Subject: track and print last unloaded module in the oops trace Date: Sun, 6 Jan 2008 15:19:46 -0800 From: Arjan van de Ven CC: rusty@rustcorp.com.au CC: ak@suse.de CC: mingo@elte.hu Based on a suggestion from Andi: In various cases, the unload of a module may leave some bad state around that causes a kernel crash AFTER a module is unloaded; and it's then hard to find which module caused that. This patch tracks the last unloaded module, and prints this as part of the module list in the oops trace. Right now, only the last 1 module is tracked; I expect that this is enough for the vast majority of cases where this information matters; if it turns out that tracking more is important, we can always extend it to that. Signed-off-by: Arjan van de Ven Signed-off-by: Rusty Russell --- kernel/module.c | 6 ++++++ 1 file changed, 6 insertions(+) Index: linux-2.6.24-rc6/kernel/module.c =================================================================== --- linux-2.6.24-rc6.orig/kernel/module.c +++ linux-2.6.24-rc6/kernel/module.c @@ -655,6 +655,8 @@ static void wait_for_zero_refcount(struc mutex_lock(&module_mutex); } +static char last_unloaded_module[MODULE_NAME_LEN+1]; + asmlinkage long sys_delete_module(const char __user *name_user, unsigned int flags) { @@ -721,6 +723,8 @@ sys_delete_module(const char __user *nam mod->exit(); mutex_lock(&module_mutex); } + /* Store the name of the last unloaded module for diagnostic purposes */ + sprintf(last_unloaded_module, mod->name); free_module(mod); out: @@ -2501,6 +2505,8 @@ void print_modules(void) printk("Modules linked in:"); list_for_each_entry(mod, &modules, list) printk(" %s%s", mod->name, module_flags(mod, buf)); + if (last_unloaded_module[0]) + printk(" [last unloaded: %s]", last_unloaded_module); printk("\n"); }