| Message ID | 20220211014915.2403508-1-song@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] bpf: fix bpf_prog_pack build for ppc64_defconfig | expand |
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);
> 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
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);
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(-)