kernel.git/tools/bpf/resolve_btfids, branch linux-5.13.y

bpf: Fix libelf endian handling in resolv_btfids

2021-07-14T15:07:07Z

[ Upstream commit 61e8aeda9398925f8c6fc290585bdd9727d154c4 ] The vmlinux ".BTF_ids" ELF section is declared in btf_ids.h to hold a list of zero-filled BTF IDs, which is then patched at link-time with correct values by resolv_btfids. The section is flagged as "allocable" to preclude compression, but notably the section contents (BTF IDs) are untyped. When patching the BTF IDs, resolve_btfids writes in host-native endianness and relies on libelf for any required translation on reading and updating vmlinux. However, since the type of the .BTF_ids section content defaults to ELF_T_BYTE (i.e. unsigned char), no translation occurs. This results in incorrect patched values when cross-compiling to non-native endianness, and can manifest as kernel Oops and test failures which are difficult to troubleshoot [1]. Explicitly set the type of patched data to ELF_T_WORD, the architecture- neutral ELF type corresponding to the u32 BTF IDs. This enables libelf to transparently perform any needed endian conversions. Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object") Signed-off-by: Tony Ambardar Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Cc: Frank Eigler Cc: Mark Wielaard Cc: Jiri Olsa Cc: Yonghong Song Link: https://lore.kernel.org/bpf/CAPGftE_eY-Zdi3wBcgDfkz_iOr1KF10n=9mJHm1_a_PykcsoeA@mail.gmail.com [1] Link: https://lore.kernel.org/bpf/20210618061404.818569-1-Tony.Ambardar@gmail.com Signed-off-by: Sasha Levin

tools/resolve_btfids: Fix warnings

2021-03-31T19:09:12Z

* make eprintf static, used only in main.c * initialize ret in eprintf * remove unused *tmp v3: * remove another err (Song Liu) v2: * remove unused 'int err = -1' Signed-off-by: Stanislav Fomichev Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20210329223143.3659983-1-sdf@google.com

tools/resolve_btfids: Fix build error with older host toolchains

2021-02-24T16:19:11Z

Older libelf.h and glibc elf.h might not yet define the ELF compression types. Checking and defining SHF_COMPRESSED fix the build error when compiling with older toolchains. Also, the tool resolve_btfids is compiled with host toolchain. The host toolchain is more likely to be older than the cross compile toolchain. Fixes: 51f6463aacfb ("tools/resolve_btfids: Fix sections with wrong alignment") Signed-off-by: Kun-Chuan Hsieh Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20210224052752.5284-1-jetswayss@gmail.com

tools/resolve_btfids: Add /libbpf to .gitignore

2021-02-12T21:08:26Z

This is what I see after compiling the kernel: # bpf-next...bpf-next/master ?? tools/bpf/resolve_btfids/libbpf/ Fixes: fc6b48f692f8 ("tools/resolve_btfids: Build libbpf and libsubcmd in separate directories") Signed-off-by: Stanislav Fomichev Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210212010053.668700-1-sdf@google.com

tools/resolve_btfids: Set srctree variable unconditionally

2021-02-09T05:21:39Z

We want this clean to be called from tree's root Makefile, which defines same srctree variable and that will screw the make setup. We actually do not use srctree being passed from outside, so we can solve this by setting current srctree value directly. Also changing the way how srctree is initialized as suggested by Andrri. Also root Makefile does not define the implicit RM variable, so adding RM initialization. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210205124020.683286-4-jolsa@kernel.org

tools/resolve_btfids: Check objects before removing

2021-02-09T05:21:39Z

We want this clean to be called from tree's root clean and that one is silent if there's nothing to clean. Adding check for all object to clean and display CLEAN messages only if there are objects to remove. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210205124020.683286-3-jolsa@kernel.org

tools/resolve_btfids: Build libbpf and libsubcmd in separate directories

2021-02-09T05:21:39Z

Setting up separate build directories for libbpf and libpsubcmd, so it's separated from other objects and we don't get them mixed in the future. It also simplifies cleaning, which is now simple rm -rf. Also there's no need for FEATURE-DUMP.libbpf and bpf_helper_defs.h files in .gitignore anymore. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210205124020.683286-2-jolsa@kernel.org

tools/resolve_btfids: Warn when having multiple IDs for single type

2021-01-06T02:11:55Z

The kernel image can contain multiple types (structs/unions) with the same name. This causes distinct type hierarchies in BTF data and makes resolve_btfids fail with error like: BTFIDS vmlinux FAILED unresolved symbol udp6_sock as reported by Qais Yousef [1]. This change adds warning when multiple types of the same name are detected: BTFIDS vmlinux WARN: multiple IDs found for 'file': 526, 113351 - using 526 WARN: multiple IDs found for 'sk_buff': 2744, 113958 - using 2744 We keep the lower ID for the given type instance and let the build continue. Also changing the 'nr' variable name to 'nr_types' to avoid confusion. [1] https://lore.kernel.org/lkml/20201229151352.6hzmjvu3qh6p2qgg@e107158-lin/ Signed-off-by: Jiri Olsa Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210105234219.970039-1-jolsa@kernel.org

tools/resolve_btfids: Fix some error messages

2020-12-03T18:25:47Z

Add missing newlines and fix polarity of strerror argument. Signed-off-by: Brendan Jackman Signed-off-by: Alexei Starovoitov Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20201203102234.648540-1-jackmanb@google.com

tools: Factor HOSTCC, HOSTLD, HOSTAR definitions

2020-11-11T20:18:22Z

Several Makefiles in tools/ need to define the host toolchain variables. Move their definition to tools/scripts/Makefile.include Signed-off-by: Jean-Philippe Brucker Signed-off-by: Andrii Nakryiko Acked-by: Jiri Olsa Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/bpf/20201110164310.2600671-2-jean-philippe@linaro.org