From 6ff1cb355e628f8fc55fa2d01e269e5e1bbc2fe9 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Fri, 8 Dec 2006 02:39:43 -0800 Subject: [PATCH] fault-injection capabilities infrastructure This patch provides base functions implement to fault-injection capabilities. - The function should_fail() is taken from failmalloc-1.0 (http://www.nongnu.org/failmalloc/) [akpm@osdl.org: cleanups, comments, add __init] Cc: Signed-off-by: Akinobu Mita Signed-off-by: Don Mullis Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/fault-inject.c | 183 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 183 insertions(+) create mode 100644 lib/fault-inject.c (limited to 'lib/fault-inject.c') diff --git a/lib/fault-inject.c b/lib/fault-inject.c new file mode 100644 index 00000000000..a7cb3afd132 --- /dev/null +++ b/lib/fault-inject.c @@ -0,0 +1,183 @@ +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * setup_fault_attr() is a helper function for various __setup handlers, so it + * returns 0 on error, because that is what __setup handlers do. + */ +int __init setup_fault_attr(struct fault_attr *attr, char *str) +{ + unsigned long probability; + unsigned long interval; + int times; + int space; + + /* ",,," */ + if (sscanf(str, "%lu,%lu,%d,%d", + &interval, &probability, &space, ×) < 4) { + printk(KERN_WARNING + "FAULT_INJECTION: failed to parse arguments\n"); + return 0; + } + + attr->probability = probability; + attr->interval = interval; + atomic_set(&attr->times, times); + atomic_set(&attr->space, space); + + return 1; +} + +static void fail_dump(struct fault_attr *attr) +{ + if (attr->verbose > 0) + printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n"); + if (attr->verbose > 1) + dump_stack(); +} + +#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0) + +/* + * This code is stolen from failmalloc-1.0 + * http://www.nongnu.org/failmalloc/ + */ + +int should_fail(struct fault_attr *attr, ssize_t size) +{ + if (atomic_read(&attr->times) == 0) + return 0; + + if (atomic_read(&attr->space) > size) { + atomic_sub(size, &attr->space); + return 0; + } + + if (attr->interval > 1) { + attr->count++; + if (attr->count % attr->interval) + return 0; + } + + if (attr->probability > random32() % 100) + goto fail; + + return 0; + +fail: + fail_dump(attr); + + if (atomic_read(&attr->times) != -1) + atomic_dec_not_zero(&attr->times); + + return 1; +} + +#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS + +static void debugfs_ul_set(void *data, u64 val) +{ + *(unsigned long *)data = val; +} + +static u64 debugfs_ul_get(void *data) +{ + return *(unsigned long *)data; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); + +static struct dentry *debugfs_create_ul(const char *name, mode_t mode, + struct dentry *parent, unsigned long *value) +{ + return debugfs_create_file(name, mode, parent, value, &fops_ul); +} + +static void debugfs_atomic_t_set(void *data, u64 val) +{ + atomic_set((atomic_t *)data, val); +} + +static u64 debugfs_atomic_t_get(void *data) +{ + return atomic_read((atomic_t *)data); +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, + debugfs_atomic_t_set, "%lld\n"); + +static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode, + struct dentry *parent, atomic_t *value) +{ + return debugfs_create_file(name, mode, parent, value, &fops_atomic_t); +} + +void cleanup_fault_attr_dentries(struct fault_attr *attr) +{ + debugfs_remove(attr->dentries.probability_file); + attr->dentries.probability_file = NULL; + + debugfs_remove(attr->dentries.interval_file); + attr->dentries.interval_file = NULL; + + debugfs_remove(attr->dentries.times_file); + attr->dentries.times_file = NULL; + + debugfs_remove(attr->dentries.space_file); + attr->dentries.space_file = NULL; + + debugfs_remove(attr->dentries.verbose_file); + attr->dentries.verbose_file = NULL; + + if (attr->dentries.dir) + WARN_ON(!simple_empty(attr->dentries.dir)); + + debugfs_remove(attr->dentries.dir); + attr->dentries.dir = NULL; +} + +int init_fault_attr_dentries(struct fault_attr *attr, const char *name) +{ + mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; + struct dentry *dir; + + memset(&attr->dentries, 0, sizeof(attr->dentries)); + + dir = debugfs_create_dir(name, NULL); + if (!dir) + goto fail; + attr->dentries.dir = dir; + + attr->dentries.probability_file = + debugfs_create_ul("probability", mode, dir, &attr->probability); + + attr->dentries.interval_file = + debugfs_create_ul("interval", mode, dir, &attr->interval); + + attr->dentries.times_file = + debugfs_create_atomic_t("times", mode, dir, &attr->times); + + attr->dentries.space_file = + debugfs_create_atomic_t("space", mode, dir, &attr->space); + + attr->dentries.verbose_file = + debugfs_create_ul("verbose", mode, dir, &attr->verbose); + + if (!attr->dentries.probability_file || !attr->dentries.interval_file + || !attr->dentries.times_file || !attr->dentries.space_file + || !attr->dentries.verbose_file) + goto fail; + + return 0; +fail: + cleanup_fault_attr_dentries(attr); + return -ENOMEM; +} + +#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ -- cgit v1.2.3-70-g09d2 From f4f154fd920b2178382a6a24a236348e4429ebc1 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Fri, 8 Dec 2006 02:39:47 -0800 Subject: [PATCH] fault injection: process filtering for fault-injection capabilities This patch provides process filtering feature. The process filter allows failing only permitted processes by /proc//make-it-fail Please see the example that demostrates how to inject slab allocation failures into module init/cleanup code in Documentation/fault-injection/fault-injection.txt Signed-off-by: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/base.c | 65 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/fault-inject.h | 2 ++ include/linux/sched.h | 3 ++ lib/fault-inject.c | 17 +++++++++++- 4 files changed, 86 insertions(+), 1 deletion(-) (limited to 'lib/fault-inject.c') diff --git a/fs/proc/base.c b/fs/proc/base.c index a3b5074118a..fd959d5b5a8 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -853,6 +853,65 @@ static struct file_operations proc_seccomp_operations = { }; #endif /* CONFIG_SECCOMP */ +#ifdef CONFIG_FAULT_INJECTION +static ssize_t proc_fault_inject_read(struct file * file, char __user * buf, + size_t count, loff_t *ppos) +{ + struct task_struct *task = get_proc_task(file->f_dentry->d_inode); + char buffer[PROC_NUMBUF]; + size_t len; + int make_it_fail; + loff_t __ppos = *ppos; + + if (!task) + return -ESRCH; + make_it_fail = task->make_it_fail; + put_task_struct(task); + + len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail); + if (__ppos >= len) + return 0; + if (count > len-__ppos) + count = len-__ppos; + if (copy_to_user(buf, buffer + __ppos, count)) + return -EFAULT; + *ppos = __ppos + count; + return count; +} + +static ssize_t proc_fault_inject_write(struct file * file, + const char __user * buf, size_t count, loff_t *ppos) +{ + struct task_struct *task; + char buffer[PROC_NUMBUF], *end; + int make_it_fail; + + if (!capable(CAP_SYS_RESOURCE)) + return -EPERM; + memset(buffer, 0, sizeof(buffer)); + if (count > sizeof(buffer) - 1) + count = sizeof(buffer) - 1; + if (copy_from_user(buffer, buf, count)) + return -EFAULT; + make_it_fail = simple_strtol(buffer, &end, 0); + if (*end == '\n') + end++; + task = get_proc_task(file->f_dentry->d_inode); + if (!task) + return -ESRCH; + task->make_it_fail = make_it_fail; + put_task_struct(task); + if (end - buffer == 0) + return -EIO; + return end - buffer; +} + +static struct file_operations proc_fault_inject_operations = { + .read = proc_fault_inject_read, + .write = proc_fault_inject_write, +}; +#endif + static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd) { struct inode *inode = dentry->d_inode; @@ -1793,6 +1852,9 @@ static struct pid_entry tgid_base_stuff[] = { #ifdef CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, loginuid), #endif +#ifdef CONFIG_FAULT_INJECTION + REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject), +#endif }; static int proc_tgid_base_readdir(struct file * filp, @@ -2068,6 +2130,9 @@ static struct pid_entry tid_base_stuff[] = { #ifdef CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, loginuid), #endif +#ifdef CONFIG_FAULT_INJECTION + REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject), +#endif }; static int proc_tid_base_readdir(struct file * filp, diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h index 4df4902bc8d..a525f9b9f01 100644 --- a/include/linux/fault-inject.h +++ b/include/linux/fault-inject.h @@ -17,6 +17,7 @@ struct fault_attr { atomic_t times; atomic_t space; unsigned long verbose; + u32 task_filter; unsigned long count; @@ -30,6 +31,7 @@ struct fault_attr { struct dentry *times_file; struct dentry *space_file; struct dentry *verbose_file; + struct dentry *task_filter_file; } dentries; #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index f0317edea14..ad9c46071ff 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1045,6 +1045,9 @@ struct task_struct { #ifdef CONFIG_TASK_DELAY_ACCT struct task_delay_info *delays; #endif +#ifdef CONFIG_FAULT_INJECTION + int make_it_fail; +#endif }; static inline pid_t process_group(struct task_struct *tsk) diff --git a/lib/fault-inject.c b/lib/fault-inject.c index a7cb3afd132..03468609d70 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -5,6 +5,7 @@ #include #include #include +#include #include /* @@ -44,6 +45,11 @@ static void fail_dump(struct fault_attr *attr) #define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0) +static int fail_task(struct fault_attr *attr, struct task_struct *task) +{ + return !in_interrupt() && task->make_it_fail; +} + /* * This code is stolen from failmalloc-1.0 * http://www.nongnu.org/failmalloc/ @@ -51,6 +57,9 @@ static void fail_dump(struct fault_attr *attr) int should_fail(struct fault_attr *attr, ssize_t size) { + if (attr->task_filter && !fail_task(attr, current)) + return 0; + if (atomic_read(&attr->times) == 0) return 0; @@ -135,6 +144,9 @@ void cleanup_fault_attr_dentries(struct fault_attr *attr) debugfs_remove(attr->dentries.verbose_file); attr->dentries.verbose_file = NULL; + debugfs_remove(attr->dentries.task_filter_file); + attr->dentries.task_filter_file = NULL; + if (attr->dentries.dir) WARN_ON(!simple_empty(attr->dentries.dir)); @@ -169,9 +181,12 @@ int init_fault_attr_dentries(struct fault_attr *attr, const char *name) attr->dentries.verbose_file = debugfs_create_ul("verbose", mode, dir, &attr->verbose); + attr->dentries.task_filter_file = debugfs_create_bool("task-filter", + mode, dir, &attr->task_filter); + if (!attr->dentries.probability_file || !attr->dentries.interval_file || !attr->dentries.times_file || !attr->dentries.space_file - || !attr->dentries.verbose_file) + || !attr->dentries.verbose_file || !attr->dentries.task_filter_file) goto fail; return 0; -- cgit v1.2.3-70-g09d2 From 329409aeda064c4aff00c51f837fcd3bbdaeeba6 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Fri, 8 Dec 2006 02:39:48 -0800 Subject: [PATCH] fault injection: stacktrace filtering This patch provides stacktrace filtering feature. The stacktrace filter allows failing only for the caller you are interested in. For example someone may want to inject kmalloc() failures into only e100 module. they want to inject not only direct kmalloc() call, but also indirect allocation, too. - e100_poll --> netif_receive_skb --> packet_rcv_spkt --> skb_clone --> kmem_cache_alloc This patch enables to detect function calls like this by stacktrace and inject failures. The script Documentaion/fault-injection/failmodule.sh helps it. The range of text section of loaded e100 is expected to be [/sys/module/e100/sections/.text, /sys/module/e100/sections/.exit.text) So failmodule.sh stores these values into /debug/failslab/address-start and /debug/failslab/address-end. The maximum stacktrace depth is specified by /debug/failslab/stacktrace-depth. Please see the example that demonstrates how to inject slab allocation failures only for a specific module in Documentation/fault-injection/fault-injection.txt [dwm@meer.net: reject failure if any caller lies within specified range] Signed-off-by: Akinobu Mita Signed-off-by: Don Mullis Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/fault-injection/fault-injection.txt | 12 ++- include/linux/fault-inject.h | 12 +++ lib/Kconfig.debug | 5 + lib/fault-inject.c | 126 +++++++++++++++++++++- 4 files changed, 150 insertions(+), 5 deletions(-) (limited to 'lib/fault-inject.c') diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt index cf075c20eda..6d6e5ac5ea9 100644 --- a/Documentation/fault-injection/fault-injection.txt +++ b/Documentation/fault-injection/fault-injection.txt @@ -73,13 +73,17 @@ configuration of fault-injection capabilities. Any positive value limits failures to only processes indicated by /proc//make-it-fail==1. -- /debug/*/address-start: -- /debug/*/address-end: +- /debug/*/require-start: +- /debug/*/require-end: +- /debug/*/reject-start: +- /debug/*/reject-end: specifies the range of virtual addresses tested during stacktrace walking. Failure is injected only if some caller - in the walked stacktrace lies within this range. - Default is [0,ULONG_MAX) (whole of virtual address space). + in the walked stacktrace lies within the required range, and + none lies within the rejected range. + Default required range is [0,ULONG_MAX) (whole of virtual address space). + Default rejected range is [0,0). - /debug/*/stacktrace-depth: diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h index a525f9b9f01..9bb584e8939 100644 --- a/include/linux/fault-inject.h +++ b/include/linux/fault-inject.h @@ -18,6 +18,11 @@ struct fault_attr { atomic_t space; unsigned long verbose; u32 task_filter; + unsigned long stacktrace_depth; + unsigned long require_start; + unsigned long require_end; + unsigned long reject_start; + unsigned long reject_end; unsigned long count; @@ -32,6 +37,11 @@ struct fault_attr { struct dentry *space_file; struct dentry *verbose_file; struct dentry *task_filter_file; + struct dentry *stacktrace_depth_file; + struct dentry *require_start_file; + struct dentry *require_end_file; + struct dentry *reject_start_file; + struct dentry *reject_end_file; } dentries; #endif @@ -40,6 +50,8 @@ struct fault_attr { #define FAULT_ATTR_INITIALIZER { \ .interval = 1, \ .times = ATOMIC_INIT(1), \ + .require_end = ULONG_MAX, \ + .stacktrace_depth = 32, \ } #define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 336241bf0ce..1449ca1bf57 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -416,6 +416,11 @@ config LKDTM config FAULT_INJECTION bool + select STACKTRACE + select FRAME_POINTER + help + Provide fault-injection framework. + For more details, see Documentation/fault-injection/. config FAILSLAB bool "Fault-injection capabilitiy for kmalloc" diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 03468609d70..361c6e9cd77 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -6,6 +6,9 @@ #include #include #include +#include +#include +#include #include /* @@ -50,6 +53,86 @@ static int fail_task(struct fault_attr *attr, struct task_struct *task) return !in_interrupt() && task->make_it_fail; } +#ifdef CONFIG_STACK_UNWIND + +static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info, + void *arg) +{ + int depth; + struct fault_attr *attr = arg; + bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); + + for (depth = 0; depth < attr->stacktrace_depth + && unwind(info) == 0 && UNW_PC(info); depth++) { + if (arch_unw_user_mode(info)) + break; + if (attr->reject_start <= UNW_PC(info) && + UNW_PC(info) < attr->reject_end) + return 0; + if (attr->require_start <= UNW_PC(info) && + UNW_PC(info) < attr->require_end) + found = 1; + } + return found; +} + +static int fail_stacktrace(struct fault_attr *attr) +{ + struct unwind_frame_info info; + + return unwind_init_running(&info, fail_stacktrace_callback, attr); +} + +#elif defined(CONFIG_STACKTRACE) + +#define MAX_STACK_TRACE_DEPTH 32 + +static int fail_stacktrace(struct fault_attr *attr) +{ + struct stack_trace trace; + int depth = attr->stacktrace_depth; + unsigned long entries[MAX_STACK_TRACE_DEPTH]; + int n; + bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); + + if (depth == 0) + return found; + + trace.nr_entries = 0; + trace.entries = entries; + trace.max_entries = (depth < MAX_STACK_TRACE_DEPTH) ? + depth : MAX_STACK_TRACE_DEPTH; + trace.skip = 1; + trace.all_contexts = 0; + + save_stack_trace(&trace, NULL); + for (n = 0; n < trace.nr_entries; n++) { + if (attr->reject_start <= entries[n] && + entries[n] < attr->reject_end) + return 0; + if (attr->require_start <= entries[n] && + entries[n] < attr->require_end) + found = 1; + } + return found; +} + +#else + +static inline int fail_stacktrace(struct fault_attr *attr) +{ + static int firsttime = 1; + + if (firsttime) { + printk(KERN_WARNING + "This architecture does not implement save_stack_trace()\n"); + firsttime = 0; + } + return 0; +} + +#endif + /* * This code is stolen from failmalloc-1.0 * http://www.nongnu.org/failmalloc/ @@ -60,6 +143,9 @@ int should_fail(struct fault_attr *attr, ssize_t size) if (attr->task_filter && !fail_task(attr, current)) return 0; + if (!fail_stacktrace(attr)) + return 0; + if (atomic_read(&attr->times) == 0) return 0; @@ -147,6 +233,21 @@ void cleanup_fault_attr_dentries(struct fault_attr *attr) debugfs_remove(attr->dentries.task_filter_file); attr->dentries.task_filter_file = NULL; + debugfs_remove(attr->dentries.stacktrace_depth_file); + attr->dentries.stacktrace_depth_file = NULL; + + debugfs_remove(attr->dentries.require_start_file); + attr->dentries.require_start_file = NULL; + + debugfs_remove(attr->dentries.require_end_file); + attr->dentries.require_end_file = NULL; + + debugfs_remove(attr->dentries.reject_start_file); + attr->dentries.reject_start_file = NULL; + + debugfs_remove(attr->dentries.reject_end_file); + attr->dentries.reject_end_file = NULL; + if (attr->dentries.dir) WARN_ON(!simple_empty(attr->dentries.dir)); @@ -184,9 +285,32 @@ int init_fault_attr_dentries(struct fault_attr *attr, const char *name) attr->dentries.task_filter_file = debugfs_create_bool("task-filter", mode, dir, &attr->task_filter); + attr->dentries.stacktrace_depth_file = + debugfs_create_ul("stacktrace-depth", mode, dir, + &attr->stacktrace_depth); + + attr->dentries.require_start_file = + debugfs_create_ul("require-start", mode, dir, &attr->require_start); + + attr->dentries.require_end_file = + debugfs_create_ul("require-end", mode, dir, &attr->require_end); + + attr->dentries.reject_start_file = + debugfs_create_ul("reject-start", mode, dir, &attr->reject_start); + + attr->dentries.reject_end_file = + debugfs_create_ul("reject-end", mode, dir, &attr->reject_end); + + if (!attr->dentries.probability_file || !attr->dentries.interval_file || !attr->dentries.times_file || !attr->dentries.space_file - || !attr->dentries.verbose_file || !attr->dentries.task_filter_file) + || !attr->dentries.verbose_file || !attr->dentries.task_filter_file + || !attr->dentries.stacktrace_depth_file + || !attr->dentries.require_start_file + || !attr->dentries.require_end_file + || !attr->dentries.reject_start_file + || !attr->dentries.reject_end_file + ) goto fail; return 0; -- cgit v1.2.3-70-g09d2 From 08b3df2d16cbebf7d72c09dcbc071696c14d07e3 Mon Sep 17 00:00:00 2001 From: Don Mullis Date: Fri, 8 Dec 2006 02:39:51 -0800 Subject: [PATCH] fault-injection: Use bool-true-false throughout Use bool-true-false throughout. Signed-off-by: Don Mullis Cc: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fault-inject.h | 2 +- lib/fault-inject.c | 40 +++++++++++++++++++--------------------- 2 files changed, 20 insertions(+), 22 deletions(-) (limited to 'lib/fault-inject.c') diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h index 9bb584e8939..c77067916b7 100644 --- a/include/linux/fault-inject.h +++ b/include/linux/fault-inject.h @@ -57,7 +57,7 @@ struct fault_attr { #define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER int setup_fault_attr(struct fault_attr *attr, char *str); void should_fail_srandom(unsigned long entropy); -int should_fail(struct fault_attr *attr, ssize_t size); +bool should_fail(struct fault_attr *attr, ssize_t size); #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 361c6e9cd77..24478294034 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -48,7 +48,7 @@ static void fail_dump(struct fault_attr *attr) #define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0) -static int fail_task(struct fault_attr *attr, struct task_struct *task) +static bool fail_task(struct fault_attr *attr, struct task_struct *task) { return !in_interrupt() && task->make_it_fail; } @@ -68,15 +68,15 @@ static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info, break; if (attr->reject_start <= UNW_PC(info) && UNW_PC(info) < attr->reject_end) - return 0; + return false; if (attr->require_start <= UNW_PC(info) && UNW_PC(info) < attr->require_end) - found = 1; + found = true; } return found; } -static int fail_stacktrace(struct fault_attr *attr) +static bool fail_stacktrace(struct fault_attr *attr) { struct unwind_frame_info info; @@ -85,9 +85,7 @@ static int fail_stacktrace(struct fault_attr *attr) #elif defined(CONFIG_STACKTRACE) -#define MAX_STACK_TRACE_DEPTH 32 - -static int fail_stacktrace(struct fault_attr *attr) +static bool fail_stacktrace(struct fault_attr *attr) { struct stack_trace trace; int depth = attr->stacktrace_depth; @@ -109,26 +107,26 @@ static int fail_stacktrace(struct fault_attr *attr) for (n = 0; n < trace.nr_entries; n++) { if (attr->reject_start <= entries[n] && entries[n] < attr->reject_end) - return 0; + return false; if (attr->require_start <= entries[n] && entries[n] < attr->require_end) - found = 1; + found = true; } return found; } #else -static inline int fail_stacktrace(struct fault_attr *attr) +static inline bool fail_stacktrace(struct fault_attr *attr) { - static int firsttime = 1; + static bool firsttime = true; if (firsttime) { printk(KERN_WARNING "This architecture does not implement save_stack_trace()\n"); - firsttime = 0; + firsttime = false; } - return 0; + return false; } #endif @@ -138,32 +136,32 @@ static inline int fail_stacktrace(struct fault_attr *attr) * http://www.nongnu.org/failmalloc/ */ -int should_fail(struct fault_attr *attr, ssize_t size) +bool should_fail(struct fault_attr *attr, ssize_t size) { if (attr->task_filter && !fail_task(attr, current)) - return 0; + return false; if (!fail_stacktrace(attr)) - return 0; + return false; if (atomic_read(&attr->times) == 0) - return 0; + return false; if (atomic_read(&attr->space) > size) { atomic_sub(size, &attr->space); - return 0; + return false; } if (attr->interval > 1) { attr->count++; if (attr->count % attr->interval) - return 0; + return false; } if (attr->probability > random32() % 100) goto fail; - return 0; + return false; fail: fail_dump(attr); @@ -171,7 +169,7 @@ fail: if (atomic_read(&attr->times) != -1) atomic_dec_not_zero(&attr->times); - return 1; + return true; } #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS -- cgit v1.2.3-70-g09d2 From a124c28ef85d9b780c418b2c5d8f01cd6a06ff3e Mon Sep 17 00:00:00 2001 From: Don Mullis Date: Fri, 8 Dec 2006 02:39:52 -0800 Subject: [PATCH] fault-injection: Clamp debugfs stacktrace-depth to MAX_STACK_TRACE_DEPTH Clamp /debug/fail*/stacktrace-depth to MAX_STACK_TRACE_DEPTH. Ensures that a read of /debug/fail*/stacktrace-depth always returns a truthful answer. Signed-off-by: Don Mullis Cc: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/fault-inject.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) (limited to 'lib/fault-inject.c') diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 24478294034..5da665ac2d8 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -53,6 +53,8 @@ static bool fail_task(struct fault_attr *attr, struct task_struct *task) return !in_interrupt() && task->make_it_fail; } +#define MAX_STACK_TRACE_DEPTH 32 + #ifdef CONFIG_STACK_UNWIND static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info, @@ -98,8 +100,7 @@ static bool fail_stacktrace(struct fault_attr *attr) trace.nr_entries = 0; trace.entries = entries; - trace.max_entries = (depth < MAX_STACK_TRACE_DEPTH) ? - depth : MAX_STACK_TRACE_DEPTH; + trace.max_entries = depth; trace.skip = 1; trace.all_contexts = 0; @@ -179,6 +180,13 @@ static void debugfs_ul_set(void *data, u64 val) *(unsigned long *)data = val; } +static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val) +{ + *(unsigned long *)data = + val < MAX_STACK_TRACE_DEPTH ? + val : MAX_STACK_TRACE_DEPTH; +} + static u64 debugfs_ul_get(void *data) { return *(unsigned long *)data; @@ -192,6 +200,17 @@ static struct dentry *debugfs_create_ul(const char *name, mode_t mode, return debugfs_create_file(name, mode, parent, value, &fops_ul); } +DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get, + debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n"); + +static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH( + const char *name, mode_t mode, + struct dentry *parent, unsigned long *value) +{ + return debugfs_create_file(name, mode, parent, value, + &fops_ul_MAX_STACK_TRACE_DEPTH); +} + static void debugfs_atomic_t_set(void *data, u64 val) { atomic_set((atomic_t *)data, val); @@ -284,8 +303,8 @@ int init_fault_attr_dentries(struct fault_attr *attr, const char *name) mode, dir, &attr->task_filter); attr->dentries.stacktrace_depth_file = - debugfs_create_ul("stacktrace-depth", mode, dir, - &attr->stacktrace_depth); + debugfs_create_ul_MAX_STACK_TRACE_DEPTH( + "stacktrace-depth", mode, dir, &attr->stacktrace_depth); attr->dentries.require_start_file = debugfs_create_ul("require-start", mode, dir, &attr->require_start); -- cgit v1.2.3-70-g09d2 From f1729c28a37e4f11ea5d9f468ab26adadb1aadab Mon Sep 17 00:00:00 2001 From: Don Mullis Date: Fri, 8 Dec 2006 02:39:53 -0800 Subject: [PATCH] fault-injection: optimize and simplify should_fail() Trivial optimization and simplification of should_fail(). Do cheaper disqualification tests first (performance gain not quantified). Simplify logic; eliminate goto. Signed-off-by: Don Mullis Cc: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/fault-inject.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) (limited to 'lib/fault-inject.c') diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 5da665ac2d8..d143c0faf24 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -142,9 +142,6 @@ bool should_fail(struct fault_attr *attr, ssize_t size) if (attr->task_filter && !fail_task(attr, current)) return false; - if (!fail_stacktrace(attr)) - return false; - if (atomic_read(&attr->times) == 0) return false; @@ -159,12 +156,12 @@ bool should_fail(struct fault_attr *attr, ssize_t size) return false; } - if (attr->probability > random32() % 100) - goto fail; + if (attr->probability <= random32() % 100) + return false; - return false; + if (!fail_stacktrace(attr)) + return false; -fail: fail_dump(attr); if (atomic_read(&attr->times) != -1) -- cgit v1.2.3-70-g09d2