This is a note to let you know that I've just added the patch titled
libbpf: fix sym_is_subprog() logic for weak global subprogs
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
libbpf-fix-sym_is_subprog-logic-for-weak-global-subp.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 021b53d7eeaa1d66d9f270b15a6a56ea54d70a6a
Author: Andrii Nakryiko <andrii@xxxxxxxxxx>
Date: Tue Oct 8 18:15:54 2024 -0700
libbpf: fix sym_is_subprog() logic for weak global subprogs
[ Upstream commit 4073213488be542f563eb4b2457ab4cbcfc2b738 ]
sym_is_subprog() is incorrectly rejecting relocations against *weak*
global subprogs. Fix that by realizing that STB_WEAK is also a global
function.
While it seems like verifier doesn't support taking an address of
non-static subprog right now, it's still best to fix support for it on
libbpf side, otherwise users will get a very confusing error during BPF
skeleton generation or static linking due to misinterpreted relocation:
libbpf: prog 'handle_tp': bad map relo against 'foo' in section '.text'
Error: failed to open BPF object file: Relocation failed
It's clearly not a map relocation, but is treated and reported as such
without this fix.
Fixes: 53eddb5e04ac ("libbpf: Support subprog address relocation")
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20241009011554.880168-1-andrii@xxxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 878f05a424218..d8b5304eac8cd 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3501,7 +3501,7 @@ static bool sym_is_subprog(const Elf64_Sym *sym, int text_shndx)
return true;
/* global function */
- return bind == STB_GLOBAL && type == STT_FUNC;
+ return (bind == STB_GLOBAL || bind == STB_WEAK) && type == STT_FUNC;
}
static int find_extern_btf_id(const struct btf *btf, const char *ext_name)
