From: Song Liu <song@kernel.org>
To: <live-patching@vger.kernel.org>
Cc: <jpoimboe@kernel.org>, <jikos@kernel.org>, <mbenes@suse.cz>,
<pmladek@suse.com>, <joe.lawrence@redhat.com>,
<kernel-team@meta.com>, <thunder.leizhen@huawei.com>,
<mcgrof@kernel.org>, Song Liu <song@kernel.org>
Subject: [PATCH] kallsyms: let kallsyms_on_each_match_symbol match symbols exactly
Date: Thu, 15 Jun 2023 10:00:48 -0700 [thread overview]
Message-ID: <20230615170048.2382735-1-song@kernel.org> (raw)
With CONFIG_LTO_CLANG, kallsyms.c:cleanup_symbol_name() removes symbols
suffixes during comparison. This is problematic for livepatch, as
kallsyms_on_each_match_symbol may find multiple matches for the same
symbol, and fail with:
livepatch: unresolvable ambiguity for symbol 'xxx' in object 'yyy'
Make kallsyms_on_each_match_symbol() to match symbols exactly. Since
livepatch is the only user of kallsyms_on_each_match_symbol(), this
change is safe.
Signed-off-by: Song Liu <song@kernel.org>
---
kernel/kallsyms.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 77747391f49b..2ab459b43084 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -187,7 +187,7 @@ static bool cleanup_symbol_name(char *s)
return false;
}
-static int compare_symbol_name(const char *name, char *namebuf)
+static int compare_symbol_name(const char *name, char *namebuf, bool match_exactly)
{
int ret;
@@ -195,7 +195,7 @@ static int compare_symbol_name(const char *name, char *namebuf)
if (!ret)
return ret;
- if (cleanup_symbol_name(namebuf) && !strcmp(name, namebuf))
+ if (!match_exactly && cleanup_symbol_name(namebuf) && !strcmp(name, namebuf))
return 0;
return ret;
@@ -213,7 +213,8 @@ static unsigned int get_symbol_seq(int index)
static int kallsyms_lookup_names(const char *name,
unsigned int *start,
- unsigned int *end)
+ unsigned int *end,
+ bool match_exactly)
{
int ret;
int low, mid, high;
@@ -228,7 +229,7 @@ static int kallsyms_lookup_names(const char *name,
seq = get_symbol_seq(mid);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
- ret = compare_symbol_name(name, namebuf);
+ ret = compare_symbol_name(name, namebuf, match_exactly);
if (ret > 0)
low = mid + 1;
else if (ret < 0)
@@ -245,7 +246,7 @@ static int kallsyms_lookup_names(const char *name,
seq = get_symbol_seq(low - 1);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
- if (compare_symbol_name(name, namebuf))
+ if (compare_symbol_name(name, namebuf, match_exactly))
break;
low--;
}
@@ -257,7 +258,7 @@ static int kallsyms_lookup_names(const char *name,
seq = get_symbol_seq(high + 1);
off = get_symbol_offset(seq);
kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
- if (compare_symbol_name(name, namebuf))
+ if (compare_symbol_name(name, namebuf, match_exactly))
break;
high++;
}
@@ -277,7 +278,7 @@ unsigned long kallsyms_lookup_name(const char *name)
if (!*name)
return 0;
- ret = kallsyms_lookup_names(name, &i, NULL);
+ ret = kallsyms_lookup_names(name, &i, NULL, false);
if (!ret)
return kallsyms_sym_address(get_symbol_seq(i));
@@ -312,7 +313,7 @@ int kallsyms_on_each_match_symbol(int (*fn)(void *, unsigned long),
int ret;
unsigned int i, start, end;
- ret = kallsyms_lookup_names(name, &start, &end);
+ ret = kallsyms_lookup_names(name, &start, &end, true);
if (ret)
return 0;
--
2.34.1
next reply other threads:[~2023-06-15 17:01 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-15 17:00 Song Liu [this message]
2023-06-16 2:19 ` [PATCH] kallsyms: let kallsyms_on_each_match_symbol match symbols exactly Leizhen (ThunderTown)
2023-06-16 5:01 ` Song Liu
2023-06-16 8:11 ` Leizhen (ThunderTown)
2023-06-16 8:43 ` Leizhen (ThunderTown)
2023-06-16 8:52 ` Leizhen (ThunderTown)
2023-06-16 17:40 ` Song Liu
2023-06-16 9:31 ` Leizhen (ThunderTown)
2023-06-16 17:37 ` Song Liu
2023-06-19 3:32 ` Leizhen (ThunderTown)
2023-06-19 5:05 ` Song Liu
2023-06-19 11:32 ` Petr Mladek
2023-06-20 22:36 ` Song Liu
2023-06-21 8:52 ` Petr Mladek
2023-06-21 19:18 ` Song Liu
2023-06-21 22:34 ` Yonghong Song
2023-06-22 13:35 ` Petr Mladek
2023-06-22 16:10 ` Yonghong Song
[not found] ` <4616610E-180A-4417-8592-B864F6298C7F@fb.com>
2023-06-22 20:45 ` Yonghong Song
2023-06-23 17:43 ` Nick Desaulniers
2023-06-25 19:06 ` Yonghong Song
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