diff options
| -rw-r--r-- | Documentation/fault-injection/provoke-crashes.txt | 38 | ||||
| -rw-r--r-- | drivers/misc/lkdtm.c | 472 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 5 |
3 files changed, 430 insertions, 85 deletions
diff --git a/Documentation/fault-injection/provoke-crashes.txt b/Documentation/fault-injection/provoke-crashes.txt new file mode 100644 index 0000000..7a9d3d8 --- /dev/null +++ b/Documentation/fault-injection/provoke-crashes.txt @@ -0,0 +1,38 @@ +The lkdtm module provides an interface to crash or injure the kernel at +predefined crashpoints to evaluate the reliability of crash dumps obtained +using different dumping solutions. The module uses KPROBEs to instrument +crashing points, but can also crash the kernel directly without KRPOBE +support. + + +You can provide the way either through module arguments when inserting +the module, or through a debugfs interface. + +Usage: insmod lkdtm.ko [recur_count={>0}] cpoint_name=<> cpoint_type=<> + [cpoint_count={>0}] + + recur_count : Recursion level for the stack overflow test. Default is 10. + + cpoint_name : Crash point where the kernel is to be crashed. It can be + one of INT_HARDWARE_ENTRY, INT_HW_IRQ_EN, INT_TASKLET_ENTRY, + FS_DEVRW, MEM_SWAPOUT, TIMERADD, SCSI_DISPATCH_CMD, + IDE_CORE_CP, DIRECT + + cpoint_type : Indicates the action to be taken on hitting the crash point. + It can be one of PANIC, BUG, EXCEPTION, LOOP, OVERFLOW, + CORRUPT_STACK, UNALIGNED_LOAD_STORE_WRITE, OVERWRITE_ALLOCATION, + WRITE_AFTER_FREE, + + cpoint_count : Indicates the number of times the crash point is to be hit + to trigger an action. The default is 10. + +You can also induce failures by mounting debugfs and writing the type to +<mountpoint>/provoke-crash/<crashpoint>. E.g., + + mount -t debugfs debugfs /mnt + echo EXCEPTION > /mnt/provoke-crash/INT_HARDWARE_ENTRY + + +A special file is `DIRECT' which will induce the crash directly without +KPROBE instrumentation. This mode is the only one available when the module +is built on a kernel without KPROBEs support. diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c index 3648b23..4a06483 100644 --- a/drivers/misc/lkdtm.c +++ b/drivers/misc/lkdtm.c @@ -26,21 +26,9 @@ * It is adapted from the Linux Kernel Dump Test Tool by * Fernando Luis Vazquez Cao <http://lkdtt.sourceforge.net> * - * Usage : insmod lkdtm.ko [recur_count={>0}] cpoint_name=<> cpoint_type=<> - * [cpoint_count={>0}] + * Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net> * - * recur_count : Recursion level for the stack overflow test. Default is 10. - * - * cpoint_name : Crash point where the kernel is to be crashed. It can be - * one of INT_HARDWARE_ENTRY, INT_HW_IRQ_EN, INT_TASKLET_ENTRY, - * FS_DEVRW, MEM_SWAPOUT, TIMERADD, SCSI_DISPATCH_CMD, - * IDE_CORE_CP - * - * cpoint_type : Indicates the action to be taken on hitting the crash point. - * It can be one of PANIC, BUG, EXCEPTION, LOOP, OVERFLOW - * - * cpoint_count : Indicates the number of times the crash point is to be hit - * to trigger an action. The default is 10. + * See Documentation/fault-injection/provoke-crashes.txt for instructions */ #include <linux/kernel.h> @@ -53,13 +41,12 @@ #include <linux/interrupt.h> #include <linux/hrtimer.h> #include <scsi/scsi_cmnd.h> +#include <linux/debugfs.h> #ifdef CONFIG_IDE #include <linux/ide.h> #endif -#define NUM_CPOINTS 8 -#define NUM_CPOINT_TYPES 5 #define DEFAULT_COUNT 10 #define REC_NUM_DEFAULT 10 @@ -72,7 +59,8 @@ enum cname { MEM_SWAPOUT, TIMERADD, SCSI_DISPATCH_CMD, - IDE_CORE_CP + IDE_CORE_CP, + DIRECT, }; enum ctype { @@ -81,7 +69,11 @@ enum ctype { BUG, EXCEPTION, LOOP, - OVERFLOW + OVERFLOW, + CORRUPT_STACK, + UNALIGNED_LOAD_STORE_WRITE, + OVERWRITE_ALLOCATION, + WRITE_AFTER_FREE, }; static char* cp_name[] = { @@ -92,7 +84,8 @@ static char* cp_name[] = { "MEM_SWAPOUT", "TIMERADD", "SCSI_DISPATCH_CMD", - "IDE_CORE_CP" + "IDE_CORE_CP", + "DIRECT", }; static char* cp_type[] = { @@ -100,7 +93,11 @@ static char* cp_type[] = { "BUG", "EXCEPTION", "LOOP", - "OVERFLOW" + "OVERFLOW", + "CORRUPT_STACK", + "UNALIGNED_LOAD_STORE_WRITE", + "OVERWRITE_ALLOCATION", + "WRITE_AFTER_FREE", }; static struct jprobe lkdtm; @@ -193,34 +190,66 @@ int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file, } #endif +/* Return the crashpoint number or NONE if the name is invalid */ +static enum ctype parse_cp_type(const char *what, size_t count) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(cp_type); i++) { + if (!strcmp(what, cp_type[i])) + return i + 1; + } + + return NONE; +} + +static const char *cp_type_to_str(enum ctype type) +{ + if (type == NONE || type < 0 || type > ARRAY_SIZE(cp_type)) + return "None"; + + return cp_type[type - 1]; +} + +static const char *cp_name_to_str(enum cname name) +{ + if (name == INVALID || name < 0 || name > ARRAY_SIZE(cp_name)) + return "INVALID"; + + return cp_name[name - 1]; +} + + static int lkdtm_parse_commandline(void) { int i; - if (cpoint_name == NULL || cpoint_type == NULL || - cpoint_count < 1 || recur_count < 1) + if (cpoint_count < 1 || recur_count < 1) return -EINVAL; - for (i = 0; i < NUM_CPOINTS; ++i) { + count = cpoint_count; + + /* No special parameters */ + if (!cpoint_type && !cpoint_name) + return 0; + + /* Neither or both of these need to be set */ + if (!cpoint_type || !cpoint_name) + return -EINVAL; + + cptype = parse_cp_type(cpoint_type, strlen(cpoint_type)); + if (cptype == NONE) + return -EINVAL; + + for (i = 0; i < ARRAY_SIZE(cp_name); i++) { if (!strcmp(cpoint_name, cp_name[i])) { cpoint = i + 1; - break; - } - } - - for (i = 0; i < NUM_CPOINT_TYPES; ++i) { - if (!strcmp(cpoint_type, cp_type[i])) { - cptype = i + 1; - break; + return 0; } } - if (cpoint == INVALID || cptype == NONE) - return -EINVAL; - - count = cpoint_count; - - return 0; + /* Could not find a valid crash point */ + return -EINVAL; } static int recursive_loop(int a) @@ -235,53 +264,92 @@ static int recursive_loop(int a) return recursive_loop(a); } -void lkdtm_handler(void) +static void lkdtm_do_action(enum ctype which) { - printk(KERN_INFO "lkdtm : Crash point %s of type %s hit\n", - cpoint_name, cpoint_type); - --count; + switch (which) { + case PANIC: + panic("dumptest"); + break; + case BUG: + BUG(); + break; + case EXCEPTION: + *((int *) 0) = 0; + break; + case LOOP: + for (;;) + ; + break; + case OVERFLOW: + (void) recursive_loop(0); + break; + case CORRUPT_STACK: { + volatile u32 data[8]; + volatile u32 *p = data; + + p[12] = 0x12345678; + break; + } + case UNALIGNED_LOAD_STORE_WRITE: { + static u8 data[5] __attribute__((aligned(4))) = {1, 2, + 3, 4, 5}; + u32 *p; + u32 val = 0x12345678; + + p = (u32 *)(data + 1); + if (*p == 0) + val = 0x87654321; + *p = val; + break; + } + case OVERWRITE_ALLOCATION: { + size_t len = 1020; + u32 *data = kmalloc(len, GFP_KERNEL); + + data[1024 / sizeof(u32)] = 0x12345678; + kfree(data); + break; + } + case WRITE_AFTER_FREE: { + size_t len = 1024; + u32 *data = kmalloc(len, GFP_KERNEL); + + kfree(data); + schedule(); + memset(data, 0x78, len); + break; + } + case NONE: + default: + break; + } + +} + +static void lkdtm_handler(void) +{ + count--; + printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n", + cp_name_to_str(cpoint), cp_type_to_str(cptype), count); if (count == 0) { - switch (cptype) { - case NONE: - break; - case PANIC: - printk(KERN_INFO "lkdtm : PANIC\n"); - panic("dumptest"); - break; - case BUG: - printk(KERN_INFO "lkdtm : BUG\n"); - BUG(); - break; - case EXCEPTION: - printk(KERN_INFO "lkdtm : EXCEPTION\n"); - *((int *) 0) = 0; - break; - case LOOP: - printk(KERN_INFO "lkdtm : LOOP\n"); - for (;;); - break; - case OVERFLOW: - printk(KERN_INFO "lkdtm : OVERFLOW\n"); - (void) recursive_loop(0); - break; - default: - break; - } + lkdtm_do_action(cptype); count = cpoint_count; } } -static int __init lkdtm_module_init(void) +static int lkdtm_register_cpoint(enum cname which) { int ret; - if (lkdtm_parse_commandline() == -EINVAL) { - printk(KERN_INFO "lkdtm : Invalid command\n"); - return -EINVAL; - } + cpoint = INVALID; + if (lkdtm.entry != NULL) + unregister_jprobe(&lkdtm); - switch (cpoint) { + switch (which) { + case DIRECT: + lkdtm_do_action(cptype); + return 0; case INT_HARDWARE_ENTRY: lkdtm.kp.symbol_name = "do_IRQ"; lkdtm.entry = (kprobe_opcode_t*) jp_do_irq; @@ -315,28 +383,268 @@ static int __init lkdtm_module_init(void) lkdtm.kp.symbol_name = "generic_ide_ioctl"; lkdtm.entry = (kprobe_opcode_t*) jp_generic_ide_ioctl; #else - printk(KERN_INFO "lkdtm : Crash point not available\n"); + printk(KERN_INFO "lkdtm: Crash point not available\n"); + return -EINVAL; #endif break; default: - printk(KERN_INFO "lkdtm : Invalid Crash Point\n"); - break; + printk(KERN_INFO "lkdtm: Invalid Crash Point\n"); + return -EINVAL; } + cpoint = which; if ((ret = register_jprobe(&lkdtm)) < 0) { - printk(KERN_INFO "lkdtm : Couldn't register jprobe\n"); - return ret; + printk(KERN_INFO "lkdtm: Couldn't register jprobe\n"); + cpoint = INVALID; + } + + return ret; +} + +static ssize_t do_register_entry(enum cname which, struct file *f, + const char __user *user_buf, size_t count, loff_t *off) +{ + char *buf; + int err; + + if (count >= PAGE_SIZE) + return -EINVAL; + + buf = (char *)__get_free_page(GFP_KERNEL); + if (!buf) + return -ENOMEM; + if (copy_from_user(buf, user_buf, count)) { + free_page((unsigned long) buf); + return -EFAULT; + } + /* NULL-terminate and remove enter */ + buf[count] = '\0'; + strim(buf); + + cptype = parse_cp_type(buf, count); + free_page((unsigned long) buf); + + if (cptype == NONE) + return -EINVAL; + + err = lkdtm_register_cpoint(which); + if (err < 0) + return err; + + *off += count; + + return count; +} + +/* Generic read callback that just prints out the available crash types */ +static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf, + size_t count, loff_t *off) +{ + char *buf; + int i, n, out; + + buf = (char *)__get_free_page(GFP_KERNEL); + + n = snprintf(buf, PAGE_SIZE, "Available crash types:\n"); + for (i = 0; i < ARRAY_SIZE(cp_type); i++) + n += snprintf(buf + n, PAGE_SIZE - n, "%s\n", cp_type[i]); + buf[n] = '\0'; + + out = simple_read_from_buffer(user_buf, count, off, + buf, n); + free_page((unsigned long) buf); + + return out; +} + +static int lkdtm_debugfs_open(struct inode *inode, struct file *file) +{ + return 0; +} + + +static ssize_t int_hardware_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(INT_HARDWARE_ENTRY, f, buf, count, off); +} + +static ssize_t int_hw_irq_en(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(INT_HW_IRQ_EN, f, buf, count, off); +} + +static ssize_t int_tasklet_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(INT_TASKLET_ENTRY, f, buf, count, off); +} + +static ssize_t fs_devrw_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(FS_DEVRW, f, buf, count, off); +} + +static ssize_t mem_swapout_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(MEM_SWAPOUT, f, buf, count, off); +} + +static ssize_t timeradd_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(TIMERADD, f, buf, count, off); +} + +static ssize_t scsi_dispatch_cmd_entry(struct file *f, + const char __user *buf, size_t count, loff_t *off) +{ + return do_register_entry(SCSI_DISPATCH_CMD, f, buf, count, off); +} + +static ssize_t ide_core_cp_entry(struct file *f, const char __user *buf, + size_t count, loff_t *off) +{ + return do_register_entry(IDE_CORE_CP, f, buf, count, off); +} + +/* Special entry to just crash directly. Available without KPROBEs */ +static ssize_t direct_entry(struct file *f, const char __user *user_buf, + size_t count, loff_t *off) +{ + enum ctype type; + char *buf; + + if (count >= PAGE_SIZE) + return -EINVAL; + if (count < 1) + return -EINVAL; + + buf = (char *)__get_free_page(GFP_KERNEL); + if (!buf) + return -ENOMEM; + if (copy_from_user(buf, user_buf, count)) { + free_page((unsigned long) buf); + return -EFAULT; + } + /* NULL-terminate and remove enter */ + buf[count] = '\0'; + strim(buf); + + type = parse_cp_type(buf, count); + free_page((unsigned long) buf); + if (type == NONE) + return -EINVAL; + + printk(KERN_INFO "lkdtm: Performing direct entry %s\n", + cp_type_to_str(type)); + lkdtm_do_action(type); + *off += count; + + return count; +} + +struct crash_entry { + const char *name; + const struct file_operations fops; +}; + +static const struct crash_entry crash_entries[] = { + {"DIRECT", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = direct_entry} }, + {"INT_HARDWARE_ENTRY", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = int_hardware_entry} }, + {"INT_HW_IRQ_EN", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = int_hw_irq_en} }, + {"INT_TASKLET_ENTRY", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = int_tasklet_entry} }, + {"FS_DEVRW", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = fs_devrw_entry} }, + {"MEM_SWAPOUT", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = mem_swapout_entry} }, + {"TIMERADD", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = timeradd_entry} }, + {"SCSI_DISPATCH_CMD", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = scsi_dispatch_cmd_entry} }, + {"IDE_CORE_CP", {.read = lkdtm_debugfs_read, + .open = lkdtm_debugfs_open, + .write = ide_core_cp_entry} }, +}; + +static struct dentry *lkdtm_debugfs_root; + +static int __init lkdtm_module_init(void) +{ + int ret = -EINVAL; + int n_debugfs_entries = 1; /* Assume only the direct entry */ + int i; + + /* Register debugfs interface */ + lkdtm_debugfs_root = debugfs_create_dir("provoke-crash", NULL); + if (!lkdtm_debugfs_root) { + printk(KERN_ERR "lkdtm: creating root dir failed\n"); + return -ENODEV; + } + +#ifdef CONFIG_KPROBES + n_debugfs_entries = ARRAY_SIZE(crash_entries); +#endif + + for (i = 0; i < n_debugfs_entries; i++) { + const struct crash_entry *cur = &crash_entries[i]; + struct dentry *de; + + de = debugfs_create_file(cur->name, 0644, lkdtm_debugfs_root, + NULL, &cur->fops); + if (de == NULL) { + printk(KERN_ERR "lkdtm: could not create %s\n", + cur->name); + goto out_err; + } + } + + if (lkdtm_parse_commandline() == -EINVAL) { + printk(KERN_INFO "lkdtm: Invalid command\n"); + goto out_err; + } + + if (cpoint != INVALID && cptype != NONE) { + ret = lkdtm_register_cpoint(cpoint); + if (ret < 0) { + printk(KERN_INFO "lkdtm: Invalid crash point %d\n", + cpoint); + goto out_err; + } + printk(KERN_INFO "lkdtm: Crash point %s of type %s registered\n", + cpoint_name, cpoint_type); + } else { + printk(KERN_INFO "lkdtm: No crash points registered, enable through debugfs\n"); } - printk(KERN_INFO "lkdtm : Crash point %s of type %s registered\n", - cpoint_name, cpoint_type); return 0; + +out_err: + debugfs_remove_recursive(lkdtm_debugfs_root); + return ret; } static void __exit lkdtm_module_exit(void) { - unregister_jprobe(&lkdtm); - printk(KERN_INFO "lkdtm : Crash point unregistered\n"); + debugfs_remove_recursive(lkdtm_debugfs_root); + + unregister_jprobe(&lkdtm); + printk(KERN_INFO "lkdtm: Crash point unregistered\n"); } module_init(lkdtm_module_init); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 5e3407d..b520ec1 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -864,8 +864,7 @@ config DEBUG_FORCE_WEAK_PER_CPU config LKDTM tristate "Linux Kernel Dump Test Tool Module" - depends on DEBUG_KERNEL - depends on KPROBES + depends on DEBUG_FS depends on BLOCK default n help @@ -876,7 +875,7 @@ config LKDTM called lkdtm. Documentation on how to use the module can be found in - drivers/misc/lkdtm.c + Documentation/fault-injection/provoke-crashes.txt config FAULT_INJECTION bool "Fault-injection framework" |
