Our formatted output helpers are currently implemented with snprintf-like functions which take arguments as va_list but the types stored in a va_list need to be known at compilation time which causes problems when dealing with arguments from the BPF world that are always u64 but considered differently depending on the format specifiers they are associated with at runtime. This series replaces snprintf usages with bstr_printf calls. This lets us construct a binary representation of arguments in bpf_printf_prepare at runtime that matches an ABI that is neither arch nor compiler specific. This solves a bug reported by Rasmus Villemoes that would mangle arguments on 32 bit machines. Florent Revest (2): seq_file: Add a seq_bprintf function bpf: Implement formatted output helpers with bstr_printf fs/seq_file.c | 18 ++++ include/linux/bpf.h | 22 +---- include/linux/seq_file.h | 4 + init/Kconfig | 1 + kernel/bpf/helpers.c | 188 +++++++++++++++++++++------------------ kernel/bpf/verifier.c | 2 +- kernel/trace/bpf_trace.c | 34 +++---- 7 files changed, 137 insertions(+), 132 deletions(-) -- 2.31.1.498.g6c1eba8ee3d-goog
