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Message-Id: <20230724131741.954624-1-james.clark@arm.com>
Date: Mon, 24 Jul 2023 14:17:40 +0100
From: James Clark <james.clark@....com>
To: linux-kbuild@...r.kernel.org, masahiroy@...nel.org
Cc: linux-kernel@...r.kernel.org, James Clark <james.clark@....com>,
Kees Cook <keescook@...omium.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Zhen Lei <thunder.leizhen@...wei.com>,
Miguel Ojeda <ojeda@...nel.org>,
Boqun Feng <boqun.feng@...il.com>,
Arnd Bergmann <arnd@...db.de>, Nicolas Schier <n.schier@....de>
Subject: [PATCH] scripts/kallsyms: Fix build failure by setting errno before calling getline()
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@....com>
---
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
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