Hi,
On 3/10/2022 7:22 AM, Alexei Starovoitov wrote:
> On Wed, Mar 09, 2022 at 08:33:20PM +0800, Hou Tao wrote:
>> It is the bpf_jit_harden counterpart to commit 60b58afc96c9 ("bpf: fix
>> net.core.bpf_jit_enable race"). bpf_jit_harden will be tested twice
>> for each subprog if there are subprogs in bpf program and constant
>> blinding may increase the length of program, so when running
>> "./test_progs -t subprogs" and toggling bpf_jit_harden between 0 and 2,
>> jit_subprogs may fail because constant blinding increases the length
>> of subprog instructions during extra passs.
>>
>> So cache the value of bpf_jit_blinding_enabled() during program
>> allocation, and use the cached value during constant blinding, subprog
>> JITing and args tracking of tail call.
> Looks like this patch alone is enough.
> With race fixed. Patches 1 and 2 are no longer necessary, right?
Yes and no. With patch 3 applied, the problems described in patch 1 and patch 2
are gone, but it may recur due to other issue in JIT. So I post these two patch
together and hope these fixes can also be merged.
> .
