From: Akinobu Mita 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 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(-) Index: 2.6-rc/fs/proc/base.c =================================================================== --- 2.6-rc.orig/fs/proc/base.c +++ 2.6-rc/fs/proc/base.c @@ -850,6 +850,65 @@ static struct file_operations proc_secco }; #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; @@ -1790,6 +1849,9 @@ 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, @@ -2064,6 +2126,9 @@ 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, Index: 2.6-rc/include/linux/sched.h =================================================================== --- 2.6-rc.orig/include/linux/sched.h +++ 2.6-rc/include/linux/sched.h @@ -1023,6 +1023,9 @@ 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) Index: 2.6-rc/include/linux/fault-inject.h =================================================================== --- 2.6-rc.orig/include/linux/fault-inject.h +++ 2.6-rc/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 Index: 2.6-rc/lib/fault-inject.c =================================================================== --- 2.6-rc.orig/lib/fault-inject.c +++ 2.6-rc/lib/fault-inject.c @@ -5,6 +5,7 @@ #include #include #include +#include #include int setup_fault_attr(struct fault_attr *attr, char *str) @@ -40,6 +41,11 @@ static void fail_dump(struct fault_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/ @@ -47,6 +53,9 @@ static void fail_dump(struct fault_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; @@ -131,6 +140,9 @@ void cleanup_fault_attr_dentries(struct 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)); @@ -165,9 +177,12 @@ int init_fault_attr_dentries(struct faul 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; 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