getline() returns -1 at EOF as well as on error. It also doesn't set errno to 0 on success, so initialize it to 0 before using errno to check for an error condition. See the paragraph here [1]: For some system calls and library functions (e.g., getpriority(2)), -1 is a valid return on success. In such cases, a successful return can be distinguished from an error return by setting errno to zero before the call, and then, if the call returns a status that indicates that an error may have occurred, checking to see if errno has a nonzero value. This fixes the following build failure if scripts/kallsyms launches with a non-zero errno value: $ make ... LD .tmp_vmlinux.kallsyms1 NM .tmp_vmlinux.kallsyms1.syms KSYMS .tmp_vmlinux.kallsyms1.S read_symbol: Invalid argument [1]: https://linux.die.net/man/3/errno Fixes: 1c975da56a6f ("scripts/kallsyms: remove KSYM_NAME_LEN_BUFFER") Signed-off-by: James Clark <james.clark@xxxxxxx> --- scripts/kallsyms.c | 1 + 1 file changed, 1 insertion(+) diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 16c87938b316..653b92f6d4c8 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -129,6 +129,7 @@ static struct sym_entry *read_symbol(FILE *in, char **buf, size_t *buf_len) ssize_t readlen; struct sym_entry *sym; + errno = 0; readlen = getline(buf, buf_len, in); if (readlen < 0) { if (errno) { -- 2.34.1
