diff mbox series

libbpf: skip DWARF sections in linker sanity check

Message ID 20231219110324.8989-1-hi@alyssa.is (mailing list archive)
State Accepted
Commit a4897b87775c945902b9a2fae0ae06946f59541d
Delegated to: BPF
Headers show
Series libbpf: skip DWARF sections in linker sanity check | expand

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netdev/tree_selection success Not a local patch
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Commit Message

Alyssa Ross Dec. 19, 2023, 11:03 a.m. UTC 
clang can generate (with -g -Wa,--compress-debug-sections) 4-byte
aligned DWARF sections that declare themselves to be 8-byte aligned in
the section header.  Since DWARF sections are dropped during linking
anyway, just skip running the sanity checks on them.

Reported-by: Sergei Trofimovich <slyich@gmail.com>
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Closes: https://lore.kernel.org/bpf/ZXcFRJVKbKxtEL5t@nz.home/
Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
 tools/lib/bpf/linker.c | 3 +++
 1 file changed, 3 insertions(+)


base-commit: 733763285acfe8dffd6e39ad2ed3d1222b32a901

Comments

Daniel Borkmann Dec. 20, 2023, 3:28 p.m. UTC | #1 
On 12/19/23 12:03 PM, Alyssa Ross wrote:
> clang can generate (with -g -Wa,--compress-debug-sections) 4-byte
> aligned DWARF sections that declare themselves to be 8-byte aligned in
> the section header.  Since DWARF sections are dropped during linking
> anyway, just skip running the sanity checks on them.
> 
> Reported-by: Sergei Trofimovich <slyich@gmail.com>
> Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
> Closes: https://lore.kernel.org/bpf/ZXcFRJVKbKxtEL5t@nz.home/
> Signed-off-by: Alyssa Ross <hi@alyssa.is>

Looks reasonable to skip, thus:

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
patchwork-bot+netdevbpf@kernel.org Dec. 20, 2023, 11:40 p.m. UTC | #2 
Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Tue, 19 Dec 2023 12:03:24 +0100 you wrote:
> clang can generate (with -g -Wa,--compress-debug-sections) 4-byte
> aligned DWARF sections that declare themselves to be 8-byte aligned in
> the section header.  Since DWARF sections are dropped during linking
> anyway, just skip running the sanity checks on them.
> 
> Reported-by: Sergei Trofimovich <slyich@gmail.com>
> Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
> Closes: https://lore.kernel.org/bpf/ZXcFRJVKbKxtEL5t@nz.home/
> Signed-off-by: Alyssa Ross <hi@alyssa.is>
> 
> [...]

Here is the summary with links:
  - libbpf: skip DWARF sections in linker sanity check
    https://git.kernel.org/bpf/bpf-next/c/a4897b87775c

You are awesome, thank you!
diff mbox series

Patch

diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c
index 52a2901e8bd0..16bca56002ab 100644
--- a/tools/lib/bpf/linker.c
+++ b/tools/lib/bpf/linker.c
@@ -719,6 +719,9 @@  static int linker_sanity_check_elf(struct src_obj *obj)
 			return -EINVAL;
 		}
 
+		if (is_dwarf_sec_name(sec->sec_name))
+			continue;
+
 		if (sec->shdr->sh_addralign && !is_pow_of_2(sec->shdr->sh_addralign)) {
 			pr_warn("ELF section #%zu alignment %llu is non pow-of-2 alignment in %s\n",
 				sec->sec_idx, (long long unsigned)sec->shdr->sh_addralign,