From: Hengqi Chen <hengqi.chen@gmail.com>
To: chenhuacai@kernel.org, yangtiezhu@loongson.cn,
jianghaoran@kylinos.cn, duanchenghao@kylinos.cn, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev,
vincent.mc.li@gmail.com
Cc: bpf@vger.kernel.org, loongarch@lists.linux.dev,
Hengqi Chen <hengqi.chen@gmail.com>
Subject: [PATCH 3/3] LoongArch: BPF: No support of struct argument in trampoline programs
Date: Thu, 21 Aug 2025 09:10:03 +0000 [thread overview]
Message-ID: <20250821091003.404870-4-hengqi.chen@gmail.com> (raw)
In-Reply-To: <20250821091003.404870-1-hengqi.chen@gmail.com>
The current implementation does not support struct argument.
This cause a oops when running bpf selftest:
$ ./test_progs -a tracing_struct
CPU -1 Unable to handle kernel paging request at virtual address 0000000000000018, era == 90000000845659f4, ra == 90000000845659e8
Oops[#1]:
CPU -1 Unable to handle kernel paging request at virtual address 0000000000000018, era == 9000000085bef268, ra == 90000000844f3938
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...0: (19 ticks this GP) idle=1094/1/0x4000000000000000 softirq=1380/1382 fqs=801
rcu: (detected by 0, t=5252 jiffies, g=1197, q=52 ncpus=4)
Sending NMI from CPU 0 to CPUs 1:
rcu: rcu_preempt kthread starved for 2495 jiffies! g1197 f0x0 RCU_GP_DOING_FQS(6) ->state=0x0 ->cpu=2
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:I stack:0 pid:15 tgid:15 ppid:2 task_flags:0x208040 flags:0x00000800
Stack : 9000000100423e80 0000000000000402 0000000000000010 90000001003b0680
9000000085d88000 0000000000000000 0000000000000040 9000000087159350
9000000085c2b9b0 0000000000000001 900000008704a000 0000000000000005
00000000ffff355b 00000000ffff355b 0000000000000000 0000000000000004
9000000085d90510 0000000000000000 0000000000000002 7b5d998f8281e86e
00000000ffff355c 7b5d998f8281e86e 000000000000003f 9000000087159350
900000008715bf98 0000000000000005 9000000087036000 900000008704a000
9000000100407c98 90000001003aff80 900000008715c4c0 9000000085c2b9b0
00000000ffff355b 9000000085c33d3c 00000000000000b4 0000000000000000
9000000007002150 00000000ffff355b 9000000084615480 0000000007000002
...
Call Trace:
[<9000000085c2a868>] __schedule+0x410/0x1520
[<9000000085c2b9ac>] schedule+0x34/0x190
[<9000000085c33d38>] schedule_timeout+0x98/0x140
[<90000000845e9120>] rcu_gp_fqs_loop+0x5f8/0x868
[<90000000845ed538>] rcu_gp_kthread+0x260/0x2e0
[<900000008454e8a4>] kthread+0x144/0x238
[<9000000085c26b60>] ret_from_kernel_thread+0x28/0xc8
[<90000000844f20e4>] ret_from_kernel_thread_asm+0xc/0x88
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 2:
NMI backtrace for cpu 2 skipped: idling at idle_exit+0x0/0x4
Reject it for now.
Fixes: f9b6b41f0cf3 ("LoongArch: BPF: Add basic bpf trampoline support")
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
---
arch/loongarch/net/bpf_jit.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
index 6754e5231ece..a87f51f5b708 100644
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -1516,6 +1516,12 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i
if (m->nr_args > LOONGARCH_MAX_REG_ARGS)
return -ENOTSUPP;
+ /* don't support struct argument */
+ for (i = 0; i < m->nr_args; i++) {
+ if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
+ return -ENOTSUPP;
+ }
+
if (flags & (BPF_TRAMP_F_ORIG_STACK | BPF_TRAMP_F_SHARE_IPMODIFY))
return -ENOTSUPP;
--
2.43.5
next prev parent reply other threads:[~2025-08-21 12:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-21 9:10 [PATCH 0/3] LoongArch: Fix BPF trampoline related issues Hengqi Chen
2025-08-21 9:10 ` [PATCH 1/3] LoongArch: BPF: Remove duplicated flags check Hengqi Chen
2025-08-21 13:48 ` Tiezhu Yang
2025-08-21 9:10 ` [PATCH 2/3] LoongArch: BPF: Sign extend struct ops return values properly Hengqi Chen
2025-08-21 13:52 ` Tiezhu Yang
2025-08-21 9:10 ` Hengqi Chen [this message]
2025-08-21 13:57 ` [PATCH 3/3] LoongArch: BPF: No support of struct argument in trampoline programs Tiezhu Yang
2025-08-25 2:11 ` [PATCH 0/3] LoongArch: Fix BPF trampoline related issues Vincent Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250821091003.404870-4-hengqi.chen@gmail.com \
--to=hengqi.chen@gmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=chenhuacai@kernel.org \
--cc=daniel@iogearbox.net \
--cc=duanchenghao@kylinos.cn \
--cc=jianghaoran@kylinos.cn \
--cc=loongarch@lists.linux.dev \
--cc=martin.lau@linux.dev \
--cc=vincent.mc.li@gmail.com \
--cc=yangtiezhu@loongson.cn \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).