* [PATCH bpf-next] bpf: fix bpf_prog_pack build for ppc64_defconfig
@ 2022-02-11 1:49 Song Liu
2022-02-11 23:54 ` Jakub Kicinski
0 siblings, 1 reply; 3+ messages in thread
From: Song Liu @ 2022-02-11 1:49 UTC (permalink / raw)
To: bpf, netdev; +Cc: ast, daniel, andrii, kernel-team, sfr, Song Liu
bpf_prog_pack causes build error with powerpc ppc64_defconfig:
kernel/bpf/core.c:830:23: error: variably modified 'bitmap' at file scope
830 | unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
| ^~~~~~
Fix it by turning bitmap into a 0-length array.
Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Song Liu <song@kernel.org>
---
kernel/bpf/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 42d96549a804..44623c9b5bb1 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -827,7 +827,7 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
struct bpf_prog_pack {
struct list_head list;
void *ptr;
- unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
+ unsigned long bitmap[];
};
#define BPF_PROG_MAX_PACK_PROG_SIZE BPF_PROG_PACK_SIZE
@@ -840,7 +840,7 @@ static struct bpf_prog_pack *alloc_new_pack(void)
{
struct bpf_prog_pack *pack;
- pack = kzalloc(sizeof(*pack), GFP_KERNEL);
+ pack = kzalloc(sizeof(*pack) + BITS_TO_BYTES(BPF_PROG_CHUNK_COUNT), GFP_KERNEL);
if (!pack)
return NULL;
pack->ptr = module_alloc(BPF_PROG_PACK_SIZE);
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next] bpf: fix bpf_prog_pack build for ppc64_defconfig
2022-02-11 1:49 [PATCH bpf-next] bpf: fix bpf_prog_pack build for ppc64_defconfig Song Liu
@ 2022-02-11 23:54 ` Jakub Kicinski
2022-02-12 1:23 ` Song Liu
0 siblings, 1 reply; 3+ messages in thread
From: Jakub Kicinski @ 2022-02-11 23:54 UTC (permalink / raw)
To: Song Liu; +Cc: bpf, netdev, ast, daniel, andrii, kernel-team, sfr
On Thu, 10 Feb 2022 17:49:15 -0800 Song Liu wrote:
> bpf_prog_pack causes build error with powerpc ppc64_defconfig:
>
> kernel/bpf/core.c:830:23: error: variably modified 'bitmap' at file scope
> 830 | unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
> | ^~~~~~
No idea what this error means but...
> Fix it by turning bitmap into a 0-length array.
>
> Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator")
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Song Liu <song@kernel.org>
> ---
> kernel/bpf/core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index 42d96549a804..44623c9b5bb1 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -827,7 +827,7 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
> struct bpf_prog_pack {
> struct list_head list;
> void *ptr;
> - unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
> + unsigned long bitmap[];
This is really asking to be DECLARE_BITMAP(), does that fix the issue?
> };
>
> #define BPF_PROG_MAX_PACK_PROG_SIZE BPF_PROG_PACK_SIZE
> @@ -840,7 +840,7 @@ static struct bpf_prog_pack *alloc_new_pack(void)
> {
> struct bpf_prog_pack *pack;
>
> - pack = kzalloc(sizeof(*pack), GFP_KERNEL);
> + pack = kzalloc(sizeof(*pack) + BITS_TO_BYTES(BPF_PROG_CHUNK_COUNT), GFP_KERNEL);
Otherwise you may want to use struct_size(pack, bitmap, BITS...).
One of the bots will soon send us a patch to do that.
> if (!pack)
> return NULL;
> pack->ptr = module_alloc(BPF_PROG_PACK_SIZE);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next] bpf: fix bpf_prog_pack build for ppc64_defconfig
2022-02-11 23:54 ` Jakub Kicinski
@ 2022-02-12 1:23 ` Song Liu
0 siblings, 0 replies; 3+ messages in thread
From: Song Liu @ 2022-02-12 1:23 UTC (permalink / raw)
To: Jakub Kicinski
Cc: Song Liu, bpf, netdev, ast, daniel, andrii, Kernel Team, sfr
> On Feb 11, 2022, at 3:54 PM, Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Thu, 10 Feb 2022 17:49:15 -0800 Song Liu wrote:
>> bpf_prog_pack causes build error with powerpc ppc64_defconfig:
>>
>> kernel/bpf/core.c:830:23: error: variably modified 'bitmap' at file scope
>> 830 | unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
>> | ^~~~~~
>
> No idea what this error means but...
v2 (which has applied to bpf-next) has more information about this.
Basically, BPF_PROG_CHUNK_COUNT contains a global variable for ppc.
>
>> Fix it by turning bitmap into a 0-length array.
>>
>> Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator")
>> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
>> Signed-off-by: Song Liu <song@kernel.org>
>> ---
>> kernel/bpf/core.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
>> index 42d96549a804..44623c9b5bb1 100644
>> --- a/kernel/bpf/core.c
>> +++ b/kernel/bpf/core.c
>> @@ -827,7 +827,7 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
>> struct bpf_prog_pack {
>> struct list_head list;
>> void *ptr;
>> - unsigned long bitmap[BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)];
>> + unsigned long bitmap[];
>
> This is really asking to be DECLARE_BITMAP(), does that fix the issue?
I am afraid DECLARE_BITMAP() will hit the same error here.
>
>> };
>>
>> #define BPF_PROG_MAX_PACK_PROG_SIZE BPF_PROG_PACK_SIZE
>> @@ -840,7 +840,7 @@ static struct bpf_prog_pack *alloc_new_pack(void)
>> {
>> struct bpf_prog_pack *pack;
>>
>> - pack = kzalloc(sizeof(*pack), GFP_KERNEL);
>> + pack = kzalloc(sizeof(*pack) + BITS_TO_BYTES(BPF_PROG_CHUNK_COUNT), GFP_KERNEL);
>
> Otherwise you may want to use struct_size(pack, bitmap, BITS...).
> One of the bots will soon send us a patch to do that.
Since v2 has applied to bpf-next, I will send another follow-up patch to
use struct_size, unless some bot get it first.
Thanks,
Song
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-02-12 1:23 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-11 1:49 [PATCH bpf-next] bpf: fix bpf_prog_pack build for ppc64_defconfig Song Liu
2022-02-11 23:54 ` Jakub Kicinski
2022-02-12 1:23 ` Song Liu
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).