Fix: increment buffer offset when failing to copy from user-space
[lttng-modules.git] / lttng-statedump-impl.c
index a707c775dd683a8b6dff99b53049349ddea43fdf..5511c7e82cf4da0a09056de5637ee4be9fd966a9 100644 (file)
@@ -28,7 +28,6 @@
 #include <linux/inetdevice.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
-#include <linux/fdtable.h>
 #include <linux/swap.h>
 #include <linux/wait.h>
 #include <linux/mutex.h>
@@ -43,7 +42,7 @@
 #include <wrapper/tracepoint.h>
 #include <wrapper/genhd.h>
 #include <wrapper/file.h>
-#include <wrapper/time.h>
+#include <wrapper/fdtable.h>
 
 #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
 #include <linux/irq.h>
 #define LTTNG_INSTRUMENTATION
 #include <instrumentation/events/lttng-module/lttng-statedump.h>
 
-DEFINE_TRACE(lttng_statedump_block_device);
-DEFINE_TRACE(lttng_statedump_end);
-DEFINE_TRACE(lttng_statedump_interrupt);
-DEFINE_TRACE(lttng_statedump_file_descriptor);
-DEFINE_TRACE(lttng_statedump_start);
-DEFINE_TRACE(lttng_statedump_process_state);
-DEFINE_TRACE(lttng_statedump_process_pid_ns);
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,6,0))
-DEFINE_TRACE(lttng_statedump_process_cgroup_ns);
+LTTNG_DEFINE_TRACE(lttng_statedump_block_device,
+       TP_PROTO(struct lttng_session *session,
+               dev_t dev, const char *diskname),
+       TP_ARGS(session, dev, diskname));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_end,
+       TP_PROTO(struct lttng_session *session),
+       TP_ARGS(session));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_interrupt,
+       TP_PROTO(struct lttng_session *session,
+               unsigned int irq, const char *chip_name,
+               struct irqaction *action),
+       TP_ARGS(session, irq, chip_name, action));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_file_descriptor,
+       TP_PROTO(struct lttng_session *session,
+               struct files_struct *files,
+               int fd, const char *filename,
+               unsigned int flags, fmode_t fmode),
+       TP_ARGS(session, files, fd, filename, flags, fmode));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_start,
+       TP_PROTO(struct lttng_session *session),
+       TP_ARGS(session));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_process_state,
+       TP_PROTO(struct lttng_session *session,
+               struct task_struct *p,
+               int type, int mode, int submode, int status,
+               struct files_struct *files),
+       TP_ARGS(session, p, type, mode, submode, status, files));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_process_pid_ns,
+       TP_PROTO(struct lttng_session *session,
+               struct task_struct *p,
+               struct pid_namespace *pid_ns),
+       TP_ARGS(session, p, pid_ns));
+
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
+LTTNG_DEFINE_TRACE(lttng_statedump_process_cgroup_ns,
+       TP_PROTO(struct lttng_session *session,
+               struct task_struct *p,
+               struct cgroup_namespace *cgroup_ns),
+       TP_ARGS(session, p, cgroup_ns));
 #endif
-DEFINE_TRACE(lttng_statedump_process_ipc_ns);
+
+LTTNG_DEFINE_TRACE(lttng_statedump_process_ipc_ns,
+       TP_PROTO(struct lttng_session *session,
+               struct task_struct *p,
+               struct ipc_namespace *ipc_ns),
+       TP_ARGS(session, p, ipc_ns));
+
 #ifndef LTTNG_MNT_NS_MISSING_HEADER
-DEFINE_TRACE(lttng_statedump_process_mnt_ns);
+LTTNG_DEFINE_TRACE(lttng_statedump_process_mnt_ns,
+       TP_PROTO(struct lttng_session *session,
+               struct task_struct *p,
+               struct mnt_namespace *mnt_ns),
+       TP_ARGS(session, p, mnt_ns));
 #endif
-DEFINE_TRACE(lttng_statedump_process_net_ns);
-DEFINE_TRACE(lttng_statedump_process_user_ns);
-DEFINE_TRACE(lttng_statedump_process_uts_ns);
-DEFINE_TRACE(lttng_statedump_network_interface);
+
+LTTNG_DEFINE_TRACE(lttng_statedump_process_net_ns,
+       TP_PROTO(struct lttng_session *session,
+               struct task_struct *p,
+               struct net *net_ns),
+       TP_ARGS(session, p, net_ns));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_process_user_ns,
+       TP_PROTO(struct lttng_session *session,
+               struct task_struct *p,
+               struct user_namespace *user_ns),
+       TP_ARGS(session, p, user_ns));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_process_uts_ns,
+       TP_PROTO(struct lttng_session *session,
+               struct task_struct *p,
+               struct uts_namespace *uts_ns),
+       TP_ARGS(session, p, uts_ns));
+
+LTTNG_DEFINE_TRACE(lttng_statedump_network_interface,
+       TP_PROTO(struct lttng_session *session,
+               struct net_device *dev, struct in_ifaddr *ifa),
+       TP_ARGS(session, dev, ifa));
+
 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
-DEFINE_TRACE(lttng_statedump_cpu_topology);
+LTTNG_DEFINE_TRACE(lttng_statedump_cpu_topology,
+       TP_PROTO(struct lttng_session *session, struct cpuinfo_x86 *c),
+       TP_ARGS(session, c));
 #endif
 
 struct lttng_fd_ctx {
        char *page;
        struct lttng_session *session;
-       struct task_struct *p;
        struct files_struct *files;
 };
 
@@ -122,6 +188,61 @@ enum lttng_process_status {
        LTTNG_DEAD = 7,
 };
 
+
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,11,0))
+
+#define LTTNG_PART_STRUCT_TYPE struct block_device
+
+static
+int lttng_get_part_name(struct gendisk *disk, struct block_device *part, char *name_buf)
+{
+       const char *p;
+
+       p = bdevname(part, name_buf);
+       if (!p)
+               return -ENOSYS;
+
+       return 0;
+}
+
+static
+dev_t lttng_get_part_devt(struct block_device *part)
+{
+       return part->bd_dev;
+}
+
+#else
+
+#define LTTNG_PART_STRUCT_TYPE struct hd_struct
+
+static
+int lttng_get_part_name(struct gendisk *disk, struct hd_struct *part, char *name_buf)
+{
+       const char *p;
+       struct block_device bdev;
+
+       /*
+        * Create a partial 'struct blockdevice' to use
+        * 'bdevname()' which is a simple wrapper over
+        * 'disk_name()' but has the honor to be EXPORT_SYMBOL.
+        */
+       bdev.bd_disk = disk;
+       bdev.bd_part = part;
+
+       p = bdevname(&bdev, name_buf);
+       if (!p)
+               return -ENOSYS;
+
+       return 0;
+}
+
+static
+dev_t lttng_get_part_devt(struct hd_struct *part)
+{
+       return part_devt(part);
+}
+#endif
+
 static
 int lttng_enumerate_block_devices(struct lttng_session *session)
 {
@@ -129,19 +250,23 @@ int lttng_enumerate_block_devices(struct lttng_session *session)
        struct device_type *ptr_disk_type;
        struct class_dev_iter iter;
        struct device *dev;
+       int ret = 0;
 
        ptr_block_class = wrapper_get_block_class();
-       if (!ptr_block_class)
-               return -ENOSYS;
+       if (!ptr_block_class) {
+               ret = -ENOSYS;
+               goto end;
+       }
        ptr_disk_type = wrapper_get_disk_type();
        if (!ptr_disk_type) {
-               return -ENOSYS;
+               ret = -ENOSYS;
+               goto end;
        }
        class_dev_iter_init(&iter, ptr_block_class, NULL, ptr_disk_type);
        while ((dev = class_dev_iter_next(&iter))) {
                struct disk_part_iter piter;
                struct gendisk *disk = dev_to_disk(dev);
-               struct hd_struct *part;
+               LTTNG_PART_STRUCT_TYPE *part;
 
                /*
                 * Don't show empty devices or things that have been
@@ -151,24 +276,32 @@ int lttng_enumerate_block_devices(struct lttng_session *session)
                    (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
                        continue;
 
-               disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
-               while ((part = disk_part_iter_next(&piter))) {
+               /*
+                * The original 'disk_part_iter_init' returns void, but our
+                * wrapper can fail to lookup the original symbol.
+                */
+               if (wrapper_disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0) < 0) {
+                       ret = -ENOSYS;
+                       goto iter_exit;
+               }
+
+               while ((part = wrapper_disk_part_iter_next(&piter))) {
                        char name_buf[BDEVNAME_SIZE];
-                       char *p;
 
-                       p = wrapper_disk_name(disk, part->partno, name_buf);
-                       if (!p) {
-                               disk_part_iter_exit(&piter);
-                               class_dev_iter_exit(&iter);
-                               return -ENOSYS;
+                       if (lttng_get_part_name(disk, part, name_buf) == -ENOSYS) {
+                               wrapper_disk_part_iter_exit(&piter);
+                               ret = -ENOSYS;
+                               goto iter_exit;
                        }
                        trace_lttng_statedump_block_device(session,
-                                       part_devt(part), name_buf);
+                                       lttng_get_part_devt(part), name_buf);
                }
-               disk_part_iter_exit(&piter);
+               wrapper_disk_part_iter_exit(&piter);
        }
+iter_exit:
        class_dev_iter_exit(&iter);
-       return 0;
+end:
+       return ret;
 }
 
 #ifdef CONFIG_INET
@@ -246,51 +379,27 @@ int lttng_dump_one_fd(const void *p, struct file *file, unsigned int fd)
 
                /* Make sure we give at least some info */
                spin_lock(&dentry->d_lock);
-               trace_lttng_statedump_file_descriptor(ctx->session, ctx->p, fd,
-                       dentry->d_name.name, flags, file->f_mode);
+               trace_lttng_statedump_file_descriptor(ctx->session,
+                       ctx->files, fd, dentry->d_name.name, flags,
+                       file->f_mode);
                spin_unlock(&dentry->d_lock);
                goto end;
        }
-       trace_lttng_statedump_file_descriptor(ctx->session, ctx->p, fd, s,
-               flags, file->f_mode);
+       trace_lttng_statedump_file_descriptor(ctx->session,
+               ctx->files, fd, s, flags, file->f_mode);
 end:
        return 0;
 }
 
+/* Called with task lock held. */
 static
-void lttng_enumerate_task_fd(struct lttng_session *session,
-               struct task_struct *p, char *tmp)
+void lttng_enumerate_files(struct lttng_session *session,
+               struct files_struct *files,
+               char *tmp)
 {
-       struct lttng_fd_ctx ctx = { .page = tmp, .session = session, .p = p };
-       struct files_struct *files;
+       struct lttng_fd_ctx ctx = { .page = tmp, .session = session, .files = files, };
 
-       task_lock(p);
-       files = p->files;
-       if (!files)
-               goto end;
-       ctx.files = files;
        lttng_iterate_fd(files, 0, lttng_dump_one_fd, &ctx);
-end:
-       task_unlock(p);
-}
-
-static
-int lttng_enumerate_file_descriptors(struct lttng_session *session)
-{
-       struct task_struct *p;
-       char *tmp;
-
-       tmp = (char *) __get_free_page(GFP_KERNEL);
-       if (!tmp)
-               return -ENOMEM;
-
-       /* Enumerate active file descriptors */
-       rcu_read_lock();
-       for_each_process(p)
-               lttng_enumerate_task_fd(session, p, tmp);
-       rcu_read_unlock();
-       free_page((unsigned long) tmp);
-       return 0;
 }
 
 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
@@ -425,17 +534,24 @@ void lttng_statedump_process_ns(struct lttng_session *session,
         */
        pid_ns = task_active_pid_ns(p);
        do {
-               trace_lttng_statedump_process_state(session,
-                       p, type, mode, submode, status, pid_ns);
                trace_lttng_statedump_process_pid_ns(session, p, pid_ns);
-               pid_ns = pid_ns->parent;
+               pid_ns = pid_ns ? pid_ns->parent : NULL;
        } while (pid_ns);
 
 
        user_ns = task_cred_xxx(p, user_ns);
        do {
                trace_lttng_statedump_process_user_ns(session, p, user_ns);
-               user_ns = user_ns->lttng_user_ns_parent;
+               /*
+                * trace_lttng_statedump_process_user_ns() internally
+                * checks whether user_ns is NULL. While this does not
+                * appear to be a possible return value for
+                * task_cred_xxx(), err on the safe side and check
+                * for NULL here as well to be consistent with the
+                * paranoid behavior of
+                * trace_lttng_statedump_process_user_ns().
+                */
+               user_ns = user_ns ? user_ns->lttng_user_ns_parent : NULL;
        } while (user_ns);
 
        /*
@@ -444,7 +560,7 @@ void lttng_statedump_process_ns(struct lttng_session *session,
         * "namespaces: Use task_lock and not rcu to protect nsproxy"
         * for details.
         */
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0) || \
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
                LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
                LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
                LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
@@ -454,7 +570,7 @@ void lttng_statedump_process_ns(struct lttng_session *session,
        proxy = task_nsproxy(p);
 #endif
        if (proxy) {
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,6,0))
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
                trace_lttng_statedump_process_cgroup_ns(session, p, proxy->cgroup_ns);
 #endif
                trace_lttng_statedump_process_ipc_ns(session, p, proxy->ipc_ns);
@@ -464,7 +580,7 @@ void lttng_statedump_process_ns(struct lttng_session *session,
                trace_lttng_statedump_process_net_ns(session, p, proxy->net_ns);
                trace_lttng_statedump_process_uts_ns(session, p, proxy->uts_ns);
        }
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0) || \
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
                LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
                LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
                LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
@@ -478,9 +594,16 @@ static
 int lttng_enumerate_process_states(struct lttng_session *session)
 {
        struct task_struct *g, *p;
+       char *tmp;
+
+       tmp = (char *) __get_free_page(GFP_KERNEL);
+       if (!tmp)
+               return -ENOMEM;
 
        rcu_read_lock();
        for_each_process(g) {
+               struct files_struct *prev_files = NULL;
+
                p = g;
                do {
                        enum lttng_execution_mode mode =
@@ -489,6 +612,7 @@ int lttng_enumerate_process_states(struct lttng_session *session)
                                LTTNG_UNKNOWN;
                        enum lttng_process_status status;
                        enum lttng_thread_type type;
+                       struct files_struct *files;
 
                        task_lock(p);
                        if (p->exit_state == EXIT_ZOMBIE)
@@ -523,13 +647,31 @@ int lttng_enumerate_process_states(struct lttng_session *session)
                                type = LTTNG_USER_THREAD;
                        else
                                type = LTTNG_KERNEL_THREAD;
+                       files = p->files;
+
+                       trace_lttng_statedump_process_state(session,
+                               p, type, mode, submode, status, files);
                        lttng_statedump_process_ns(session,
                                p, type, mode, submode, status);
+                       /*
+                        * As an optimisation for the common case, do not
+                        * repeat information for the same files_struct in
+                        * two consecutive threads. This is the common case
+                        * for threads sharing the same fd table. RCU guarantees
+                        * that the same files_struct pointer is not re-used
+                        * throughout processes/threads iteration.
+                        */
+                       if (files && files != prev_files) {
+                               lttng_enumerate_files(session, files, tmp);
+                               prev_files = files;
+                       }
                        task_unlock(p);
                } while_each_thread(g, p);
        }
        rcu_read_unlock();
 
+       free_page((unsigned long) tmp);
+
        return 0;
 }
 
@@ -548,9 +690,6 @@ int do_lttng_statedump(struct lttng_session *session)
 
        trace_lttng_statedump_start(session);
        ret = lttng_enumerate_process_states(session);
-       if (ret)
-               return ret;
-       ret = lttng_enumerate_file_descriptors(session);
        if (ret)
                return ret;
        /*
This page took 0.028404 seconds and 4 git commands to generate.