net: bpf: be friendly to kmemcheck

Reported by Mikulas Patocka, kmemcheck currently barks out a
false positive since we don't have special kmemcheck annotation
for bitfields used in bpf_prog structure.

We currently have jited:1, len:31 and thus when accessing len
while CONFIG_KMEMCHECK enabled, kmemcheck throws a warning that
we're reading uninitialized memory.

As we don't need the whole bit universe for pages member, we
can just split it to u16 and use a bool flag for jited instead
of a bitfield.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 2d1a5b9..6b45f64 100644 (file)
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -933,7 +933,7 @@ void bpf_jit_compile(struct bpf_prog *fp)
 
        set_memory_ro((unsigned long)header, header->pages);
        fp->bpf_func = (void *)ctx.target;
-       fp->jited = 1;
+       fp->jited = true;
 out:
        kfree(ctx.offsets);
        return;

diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index cfa83cf..0e97ccd 100644 (file)
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -1417,7 +1417,7 @@ void bpf_jit_compile(struct bpf_prog *fp)
                bpf_jit_dump(fp->len, alloc_size, 2, ctx.target);
 
        fp->bpf_func = (void *)ctx.target;
-       fp->jited = 1;
+       fp->jited = true;
 
 out:
        kfree(ctx.offsets);

diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 40c53ff..cbae2df 100644 (file)
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -686,7 +686,7 @@ void bpf_jit_compile(struct bpf_prog *fp)
                ((u64 *)image)[0] = (u64)code_base;
                ((u64 *)image)[1] = local_paca->kernel_toc;
                fp->bpf_func = (void *)image;
-               fp->jited = 1;
+               fp->jited = true;
        }
 out:
        kfree(addrs);

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index b734f97..555f5c7 100644 (file)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -842,7 +842,7 @@ void bpf_jit_compile(struct bpf_prog *fp)
        if (jit.start) {
                set_memory_ro((unsigned long)header, header->pages);
                fp->bpf_func = (void *) jit.start;
-               fp->jited = 1;
+               fp->jited = true;
        }
 out:
        kfree(addrs);

diff --git a/arch/sparc/net/bpf_jit_comp.c b/arch/sparc/net/bpf_jit_comp.c
index f7a736b..b2ad9dc 100644 (file)
--- a/arch/sparc/net/bpf_jit_comp.c
+++ b/arch/sparc/net/bpf_jit_comp.c
@@ -801,7 +801,7 @@ cond_branch:                        f_offset = addrs[i + filter[i].jf];
        if (image) {
                bpf_flush_icache(image, image + proglen);
                fp->bpf_func = (void *)image;
-               fp->jited = 1;
+               fp->jited = true;
        }
 out:
        kfree(addrs);

diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 9de0b54..d56cd1f 100644 (file)
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -955,7 +955,7 @@ void bpf_int_jit_compile(struct bpf_prog *prog)
                bpf_flush_icache(header, image + proglen);
                set_memory_ro((unsigned long)header, header->pages);
                prog->bpf_func = (void *)image;
-               prog->jited = 1;
+               prog->jited = true;
        }
 out:
        kfree(addrs);

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 868764f..4b59ede 100644 (file)
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -300,9 +300,9 @@ struct bpf_work_struct {
 };
 
 struct bpf_prog {
-       u32                     pages;          /* Number of allocated pages */
-       u32                     jited:1,        /* Is our filter JIT'ed? */
-                               len:31;         /* Number of filter blocks */
+       u16                     pages;          /* Number of allocated pages */
+       bool                    jited;          /* Is our filter JIT'ed? */
+       u32                     len;            /* Number of filter blocks */
        struct sock_fprog_kern  *orig_prog;     /* Original BPF program */
        struct bpf_work_struct  *work;          /* Deferred free work struct */
        unsigned int            (*bpf_func)(const struct sk_buff *skb,

diff --git a/net/core/filter.c b/net/core/filter.c
index fa5b7d0..dfc716f 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -972,7 +972,7 @@ static struct bpf_prog *bpf_prepare_filter(struct bpf_prog *fp)
        int err;
 
        fp->bpf_func = NULL;
-       fp->jited = 0;
+       fp->jited = false;
 
        err = bpf_check_classic(fp->insns, fp->len);
        if (err) {