5000)
> Modules linked in: bpf_testmod(OE) xt_CHECKSUM xt_MASQUERADE xt_conntrack
> Process test_progs (pid: 2824, threadinfo=0000000000863a31, task=000000001cba0874)
> Stack : 0000000000000001 fffffffffffffffc 0000000000000000 0000000000000000
> 0000000000000018 0000000000000000 0000000000000000 90000000048bf6c0
> 90000000052cd638 90001000aa16fd70 900010008bf51580 900010009284f000
> 90000000049f2b90 900010009284f188 900010009284f178 90001000861d4780
> 9000100084dccd00 0000000000000800 0000000000000007 fffffffffffffff2
> 000000000453e92f 90000000049aae34 90001000aa16fd60 900010009284f000
> 0000000000000000 0000000000000000 900010008bf51580 90000000049f2b90
> 0000000000000001 0000000000000000 9000100084dc3a10 900010009284f1ac
> 90001000aa16fd40 0000555559953278 0000000000000001 0000000000000000
> 90001000aa16fdc8 9000000005a5a000 90001000861d4780 0000000000000800
> ...
> Call Trace:
> [<9000000004162774>] copy_page_to_iter+0x74/0x1c0
> [<90000000048bf6c0>] sk_msg_recvmsg+0x120/0x560
> [<90000000049f2b90>] tcp_bpf_recvmsg_parser+0x170/0x4e0
> [<90000000049aae34>] inet_recvmsg+0x54/0x100
> [<900000000481ad5c>] sock_recvmsg+0x7c/0xe0
> [<900000000481e1a8>] __sys_recvfrom+0x108/0x1c0
> [<900000000481e27c>] sys_recvfrom+0x1c/0x40
> [<9000000004c076ec>] do_syscall+0x8c/0xc0
> [<9000000003731da4>] handle_syscall+0xc4/0x160
>
> Code: 0010b09b 440125a0 0011df8d <28c10364> 0012b70c 00133305 0013b1ac 0010dc84 00151585
>
> ---[ end trace 0000000000000000 ]---
> Kernel panic - not syncing: Fatal exception
> Kernel relocated by 0x3510000
> .text @ 0x9000000003710000
> .data @ 0x9000000004d70000
> .bss @ 0x9000000006469400
> ---[ end Kernel panic - not syncing: Fatal exception ]---
> '''
>
> This is because "sg_page(sge)" is NULL in that case. This patch adds null
> check for it in sk_msg_recvmsg() to fix this error.
>
> Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
> Signed-off-by: Geliang Tang <tanggeliang@xxxxxxxxxx>
> ---
> net/core/skmsg.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/core/skmsg.c b/net/core/skmsg.c
> index fd20aae30be2..bafcc1e2eadf 100644
> --- a/net/core/skmsg.c
> +++ b/net/core/skmsg.c
> @@ -432,6 +432,8 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
> sge = sk_msg_elem(msg_rx, i);
> copy = sge->length;
> page = sg_page(sge);
> + if (!page)
> + goto out;
> if (copied + copy > len)
> copy = len - copied;
> copy = copy_page_to_iter(page, sge->offset, copy, iter);
> --
> 2.43.0
>
This looks pretty much random to me.
Please find the root cause, instead of desperately trying to fix 'tests'.
