Messages in this thread Patch in this message | | | From | Tiezhu Yang <> | Subject | [PATCH bpf-next 3/3] bpf: Print some info if disable bpf_jit_enable failed | Date | Mon, 9 May 2022 14:57:55 +0800 |
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A user told me that bpf_jit_enable can be disabled on one system, but he failed to disable bpf_jit_enable on the other system:
# echo 0 > /proc/sys/net/core/bpf_jit_enable bash: echo: write error: Invalid argument
No useful info is available through the dmesg log, a quick analysis shows that the issue is related with CONFIG_BPF_JIT_ALWAYS_ON.
When CONFIG_BPF_JIT_ALWAYS_ON is enabled, bpf_jit_enable is permanently set to 1 and setting any other value than that will return failure.
It is better to print some info to tell the user if disable bpf_jit_enable failed.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- net/core/sysctl_net_core.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 059352b..f8a1d450 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -266,6 +266,8 @@ static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write, loff_t *ppos) { int ret, jit_enable = *(int *)table->data; + int min = *(int *)table->extra1; + int max = *(int *)table->extra2; struct ctl_table tmp = *table; tmp.data = &jit_enable; @@ -280,6 +282,10 @@ static int proc_dointvec_minmax_bpf_enable(struct ctl_table *table, int write, ret = -EPERM; } } + + if (write && ret && min == max) + pr_info("CONFIG_BPF_JIT_ALWAYS_ON is enabled, bpf_jit_enable is permanently set to 1.\n"); + return ret; } -- 2.1.0
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