| Message ID | 20231018062234.20492-3-shung-hsi.yu@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | David Ahern |
| Headers | show |
| Series | Increase BPF verifier verbosity when in verbose mode | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On 10/18/23 12:22 AM, Shung-Hsi Yu wrote: > diff --git a/lib/bpf_libbpf.c b/lib/bpf_libbpf.c > index f678a710..08692d30 100644 > --- a/lib/bpf_libbpf.c > +++ b/lib/bpf_libbpf.c > @@ -285,11 +285,14 @@ static int load_bpf_object(struct bpf_cfg_in *cfg) > DECLARE_LIBBPF_OPTS(bpf_object_open_opts, open_opts, > .relaxed_maps = true, > .pin_root_path = root_path, > -#ifdef (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) > - .kernel_log_level = 1, > -#endif > ); > > +#if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) > + open_opts.kernel_log_level = 1; > + if (cfg->verbose) > + open_opts.kernel_log_level |= 2; > +#endif > + > obj = bpf_object__open_file(cfg->object, &open_opts); > if (libbpf_get_error(obj)) { > fprintf(stderr, "ERROR: opening BPF object file failed\n"); Why have the first patch if you redo the code here?
On Wed, Oct 18, 2023 at 08:35:30AM -0600, David Ahern wrote: > On 10/18/23 12:22 AM, Shung-Hsi Yu wrote: > > diff --git a/lib/bpf_libbpf.c b/lib/bpf_libbpf.c > > index f678a710..08692d30 100644 > > --- a/lib/bpf_libbpf.c > > +++ b/lib/bpf_libbpf.c > > @@ -285,11 +285,14 @@ static int load_bpf_object(struct bpf_cfg_in *cfg) > > DECLARE_LIBBPF_OPTS(bpf_object_open_opts, open_opts, > > .relaxed_maps = true, > > .pin_root_path = root_path, > > -#ifdef (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) > > - .kernel_log_level = 1, > > -#endif > > ); > > > > +#if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) > > + open_opts.kernel_log_level = 1; > > + if (cfg->verbose) > > + open_opts.kernel_log_level |= 2; > > +#endif > > + > > obj = bpf_object__open_file(cfg->object, &open_opts); > > if (libbpf_get_error(obj)) { > > fprintf(stderr, "ERROR: opening BPF object file failed\n"); > > Why have the first patch if you redo the code here? Ah, good point. I was trying to separate out libbpf-related changes from verbosity-increasing changes, hence the first patch. And there I add the .kernel_log_level field within DECLARE_LIBBPF_OPTS() because that seems to be how it's usually done. In the second patch I tried to make log-level changes consistent, having them all done with `|= 2`, which isn't possible within DECLARE_LIBBPF_OPTS(). Maybe I should have just have `open_opts.kernel_log_level = 1;` outside of DECLARE_LIBBPF_OPTS() in the first patch to begin with. +#if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) + open_opts.kernel_log_level = 1; +#endif Followed by #if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) open_opts.kernel_log_level = 1; + if (cfg->verbose) + open_opts.kernel_log_level |= 2; #endif Would be better than DECLARE_LIBBPF_OPTS(bpf_object_open_opts, open_opts, .relaxed_maps = true, .pin_root_path = root_path, +#ifdef (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) + .kernel_log_level = 1, +#endif ); Followed by DECLARE_LIBBPF_OPTS(bpf_object_open_opts, open_opts, .relaxed_maps = true, .pin_root_path = root_path, #ifdef (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) - .kernel_log_level = 1, + .kernel_log_level = cfg->verbose ? (2 | 1) : 1, #endif ); I suppose. What do you think?
On 10/18/23 7:18 PM, Shung-Hsi Yu wrote: > Ah, good point. I was trying to separate out libbpf-related changes from > verbosity-increasing changes, hence the first patch. And there I add the > .kernel_log_level field within DECLARE_LIBBPF_OPTS() because that seems to > be how it's usually done. > > In the second patch I tried to make log-level changes consistent, having > them all done with `|= 2`, which isn't possible within > DECLARE_LIBBPF_OPTS(). > > Maybe I should have just have `open_opts.kernel_log_level = 1;` outside of > DECLARE_LIBBPF_OPTS() in the first patch to begin with. > > +#if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) > + open_opts.kernel_log_level = 1; > +#endif > > Followed by > > #if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) > open_opts.kernel_log_level = 1; > + if (cfg->verbose) > + open_opts.kernel_log_level |= 2; > #endif > that is less confusing for a patch sequence.
On Thu, Oct 19, 2023 at 01:44:34PM -0600, David Ahern wrote: > On 10/18/23 7:18 PM, Shung-Hsi Yu wrote: > > Ah, good point. I was trying to separate out libbpf-related changes from > > verbosity-increasing changes, hence the first patch. And there I add the > > .kernel_log_level field within DECLARE_LIBBPF_OPTS() because that seems to > > be how it's usually done. > > > > In the second patch I tried to make log-level changes consistent, having > > them all done with `|= 2`, which isn't possible within > > DECLARE_LIBBPF_OPTS(). > > > > Maybe I should have just have `open_opts.kernel_log_level = 1;` outside of > > DECLARE_LIBBPF_OPTS() in the first patch to begin with. > > > > +#if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) > > + open_opts.kernel_log_level = 1; > > +#endif > > > > Followed by > > > > #if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) > > open_opts.kernel_log_level = 1; > > + if (cfg->verbose) > > + open_opts.kernel_log_level |= 2; > > #endif > > > > that is less confusing for a patch sequence. Thanks for the review. Will do this in v2.
diff --git a/include/bpf_util.h b/include/bpf_util.h index 1c924f50..8951a5e8 100644 --- a/include/bpf_util.h +++ b/include/bpf_util.h @@ -273,10 +273,10 @@ void bpf_print_ops(struct rtattr *bpf_ops, __u16 len); int bpf_prog_load_dev(enum bpf_prog_type type, const struct bpf_insn *insns, size_t size_insns, const char *license, __u32 ifindex, - char *log, size_t size_log); + char *log, size_t size_log, bool verbose); int bpf_program_load(enum bpf_prog_type type, const struct bpf_insn *insns, size_t size_insns, const char *license, char *log, - size_t size_log); + size_t size_log, bool verbose); int bpf_prog_attach_fd(int prog_fd, int target_fd, enum bpf_attach_type type); int bpf_prog_detach_fd(int target_fd, enum bpf_attach_type type); diff --git a/ip/ipvrf.c b/ip/ipvrf.c index 12beaec3..e7c702ab 100644 --- a/ip/ipvrf.c +++ b/ip/ipvrf.c @@ -253,7 +253,8 @@ static int prog_load(int idx) }; return bpf_program_load(BPF_PROG_TYPE_CGROUP_SOCK, prog, sizeof(prog), - "GPL", bpf_log_buf, sizeof(bpf_log_buf)); + "GPL", bpf_log_buf, sizeof(bpf_log_buf), + false); } static int vrf_configure_cgroup(const char *path, int ifindex) diff --git a/lib/bpf_legacy.c b/lib/bpf_legacy.c index 3542b12f..844974e9 100644 --- a/lib/bpf_legacy.c +++ b/lib/bpf_legacy.c @@ -1098,7 +1098,7 @@ int bpf_prog_detach_fd(int target_fd, enum bpf_attach_type type) int bpf_prog_load_dev(enum bpf_prog_type type, const struct bpf_insn *insns, size_t size_insns, const char *license, __u32 ifindex, - char *log, size_t size_log) + char *log, size_t size_log, bool verbose) { union bpf_attr attr = {}; @@ -1112,6 +1112,8 @@ int bpf_prog_load_dev(enum bpf_prog_type type, const struct bpf_insn *insns, attr.log_buf = bpf_ptr_to_u64(log); attr.log_size = size_log; attr.log_level = 1; + if (verbose) + attr.log_level |= 2; } return bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); @@ -1119,9 +1121,9 @@ int bpf_prog_load_dev(enum bpf_prog_type type, const struct bpf_insn *insns, int bpf_program_load(enum bpf_prog_type type, const struct bpf_insn *insns, size_t size_insns, const char *license, char *log, - size_t size_log) + size_t size_log, bool verbose) { - return bpf_prog_load_dev(type, insns, size_insns, license, 0, log, size_log); + return bpf_prog_load_dev(type, insns, size_insns, license, 0, log, size_log, verbose); } #ifdef HAVE_ELF @@ -1543,7 +1545,7 @@ retry: errno = 0; fd = bpf_prog_load_dev(prog->type, prog->insns, prog->size, prog->license, ctx->ifindex, - ctx->log, ctx->log_size); + ctx->log, ctx->log_size, ctx->verbose); if (fd < 0 || ctx->verbose) { /* The verifier log is pretty chatty, sometimes so chatty * on larger programs, that we could fail to dump everything diff --git a/lib/bpf_libbpf.c b/lib/bpf_libbpf.c index f678a710..08692d30 100644 --- a/lib/bpf_libbpf.c +++ b/lib/bpf_libbpf.c @@ -285,11 +285,14 @@ static int load_bpf_object(struct bpf_cfg_in *cfg) DECLARE_LIBBPF_OPTS(bpf_object_open_opts, open_opts, .relaxed_maps = true, .pin_root_path = root_path, -#ifdef (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) - .kernel_log_level = 1, -#endif ); +#if (LIBBPF_MAJOR_VERSION > 0) || (LIBBPF_MINOR_VERSION >= 7) + open_opts.kernel_log_level = 1; + if (cfg->verbose) + open_opts.kernel_log_level |= 2; +#endif + obj = bpf_object__open_file(cfg->object, &open_opts); if (libbpf_get_error(obj)) { fprintf(stderr, "ERROR: opening BPF object file failed\n");
The BPF verifier allows setting a higher verbosity level, which is helpful when it comes to debugging verifier issue, specially when used to BPF program that loads successfully (but should not have passed the verifier in the first place). Increase the BPF verifier log level in when in verbose mode to help with such cases. Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> --- include/bpf_util.h | 4 ++-- ip/ipvrf.c | 3 ++- lib/bpf_legacy.c | 10 ++++++---- lib/bpf_libbpf.c | 9 ++++++--- 4 files changed, 16 insertions(+), 10 deletions(-)