Hi,
Here is code to scan modules in kgdb for 2.6 kernels. It's been contributed by
TimeSys Corporation.
It does following things:
1. Adds MODULE_STATE_GONE to indicate that a module was removed. This is
differnent from MODULE_STATE_GOING. gdb needs to be notified of a module
event _after_ a module has been removed. Or else it'll still find the module
during a module list scan and will not remove it from its core.
2. Defines a structure mod_section which stores module section names and
offsets preserved during loading of a module.
3. Adds a couple of fields to struct module to keep module section
information.
4. Adds a few notifications for gdb to know module related events.
5. Saves module section names and offsets in load_module.
-Amit
Index: linux-2.6.3-kgdb/include/linux/module.h
===================================================================
--- linux-2.6.3-kgdb.orig/include/linux/module.h 2004-02-24 10:44:47.000000000
+0530
+++ linux-2.6.3-kgdb/include/linux/module.h 2004-03-04 18:58:47.116645760
+0530
@@ -186,8 +186,17 @@
MODULE_STATE_LIVE,
MODULE_STATE_COMING,
MODULE_STATE_GOING,
+ MODULE_STATE_GONE,
};
+#ifdef CONFIG_KGDB
+#define MAX_SECTNAME 31
+struct mod_section {
+ void *address;
+ char name[MAX_SECTNAME + 1];
+};
+#endif
+
struct module
{
enum module_state state;
@@ -198,6 +207,13 @@
/* Unique handle for this module */
char name[MODULE_NAME_LEN];
+#ifdef CONFIG_KGDB
+ /* keep kgdb info at the begining so that gdb doesn't have a chance to
+ * miss out any fields */
+ unsigned long num_sections;
+ struct mod_section *mod_sections;
+#endif
+
/* Exported symbols */
const struct kernel_symbol *syms;
unsigned int num_syms;
Index: linux-2.6.3-kgdb/kernel/module.c
===================================================================
--- linux-2.6.3-kgdb.orig/kernel/module.c 2004-02-24 10:44:56.000000000 +0530
+++ linux-2.6.3-kgdb/kernel/module.c 2004-03-04 18:55:59.136182672 +0530
@@ -727,6 +727,11 @@
mod->state = MODULE_STATE_GOING;
restart_refcounts();
+ down(¬ify_mutex);
+ notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
+ mod);
+ up(¬ify_mutex);
+
/* Never wait if forced. */
if (!forced && module_refcount(mod) != 0)
wait_for_zero_refcount(mod);
@@ -734,6 +739,10 @@
/* Final destruction now noone is using it. */
mod->exit();
free_module(mod);
+ down(¬ify_mutex);
+ notifier_call_chain(&module_notify_list, MODULE_STATE_GONE,
+ NULL);
+ up(¬ify_mutex);
out:
up(&module_mutex);
@@ -1087,6 +1096,11 @@
/* Arch-specific cleanup. */
module_arch_cleanup(mod);
+#ifdef CONFIG_KGDB
+ /* kgdb info */
+ vfree(mod->mod_sections);
+#endif
+
/* Module unload stuff */
module_unload_free(mod);
@@ -1302,6 +1316,30 @@
return NULL;
}
+#ifdef CONFIG_KGDB
+int add_modsects (struct module *mod, Elf_Ehdr *hdr, Elf_Shdr *sechdrs, const
+ char *secstrings)
+{
+ int i;
+
+ mod->num_sections = hdr->e_shnum - 1;
+ mod->mod_sections = vmalloc((hdr->e_shnum - 1)* sizeof (struct
mod_section));
+
+ if (mod->mod_sections == NULL) {
+ return -ENOMEM;
+ }
+
+ for (i = 1; i < hdr->e_shnum; i++) {
+ mod->mod_sections[i - 1].address = (void *)sechdrs[i].sh_addr;
+ strncpy(mod->mod_sections[i - 1].name, secstrings +
+ sechdrs[i].sh_name, MAX_SECTNAME);
+ mod->mod_sections[i - 1].name[MAX_SECTNAME] = '\0';
+ }
+
+ return 0;
+}
+#endif
+
#ifdef CONFIG_KALLSYMS
int is_exported(const char *name, const struct module *mod)
{
@@ -1650,6 +1688,12 @@
percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr,
sechdrs[pcpuindex].sh_size);
+#ifdef CONFIG_KGDB
+ if ((err = add_modsects(mod, hdr, sechdrs, secstrings)) < 0) {
+ goto nomodsectinfo;
+ }
+#endif
+
err = module_finalize(hdr, sechdrs, mod);
if (err < 0)
goto cleanup;
@@ -1688,6 +1732,11 @@
arch_cleanup:
module_arch_cleanup(mod);
cleanup:
+
+#ifdef CONFIG_KGDB
+nomodsectinfo:
+ vfree(mod->mod_sections);
+#endif
module_unload_free(mod);
module_free(mod, mod->module_init);
free_core:
@@ -1758,7 +1807,12 @@
if (ret < 0) {
/* Init routine failed: abort. Try to protect us from
buggy refcounters. */
+
mod->state = MODULE_STATE_GOING;
+ down(¬ify_mutex);
+ notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
+ mod);
+ up(¬ify_mutex);
synchronize_kernel();
if (mod->unsafe)
printk(KERN_ERR "%s: module is now stuck!\n",
The gdb code for this is completely different from the one that works with 2.4
kernels. I'll post it at kgdb.sourceforge.net when I checkin this change.
-Amit
On Friday 12 Mar 2004 12:06 pm, Amit S. Kale wrote:
> Hi,
>
> Here is code to scan modules in kgdb for 2.6 kernels. It's been contributed
> by TimeSys Corporation.
>
> It does following things:
> 1. Adds MODULE_STATE_GONE to indicate that a module was removed. This is
> differnent from MODULE_STATE_GOING. gdb needs to be notified of a module
> event _after_ a module has been removed. Or else it'll still find the
> module during a module list scan and will not remove it from its core.
>
> 2. Defines a structure mod_section which stores module section names and
> offsets preserved during loading of a module.
>
> 3. Adds a couple of fields to struct module to keep module section
> information.
>
> 4. Adds a few notifications for gdb to know module related events.
>
> 5. Saves module section names and offsets in load_module.
>
> -Amit
>
> Index: linux-2.6.3-kgdb/include/linux/module.h
> ===================================================================
> --- linux-2.6.3-kgdb.orig/include/linux/module.h 2004-02-24
> 10:44:47.000000000 +0530
> +++ linux-2.6.3-kgdb/include/linux/module.h 2004-03-04 18:58:47.116645760
> +0530
> @@ -186,8 +186,17 @@
> MODULE_STATE_LIVE,
> MODULE_STATE_COMING,
> MODULE_STATE_GOING,
> + MODULE_STATE_GONE,
> };
>
> +#ifdef CONFIG_KGDB
> +#define MAX_SECTNAME 31
> +struct mod_section {
> + void *address;
> + char name[MAX_SECTNAME + 1];
> +};
> +#endif
> +
> struct module
> {
> enum module_state state;
> @@ -198,6 +207,13 @@
> /* Unique handle for this module */
> char name[MODULE_NAME_LEN];
>
> +#ifdef CONFIG_KGDB
> + /* keep kgdb info at the begining so that gdb doesn't have a chance to
> + * miss out any fields */
> + unsigned long num_sections;
> + struct mod_section *mod_sections;
> +#endif
> +
> /* Exported symbols */
> const struct kernel_symbol *syms;
> unsigned int num_syms;
> Index: linux-2.6.3-kgdb/kernel/module.c
> ===================================================================
> --- linux-2.6.3-kgdb.orig/kernel/module.c 2004-02-24 10:44:56.000000000
> +0530 +++ linux-2.6.3-kgdb/kernel/module.c 2004-03-04 18:55:59.136182672
> +0530 @@ -727,6 +727,11 @@
> mod->state = MODULE_STATE_GOING;
> restart_refcounts();
>
> + down(¬ify_mutex);
> + notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
> + mod);
> + up(¬ify_mutex);
> +
> /* Never wait if forced. */
> if (!forced && module_refcount(mod) != 0)
> wait_for_zero_refcount(mod);
> @@ -734,6 +739,10 @@
> /* Final destruction now noone is using it. */
> mod->exit();
> free_module(mod);
> + down(¬ify_mutex);
> + notifier_call_chain(&module_notify_list, MODULE_STATE_GONE,
> + NULL);
> + up(¬ify_mutex);
>
> out:
> up(&module_mutex);
> @@ -1087,6 +1096,11 @@
> /* Arch-specific cleanup. */
> module_arch_cleanup(mod);
>
> +#ifdef CONFIG_KGDB
> + /* kgdb info */
> + vfree(mod->mod_sections);
> +#endif
> +
> /* Module unload stuff */
> module_unload_free(mod);
>
> @@ -1302,6 +1316,30 @@
> return NULL;
> }
>
> +#ifdef CONFIG_KGDB
> +int add_modsects (struct module *mod, Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
> const + char *secstrings)
> +{
> + int i;
> +
> + mod->num_sections = hdr->e_shnum - 1;
> + mod->mod_sections = vmalloc((hdr->e_shnum - 1)* sizeof (struct
> mod_section));
> +
> + if (mod->mod_sections == NULL) {
> + return -ENOMEM;
> + }
> +
> + for (i = 1; i < hdr->e_shnum; i++) {
> + mod->mod_sections[i - 1].address = (void *)sechdrs[i].sh_addr;
> + strncpy(mod->mod_sections[i - 1].name, secstrings +
> + sechdrs[i].sh_name, MAX_SECTNAME);
> + mod->mod_sections[i - 1].name[MAX_SECTNAME] = '\0';
> + }
> +
> + return 0;
> +}
> +#endif
> +
> #ifdef CONFIG_KALLSYMS
> int is_exported(const char *name, const struct module *mod)
> {
> @@ -1650,6 +1688,12 @@
> percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr,
> sechdrs[pcpuindex].sh_size);
>
> +#ifdef CONFIG_KGDB
> + if ((err = add_modsects(mod, hdr, sechdrs, secstrings)) < 0) {
> + goto nomodsectinfo;
> + }
> +#endif
> +
> err = module_finalize(hdr, sechdrs, mod);
> if (err < 0)
> goto cleanup;
> @@ -1688,6 +1732,11 @@
> arch_cleanup:
> module_arch_cleanup(mod);
> cleanup:
> +
> +#ifdef CONFIG_KGDB
> +nomodsectinfo:
> + vfree(mod->mod_sections);
> +#endif
> module_unload_free(mod);
> module_free(mod, mod->module_init);
> free_core:
> @@ -1758,7 +1807,12 @@
> if (ret < 0) {
> /* Init routine failed: abort. Try to protect us from
> buggy refcounters. */
> +
> mod->state = MODULE_STATE_GOING;
> + down(¬ify_mutex);
> + notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
> + mod);
> + up(¬ify_mutex);
> synchronize_kernel();
> if (mod->unsafe)
> printk(KERN_ERR "%s: module is now stuck!\n",
>
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by: IBM Linux Tutorials
> Free Linux tutorial presented by Daniel Robbins, President and CEO of
> GenToo technologies. Learn everything from fundamentals to system
> administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click
> _______________________________________________
> Kgdb-bugreport mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
On Fri, 2004-03-12 at 17:36, Amit S. Kale wrote:
> Hi,
Hi Amit,
FYI: you would have received a quicker response if you'd CC'd me.
> It does following things:
> 1. Adds MODULE_STATE_GONE to indicate that a module was removed. This is
> differnent from MODULE_STATE_GOING. gdb needs to be notified of a module
> event _after_ a module has been removed. Or else it'll still find the module
> during a module list scan and will not remove it from its core.
Makes sense.
> 2. Defines a structure mod_section which stores module section names and
> offsets preserved during loading of a module.
>
> 3. Adds a couple of fields to struct module to keep module section
> information.
Why not just set the section strings to SHF_ALLOC rather than copying
(and possibly truncating) the names into your struct mod_section?
struct mod_section is then simply void *addr; char *name;
Cheers,
Rusty.
--
Anyone who quotes me in their signature is an idiot -- Rusty Russell
Hi,
I have checked in this kgdb change and uploaded the gdb to be used with it.
Both kgdb and gdb code for this feature has been contributed by TimeSys
Corporation.
-Amit
On Friday 12 Mar 2004 12:30 pm, Amit S. Kale wrote:
> The gdb code for this is completely different from the one that works with
> 2.4 kernels. I'll post it at kgdb.sourceforge.net when I checkin this
> change.
>
> -Amit
>
> On Friday 12 Mar 2004 12:06 pm, Amit S. Kale wrote:
> > Hi,
> >
> > Here is code to scan modules in kgdb for 2.6 kernels. It's been
> > contributed by TimeSys Corporation.
> >
> > It does following things:
> > 1. Adds MODULE_STATE_GONE to indicate that a module was removed. This is
> > differnent from MODULE_STATE_GOING. gdb needs to be notified of a module
> > event _after_ a module has been removed. Or else it'll still find the
> > module during a module list scan and will not remove it from its core.
> >
> > 2. Defines a structure mod_section which stores module section names and
> > offsets preserved during loading of a module.
> >
> > 3. Adds a couple of fields to struct module to keep module section
> > information.
> >
> > 4. Adds a few notifications for gdb to know module related events.
> >
> > 5. Saves module section names and offsets in load_module.
> >
> > -Amit
> >
> > Index: linux-2.6.3-kgdb/include/linux/module.h
> > ===================================================================
> > --- linux-2.6.3-kgdb.orig/include/linux/module.h 2004-02-24
> > 10:44:47.000000000 +0530
> > +++ linux-2.6.3-kgdb/include/linux/module.h 2004-03-04 18:58:47.116645760
> > +0530
> > @@ -186,8 +186,17 @@
> > MODULE_STATE_LIVE,
> > MODULE_STATE_COMING,
> > MODULE_STATE_GOING,
> > + MODULE_STATE_GONE,
> > };
> >
> > +#ifdef CONFIG_KGDB
> > +#define MAX_SECTNAME 31
> > +struct mod_section {
> > + void *address;
> > + char name[MAX_SECTNAME + 1];
> > +};
> > +#endif
> > +
> > struct module
> > {
> > enum module_state state;
> > @@ -198,6 +207,13 @@
> > /* Unique handle for this module */
> > char name[MODULE_NAME_LEN];
> >
> > +#ifdef CONFIG_KGDB
> > + /* keep kgdb info at the begining so that gdb doesn't have a chance to
> > + * miss out any fields */
> > + unsigned long num_sections;
> > + struct mod_section *mod_sections;
> > +#endif
> > +
> > /* Exported symbols */
> > const struct kernel_symbol *syms;
> > unsigned int num_syms;
> > Index: linux-2.6.3-kgdb/kernel/module.c
> > ===================================================================
> > --- linux-2.6.3-kgdb.orig/kernel/module.c 2004-02-24 10:44:56.000000000
> > +0530 +++ linux-2.6.3-kgdb/kernel/module.c 2004-03-04 18:55:59.136182672
> > +0530 @@ -727,6 +727,11 @@
> > mod->state = MODULE_STATE_GOING;
> > restart_refcounts();
> >
> > + down(¬ify_mutex);
> > + notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
> > + mod);
> > + up(¬ify_mutex);
> > +
> > /* Never wait if forced. */
> > if (!forced && module_refcount(mod) != 0)
> > wait_for_zero_refcount(mod);
> > @@ -734,6 +739,10 @@
> > /* Final destruction now noone is using it. */
> > mod->exit();
> > free_module(mod);
> > + down(¬ify_mutex);
> > + notifier_call_chain(&module_notify_list, MODULE_STATE_GONE,
> > + NULL);
> > + up(¬ify_mutex);
> >
> > out:
> > up(&module_mutex);
> > @@ -1087,6 +1096,11 @@
> > /* Arch-specific cleanup. */
> > module_arch_cleanup(mod);
> >
> > +#ifdef CONFIG_KGDB
> > + /* kgdb info */
> > + vfree(mod->mod_sections);
> > +#endif
> > +
> > /* Module unload stuff */
> > module_unload_free(mod);
> >
> > @@ -1302,6 +1316,30 @@
> > return NULL;
> > }
> >
> > +#ifdef CONFIG_KGDB
> > +int add_modsects (struct module *mod, Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
> > const + char *secstrings)
> > +{
> > + int i;
> > +
> > + mod->num_sections = hdr->e_shnum - 1;
> > + mod->mod_sections = vmalloc((hdr->e_shnum - 1)* sizeof (struct
> > mod_section));
> > +
> > + if (mod->mod_sections == NULL) {
> > + return -ENOMEM;
> > + }
> > +
> > + for (i = 1; i < hdr->e_shnum; i++) {
> > + mod->mod_sections[i - 1].address = (void *)sechdrs[i].sh_addr;
> > + strncpy(mod->mod_sections[i - 1].name, secstrings +
> > + sechdrs[i].sh_name, MAX_SECTNAME);
> > + mod->mod_sections[i - 1].name[MAX_SECTNAME] = '\0';
> > + }
> > +
> > + return 0;
> > +}
> > +#endif
> > +
> > #ifdef CONFIG_KALLSYMS
> > int is_exported(const char *name, const struct module *mod)
> > {
> > @@ -1650,6 +1688,12 @@
> > percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr,
> > sechdrs[pcpuindex].sh_size);
> >
> > +#ifdef CONFIG_KGDB
> > + if ((err = add_modsects(mod, hdr, sechdrs, secstrings)) < 0) {
> > + goto nomodsectinfo;
> > + }
> > +#endif
> > +
> > err = module_finalize(hdr, sechdrs, mod);
> > if (err < 0)
> > goto cleanup;
> > @@ -1688,6 +1732,11 @@
> > arch_cleanup:
> > module_arch_cleanup(mod);
> > cleanup:
> > +
> > +#ifdef CONFIG_KGDB
> > +nomodsectinfo:
> > + vfree(mod->mod_sections);
> > +#endif
> > module_unload_free(mod);
> > module_free(mod, mod->module_init);
> > free_core:
> > @@ -1758,7 +1807,12 @@
> > if (ret < 0) {
> > /* Init routine failed: abort. Try to protect us from
> > buggy refcounters. */
> > +
> > mod->state = MODULE_STATE_GOING;
> > + down(¬ify_mutex);
> > + notifier_call_chain(&module_notify_list, MODULE_STATE_GOING,
> > + mod);
> > + up(¬ify_mutex);
> > synchronize_kernel();
> > if (mod->unsafe)
> > printk(KERN_ERR "%s: module is now stuck!\n",
> >
> >
> >
> > -------------------------------------------------------
> > This SF.Net email is sponsored by: IBM Linux Tutorials
> > Free Linux tutorial presented by Daniel Robbins, President and CEO of
> > GenToo technologies. Learn everything from fundamentals to system
> > administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click
> > _______________________________________________
> > Kgdb-bugreport mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
On Wednesday 17 Mar 2004 2:48 am, Rusty Russell wrote:
> On Fri, 2004-03-12 at 17:36, Amit S. Kale wrote:
> > Hi,
>
> Hi Amit,
>
> FYI: you would have received a quicker response if you'd CC'd me.
Hi Rusty,
Thanks.
Yep! I'll CC you on any further modules stuff.
>
> > It does following things:
> > 1. Adds MODULE_STATE_GONE to indicate that a module was removed. This is
> > differnent from MODULE_STATE_GOING. gdb needs to be notified of a module
> > event _after_ a module has been removed. Or else it'll still find the
> > module during a module list scan and will not remove it from its core.
>
> Makes sense.
>
> > 2. Defines a structure mod_section which stores module section names and
> > offsets preserved during loading of a module.
> >
> > 3. Adds a couple of fields to struct module to keep module section
> > information.
>
> Why not just set the section strings to SHF_ALLOC rather than copying
> (and possibly truncating) the names into your struct mod_section?
> struct mod_section is then simply void *addr; char *name;
How can I do that? Do I have to use objcopy on module files for this purpose?
-Amit
On Sat, 2004-03-20 at 02:06, Amit S. Kale wrote:
> On Wednesday 17 Mar 2004 2:48 am, Rusty Russell wrote:
> > Why not just set the section strings to SHF_ALLOC rather than copying
> > (and possibly truncating) the names into your struct mod_section?
> > struct mod_section is then simply void *addr; char *name;
>
> How can I do that? Do I have to use objcopy on module files for this purpose?
That'd be one way. But I was thinking you should add it in the loading
code the way CONFIG_KALLSYMS does for some other sections.
Cheers,
Rusty.
--
Anyone who quotes me in their signature is an idiot -- Rusty Russell