6.6-stable review patch. If anyone has any objections, please let me know.
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From: Andrii Nakryiko andrii@kernel.org
[ Upstream commit 98ebe5ef6f5c4517ba92fb3e56f95827ebea83fd ]
USDT ELF note optionally can record an offset of .stapsdt.base, which is used to make adjustments to USDT target attach address. Currently, libbpf will do this address adjustment unconditionally if it finds .stapsdt.base ELF section in target binary. But there is a corner case where .stapsdt.base ELF section is present, but specific USDT note doesn't reference it. In such case, libbpf will basically just add base address and end up with absolutely incorrect USDT target address.
This adjustment has to be done only if both .stapsdt.sema section is present and USDT note is recording a reference to it.
Fixes: 74cc6311cec9 ("libbpf: Add USDT notes parsing and resolution logic") Signed-off-by: Andrii Nakryiko andrii@kernel.org Acked-by: Jiri Olsa jolsa@kernel.org Link: https://lore.kernel.org/r/20241121224558.796110-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/usdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c index 93794f01bb67c..6ff28e7bf5e3d 100644 --- a/tools/lib/bpf/usdt.c +++ b/tools/lib/bpf/usdt.c @@ -659,7 +659,7 @@ static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char * * [0] https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation */ usdt_abs_ip = note.loc_addr; - if (base_addr) + if (base_addr && note.base_addr) usdt_abs_ip += base_addr - note.base_addr;
/* When attaching uprobes (which is what USDTs basically are)