kernel/linux.git/tools/lib/bpf/btf.c, branch v6.12.80

libbpf: Fix parsing of multi-split BTF

2025-12-18T12:54:53+00:00

[ Upstream commit 4f596acc260e691a2e348f64230392f3472feea3 ] When creating multi-split BTF we correctly set the start string offset to be the size of the base string section plus the base BTF start string offset; the latter is needed for multi-split BTF since the offset is non-zero there. Unfortunately the BTF parsing case needed that logic and it was missed. Fixes: 4e29128a9ace ("libbpf/btf: Fix string handling to support multi-split BTF") Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20251104203309.318429-2-alan.maguire@oracle.com Signed-off-by: Sasha Levin

libbpf: Add identical pointer detection to btf_dedup_is_equiv()

2025-06-27T10:11:32+00:00

[ Upstream commit 8e64c387c942229c551d0f23de4d9993d3a2acb6 ] Recently as a side-effect of commit ac053946f5c4 ("compiler.h: introduce TYPEOF_UNQUAL() macro") issues were observed in deduplication between modules and kernel BTF such that a large number of kernel types were not deduplicated so were found in module BTF (task_struct, bpf_prog etc). The root cause appeared to be a failure to dedup struct types, specifically those with members that were pointers with __percpu annotations. The issue in dedup is at the point that we are deduplicating structures, we have not yet deduplicated reference types like pointers. If multiple copies of a pointer point at the same (deduplicated) integer as in this case, we do not see them as identical. Special handling already exists to deal with structures and arrays, so add pointer handling here too. Reported-by: Alexei Starovoitov Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250429161042.2069678-1-alan.maguire@oracle.com Signed-off-by: Sasha Levin

libbpf/btf: Fix string handling to support multi-split BTF

2025-06-27T10:11:29+00:00

[ Upstream commit 4e29128a9acec2a622734844bedee013e2901bdf ] libbpf handling of split BTF has been written largely with the assumption that multiple splits are possible, i.e. split BTF on top of split BTF on top of base BTF. One area where this does not quite work is string handling in split BTF; the start string offset should be the base BTF string section length + the base BTF string offset. This worked in the past because for a single split BTF with base the start string offset was always 0. Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250519165935.261614-2-alan.maguire@oracle.com Signed-off-by: Sasha Levin

libbpf: Fix return zero when elf_begin failed

2025-02-08T08:57:34+00:00

[ Upstream commit 5436a54332c19df0acbef2b87cbf9f7cba56f2dd ] The error number of elf_begin is omitted when encapsulating the btf_find_elf_sections function. Fixes: c86f180ffc99 ("libbpf: Make btf_parse_elf process .BTF.base transparently") Signed-off-by: Pu Lehui Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250115100241.4171581-2-pulehui@huaweicloud.com Signed-off-by: Sasha Levin

libbpf: Fix some typos in comments

2024-09-09T23:05:40+00:00

Fix some spelling errors in the code comments of libbpf: betwen -> between paremeters -> parameters knowning -> knowing definiton -> definition compatiblity -> compatibility overriden -> overridden occured -> occurred proccess -> process managment -> management nessary -> necessary Signed-off-by: Yusheng Zheng Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240909225952.30324-1-yunwei356@gmail.com

libbpf: fix some typos in libbpf

2024-09-05T20:07:47+00:00

Hi, fix some spelling errors in libbpf, the details are as follows: -in the code comments: termintaing->terminating architecutre->architecture requring->requiring recored->recoded sanitise->sanities allowd->allowed abover->above see bpf_udst_arg()->see bpf_usdt_arg() Signed-off-by: Lin Yikai Link: https://lore.kernel.org/r/20240905110354.3274546-3-yikai.lin@vivo.com Signed-off-by: Alexei Starovoitov

libbpf: Ensure new BTF objects inherit input endianness

2024-08-30T17:41:01+00:00

New split BTF needs to preserve base's endianness. Similarly, when creating a distilled BTF, we need to preserve original endianness. Fix by updating libbpf's btf__distill_base() and btf_new_empty() to retain the byte order of any source BTF objects when creating new ones. Fixes: ba451366bf44 ("libbpf: Implement basic split BTF support") Fixes: 58e185a0dc35 ("libbpf: Add btf__distill_base() creating split BTF with distilled base BTF") Reported-by: Song Liu Reported-by: Eduard Zingerman Suggested-by: Eduard Zingerman Signed-off-by: Tony Ambardar Signed-off-by: Andrii Nakryiko Tested-by: Alan Maguire Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/6358db36c5f68b07873a0a5be2d062b1af5ea5f8.camel@gmail.com/ Link: https://lore.kernel.org/bpf/20240830095150.278881-1-tony.ambardar@gmail.com

libbpf: Fix error handling in btf__distill_base()

2024-07-01T15:05:08+00:00

Coverity points out that after calling btf__new_empty_split() the wrong value is checked for error. Fixes: 58e185a0dc35 ("libbpf: Add btf__distill_base() creating split BTF with distilled base BTF") Reported-by: Andrii Nakryiko Signed-off-by: Alan Maguire Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20240629100058.2866763-1-alan.maguire@oracle.com

libbpf: Skip base btf sanity checks

2024-06-24T16:19:42+00:00

When upgrading to libbpf 1.3 we noticed a big performance hit while loading programs using CORE on non base-BTF symbols. This was tracked down to the new BTF sanity check logic. The issue is the base BTF definitions are checked first for the base BTF and then again for every module BTF. Loading 5 dummy programs (using libbpf-rs) that are using CORE on a non-base BTF symbol on my system: - Before this fix: 3s. - With this fix: 0.1s. Fix this by only checking the types starting at the BTF start id. This should ensure the base BTF is still checked as expected but only once (btf->start_id == 1 when creating the base BTF), and then only additional types are checked for each module BTF. Fixes: 3903802bb99a ("libbpf: Add basic BTF sanity validation") Signed-off-by: Antoine Tenart Signed-off-by: Andrii Nakryiko Reviewed-by: Alan Maguire Link: https://lore.kernel.org/bpf/20240624090908.171231-1-atenart@kernel.org

libbpf: Split field iter code into its own file kernel

2024-06-21T21:45:07+00:00

This will allow it to be shared with the kernel. No functional change. Suggested-by: Andrii Nakryiko Signed-off-by: Alan Maguire Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240620091733.1967885-4-alan.maguire@oracle.com