vsprintf: fix %ps on non symbols when using kallsyms
Using %ps in a printk format will sometimes fail silently and print the
empty string if the address passed in does not match a symbol that
kallsyms knows about. But using %pS will fall back to printing the full
address if kallsyms can't find the symbol. Make %ps act the same as %pS
by falling back to printing the address.
While we're here also make %ps print the module that a symbol comes from
so that it matches what %pS already does. Take this simple function for
example (in a module):
static void test_printk(void)
{
int test;
pr_info("with pS: %pS\n", &test);
pr_info("with ps: %ps\n", &test);
}
Before this patch:
with pS: 0xdff7df44
with ps:
After this patch:
with pS: 0xdff7df44
with ps: 0xdff7df44
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 079f1d3..2169fee 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -343,7 +343,7 @@
/* Look up a kernel symbol and return it in a text buffer. */
static int __sprint_symbol(char *buffer, unsigned long address,
- int symbol_offset)
+ int symbol_offset, int add_offset)
{
char *modname;
const char *name;
@@ -358,13 +358,13 @@
if (name != buffer)
strcpy(buffer, name);
len = strlen(buffer);
- buffer += len;
offset -= symbol_offset;
+ if (add_offset)
+ len += sprintf(buffer + len, "+%#lx/%#lx", offset, size);
+
if (modname)
- len += sprintf(buffer, "+%#lx/%#lx [%s]", offset, size, modname);
- else
- len += sprintf(buffer, "+%#lx/%#lx", offset, size);
+ len += sprintf(buffer + len, " [%s]", modname);
return len;
}
@@ -382,12 +382,28 @@
*/
int sprint_symbol(char *buffer, unsigned long address)
{
- return __sprint_symbol(buffer, address, 0);
+ return __sprint_symbol(buffer, address, 0, 1);
}
-
EXPORT_SYMBOL_GPL(sprint_symbol);
/**
+ * sprint_symbol_no_offset - Look up a kernel symbol and return it in a text buffer
+ * @buffer: buffer to be stored
+ * @address: address to lookup
+ *
+ * This function looks up a kernel symbol with @address and stores its name
+ * and module name to @buffer if possible. If no symbol was found, just saves
+ * its @address as is.
+ *
+ * This function returns the number of bytes stored in @buffer.
+ */
+int sprint_symbol_no_offset(char *buffer, unsigned long address)
+{
+ return __sprint_symbol(buffer, address, 0, 0);
+}
+EXPORT_SYMBOL_GPL(sprint_symbol_no_offset);
+
+/**
* sprint_backtrace - Look up a backtrace symbol and return it in a text buffer
* @buffer: buffer to be stored
* @address: address to lookup
@@ -403,7 +419,7 @@
*/
int sprint_backtrace(char *buffer, unsigned long address)
{
- return __sprint_symbol(buffer, address, -1);
+ return __sprint_symbol(buffer, address, -1, 1);
}
/* Look up a kernel symbol and print it to the kernel messages. */