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Author	SHA1	Message	Date
Emil Tsalapatis	9dd6fda504	libbpf: Move arena globals to the end of the arena ... Arena globals are currently placed at the beginning of the arena by libbpf. This is convenient, but prevents users from reserving guard pages in the beginning of the arena to identify NULL pointer dereferences. Adjust the load logic to place the globals at the end of the arena instead. Also modify bpftool to set the arena pointer in the program's BPF skeleton to point to the globals. Users now call bpf_map__initial_value() to find the beginning of the arena mapping and use the arena pointer in the skeleton to determine which part of the mapping holds the arena globals and which part is free. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20251216173325.98465-5-emil@etsalapatis.com	2026-01-29 14:10:19 -08:00
Emil Tsalapatis	2c7fe6ec5d	libbpf: Turn relo_core->sym_off unsigned ... The symbols' relocation offsets in BPF are stored in an int field, but cannot actually be negative. When in the next patch libbpf relocates globals to the end of the arena, it is also possible to have valid offsets > 2GiB that are used to calculate the final relo offsets. Avoid accidentally interpreting large offsets as negative by turning the sym_off field unsigned. Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20251216173325.98465-4-emil@etsalapatis.com	2026-01-29 14:10:19 -08:00