[PATCH 1/3] kbuild: Increase kallsyms max symbol length

[PATCH 1/3] kbuild: Increase kallsyms max symbol length

[Andi Kleen]

From: Joe Mario <jmario@redhat.com>

[AK: This seems like a ticking time bomb even without LTO,
so should be merged now. It causes very weird problems.
Thanks to Joe for tracking them down.]

With the added postfixes that LTO adds for local
symbols, the longest name in the kernel overflows
the namebuf[KSYM_NAME_LEN] array by two bytes.  That name is:
__pci_fixup_resumePCI_VENDOR_ID_SERVERWORKSPCI_DEVICE_ID_SERVERWORKS_HT1000SBquirk_disable_broadcom_boot_interrupt.1488004.672802

Double the max symbol name length.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 include/linux/kallsyms.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 6883e19..711a50f 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -9,7 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/stddef.h>
 
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 256
 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
 			 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
 
-- 
1.8.3.1

[PATCH 2/3] Kbuild: Handle longer symbols in kallsyms.c

[Andi Kleen]

From: Andi Kleen <ak@linux.intel.com>

Also warn for too long symbols

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 scripts/kallsyms.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 6940f00..e5af4c5 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -27,7 +27,7 @@
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
 #endif
 
-#define KSYM_NAME_LEN		128
+#define KSYM_NAME_LEN		256
 
 struct sym_entry {
 	unsigned long long addr;
@@ -118,6 +118,12 @@ static int read_symbol(FILE *in, struct sym_entry *s)
 			fprintf(stderr, "Read error or end of file.\n");
 		return -1;
 	}
+	if (strlen(str) > KSYM_NAME_LEN) {
+		fprintf(stderr, "Symbol %s too long for kallsyms.\n"
+                                "Please increae KSYM_NAME_LEN both in kernel and kallsyms.c",
+			str);
+		return -1;
+	}
 
 	sym = str;
 	/* skip prefix char */
-- 
1.8.3.1

[PATCH 3/3] kprobes: Use KSYM_NAME_LEN to size identifier buffers

[Andi Kleen]

From: Joe Mario <jmario@redhat.com>

Use KSYM_NAME_LEN to size identifier buffers, so that it can
be easier increased.

Cc: ananth@in.ibm.com
Signed-off-by: Joe Mario <jmario@redhat.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 kernel/kprobes.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 6e33498..e174daf 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2083,7 +2083,7 @@ static int __init init_kprobes(void)
 {
 	int i, err = 0;
 	unsigned long offset = 0, size = 0;
-	char *modname, namebuf[128];
+	char *modname, namebuf[KSYM_NAME_LEN];
 	const char *symbol_name;
 	void *addr;
 	struct kprobe_blackpoint *kb;
@@ -2209,7 +2209,7 @@ static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
 	const char *sym = NULL;
 	unsigned int i = *(loff_t *) v;
 	unsigned long offset = 0;
-	char *modname, namebuf[128];
+	char *modname, namebuf[KSYM_NAME_LEN];
 
 	head = &kprobe_table[i];
 	preempt_disable();
-- 
1.8.3.1

Re: [PATCH 3/3] kprobes: Use KSYM_NAME_LEN to size identifier buffers

[Ananth N Mavinakayanahalli]

On Sat, Aug 10, 2013 at 05:55:33PM -0700, Andi Kleen wrote:
> From: Joe Mario <jmario@redhat.com>
> 
> Use KSYM_NAME_LEN to size identifier buffers, so that it can
> be easier increased.
> 
> Cc: ananth@in.ibm.com
> Signed-off-by: Joe Mario <jmario@redhat.com>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>

Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>

> ---
>  kernel/kprobes.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 6e33498..e174daf 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -2083,7 +2083,7 @@ static int __init init_kprobes(void)
>  {
>  	int i, err = 0;
>  	unsigned long offset = 0, size = 0;
> -	char *modname, namebuf[128];
> +	char *modname, namebuf[KSYM_NAME_LEN];
>  	const char *symbol_name;
>  	void *addr;
>  	struct kprobe_blackpoint *kb;
> @@ -2209,7 +2209,7 @@ static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
>  	const char *sym = NULL;
>  	unsigned int i = *(loff_t *) v;
>  	unsigned long offset = 0;
> -	char *modname, namebuf[128];
> +	char *modname, namebuf[KSYM_NAME_LEN];
> 
>  	head = &kprobe_table[i];
>  	preempt_disable();
> -- 
> 1.8.3.1

[PATCH 1/3] kbuild: Increase kallsyms max symbol length

[Andi Kleen]

From: Joe Mario <jmario@redhat.com>

[AK: This seems like a ticking time bomb even without LTO,
so should be merged now. It causes very weird problems.
Thanks to Joe for tracking them down.]

With the added postfixes that LTO adds for local
symbols, the longest name in the kernel overflows
the namebuf[KSYM_NAME_LEN] array by two bytes.  That name is:
__pci_fixup_resumePCI_VENDOR_ID_SERVERWORKSPCI_DEVICE_ID_SERVERWORKS_HT1000SBquirk_disable_broadcom_boot_interrupt.1488004.672802

Double the max symbol name length.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 include/linux/kallsyms.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 6883e19..711a50f 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -9,7 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/stddef.h>
 
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 256
 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
 			 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
 
-- 
1.8.3.1

Re: [PATCH 1/3] kbuild: Increase kallsyms max symbol length

[Joe Perches]

On Tue, 2013-10-22 at 08:46 -0700, Andi Kleen wrote:
> From: Joe Mario <jmario@redhat.com>
> 
> [AK: This seems like a ticking time bomb even without LTO,
> so should be merged now. It causes very weird problems.
> Thanks to Joe for tracking them down.]
> 
> With the added postfixes that LTO adds for local
> symbols, the longest name in the kernel overflows
> the namebuf[KSYM_NAME_LEN] array by two bytes.  That name is:
> __pci_fixup_resumePCI_VENDOR_ID_SERVERWORKSPCI_DEVICE_ID_SERVERWORKS_HT1000SBquirk_disable_broadcom_boot_interrupt.1488004.672802
> 
> Double the max symbol name length.
[]
> diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
> index 6883e19..711a50f 100644
> --- a/include/linux/kallsyms.h
> +++ b/include/linux/kallsyms.h
> @@ -9,7 +9,7 @@
>  #include <linux/kernel.h>
>  #include <linux/stddef.h>
>  
> -#define KSYM_NAME_LEN 128
> +#define KSYM_NAME_LEN 256

Doesn't doubling seems a tad excessive given the
silly length of that symbol above?

Re: [PATCH 1/3] kbuild: Increase kallsyms max symbol length

[Andi Kleen]

> Doesn't doubling seems a tad excessive given the
> silly length of that symbol above?

No, it doesn't.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

Re: [PATCH 1/3] kbuild: Increase kallsyms max symbol length

[Joe Perches]

On Tue, 2013-10-22 at 18:40 +0200, Andi Kleen wrote:
> > Doesn't doubling seems a tad excessive given the
> > silly length of that symbol above?
> 
> No, it doesn't.

Does it work?

Doesn't kallsyms:get_symbol_offset restrict the maximum
possible length to 255?