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authorStephen Boyd <sboyd@codeaurora.org>2012-05-29 15:07:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-29 16:22:32 -0700
commit4796dd200db943e36f876e7029552212e5bbdf33 (patch)
treea594c2b1ce1f4dbc96b25a516e49655917a9fa30
parent05a6c8a9226599f921bd0b6e439dbc04df96a6fc (diff)
downloadop-kernel-dev-4796dd200db943e36f876e7029552212e5bbdf33.zip
op-kernel-dev-4796dd200db943e36f876e7029552212e5bbdf33.tar.gz
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>
-rw-r--r--include/linux/kallsyms.h7
-rw-r--r--kernel/kallsyms.c32
-rw-r--r--lib/vsprintf.c2
3 files changed, 32 insertions, 9 deletions
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 3875719..6883e19 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -36,6 +36,7 @@ const char *kallsyms_lookup(unsigned long addr,
/* Look up a kernel symbol and return it in a text buffer. */
extern int sprint_symbol(char *buffer, unsigned long address);
+extern int sprint_symbol_no_offset(char *buffer, unsigned long address);
extern int sprint_backtrace(char *buffer, unsigned long address);
/* Look up a kernel symbol and print it to the kernel messages. */
@@ -80,6 +81,12 @@ static inline int sprint_symbol(char *buffer, unsigned long addr)
return 0;
}
+static inline int sprint_symbol_no_offset(char *buffer, unsigned long addr)
+{
+ *buffer = '\0';
+ return 0;
+}
+
static inline int sprint_backtrace(char *buffer, unsigned long addr)
{
*buffer = '\0';
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 @@ int lookup_symbol_attrs(unsigned long addr, unsigned long *size,
/* 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 @@ static int __sprint_symbol(char *buffer, unsigned long address,
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 @@ static int __sprint_symbol(char *buffer, unsigned long address,
*/
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 @@ EXPORT_SYMBOL_GPL(sprint_symbol);
*/
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. */
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index abbabec..f5dfe0c 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -436,7 +436,7 @@ char *symbol_string(char *buf, char *end, void *ptr,
else if (ext != 'f' && ext != 's')
sprint_symbol(sym, value);
else
- kallsyms_lookup(value, NULL, NULL, NULL, sym);
+ sprint_symbol_no_offset(sym, value);
return string(buf, end, sym, spec);
#else
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