dtrace: fix for psinfo allocation during execve

Allocate the psinfo structure from a slab (alike other structures related to
the task_struct), and use kmalloc() for the argv and envp members (with size
limit to avoid allocation issues).

Orabug: 17407069
Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>

diff --git a/include/linux/dtrace_psinfo.h b/include/linux/dtrace_psinfo.h
index f9a149c94b0be08763a53c51ed32014138ad4854..8336aeb8918eb05392d2ea3b5408342d47157f89 100644 (file)
--- a/include/linux/dtrace_psinfo.h
+++ b/include/linux/dtrace_psinfo.h
@@ -4,6 +4,8 @@
 #define _LINUX_DTRACE_PSINFO_H_
 
 #define PR_PSARGS_SZ           80
+#define PR_ARGV_SZ             512
+#define PR_ENVP_SZ             512
 
 typedef struct dtrace_psinfo {
        union {

diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 36f3f2a62ce3bae27fa3dc49aa54e78f9e5bb285..479a770d44450d09013a01babbd655c74a5e41f8 100644 (file)
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -179,7 +179,7 @@ extern void mutex_unlock(struct mutex *lock);
 
 extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP)
 static inline int mutex_owned(struct mutex *lock)
 {
        return lock->owner == current;

diff --git a/kernel/dtrace/dtrace_cpu.c b/kernel/dtrace/dtrace_cpu.c
index 994fca15201bef52476906e1eb8be09ed660b866..7bc04e7ec91910bd3b8fbd9a46b26ee1baa0e76e 100644 (file)
--- a/kernel/dtrace/dtrace_cpu.c
+++ b/kernel/dtrace/dtrace_cpu.c
@@ -34,6 +34,7 @@ void dtrace_cpu_init(void)
                cpuc->cpuc_dcpc_intr_state = 0;
                cpuc->cpuc_dtrace_illval = 0;
                mutex_init(&cpuc->cpuc_pid_lock);
+
                cpuc->cpu_dtrace_regs = NULL;
                cpuc->cpu_dtrace_caller = 0;
                rwlock_init(&cpuc->cpu_ft_lock);

diff --git a/kernel/dtrace/dtrace_os.c b/kernel/dtrace/dtrace_os.c
index b50b5b73c007938be6b8604cc9708c4a827e71a2..496a2eaaa88b9f79570f002d3c2600e467a2c911 100644 (file)
--- a/kernel/dtrace/dtrace_os.c
+++ b/kernel/dtrace/dtrace_os.c
@@ -30,10 +30,12 @@
 /*---------------------------------------------------------------------------*\
 (* OS SPECIFIC DTRACE SETUP                                                  *)
 \*---------------------------------------------------------------------------*/
-struct module  *dtrace_kmod = NULL;
+struct module          *dtrace_kmod = NULL;
 EXPORT_SYMBOL(dtrace_kmod);
 
-int            dtrace_ustackdepth_max = 2048;
+int                    dtrace_ustackdepth_max = 2048;
+
+struct kmem_cache      *psinfo_cachep;
 
 void dtrace_os_init(void)
 {
@@ -52,6 +54,11 @@ void dtrace_os_init(void)
        dtrace_kmod->state = MODULE_STATE_LIVE;
        strlcpy(dtrace_kmod->name, "vmlinux", MODULE_NAME_LEN);
 
+       psinfo_cachep = kmem_cache_create("psinfo_cache",
+                               sizeof(dtrace_psinfo_t), 0,
+                               SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK,
+                               NULL);
+
        dtrace_sdt_register(dtrace_kmod);
 }
 EXPORT_SYMBOL(dtrace_os_init);
@@ -64,6 +71,7 @@ void dtrace_os_exit(void)
                return;
        }
 
+       kmem_cache_destroy(psinfo_cachep);
        kfree(dtrace_kmod);
        dtrace_kmod = NULL;
 }
@@ -80,7 +88,7 @@ dtrace_psinfo_t *dtrace_psinfo_alloc(struct task_struct *task)
        dtrace_psinfo_t         *psinfo;
        struct mm_struct        *mm;
 
-       psinfo = kzalloc(sizeof(dtrace_psinfo_t), GFP_KERNEL);
+       psinfo = kmem_cache_alloc(psinfo_cachep, GFP_KERNEL);
        if (psinfo == NULL)
                goto fail;
 
@@ -111,6 +119,7 @@ dtrace_psinfo_t *dtrace_psinfo_alloc(struct task_struct *task)
                /*
                 * Determine the number of arguments.
                 */
+               psinfo->argc = 0;
                for (p = (char *)mm->arg_start; p < (char *)mm->arg_end;
                     psinfo->argc++) {
                        size_t  l = strnlen(p, MAX_ARG_STRLEN);
@@ -121,18 +130,24 @@ dtrace_psinfo_t *dtrace_psinfo_alloc(struct task_struct *task)
                        p += l + 1;
                }
 
-               psinfo->argv = vmalloc((psinfo->argc + 1) * sizeof(char *));
+               /*
+                * Limit the number of stored argument pointers.
+                */
+               if ((len = psinfo->argc) >= PR_ARGV_SZ)
+                       len = PR_ARGV_SZ - 1;
+
+               psinfo->argv = kmalloc((len + 1) * sizeof(char *), GFP_KERNEL);
                if (psinfo->argv == NULL)
                        goto fail;
 
                /*
                 * Now populate the array of argument strings.
                 */
-               for (i = 0, p = (char *)mm->arg_start; i < psinfo->argc; i++) {
+               for (i = 0, p = (char *)mm->arg_start; i < len; i++) {
                        psinfo->argv[i] = p;
                        p += strnlen(p, MAX_ARG_STRLEN) + 1;
                }
-               psinfo->argv[psinfo->argc] = NULL;
+               psinfo->argv[len] = NULL;
 
                /*
                 * Determine the number of environment variables.
@@ -147,18 +162,24 @@ dtrace_psinfo_t *dtrace_psinfo_alloc(struct task_struct *task)
                        p += l + 1;
                }
 
-               psinfo->envp = vmalloc((envc + 1) * sizeof(char *));
+               /*
+                * Limit the number of stored environment pointers.
+                */
+               if ((len = envc) >= PR_ENVP_SZ)
+                       len = PR_ENVP_SZ - 1;
+
+               psinfo->envp = kmalloc((len + 1) * sizeof(char *), GFP_KERNEL);
                if (psinfo->envp == NULL)
                        goto fail;
 
                /*
                 * Now populate the array of environment variable strings.
                 */
-               for (i = 0, p = (char *)mm->env_start; i < envc; i++) {
+               for (i = 0, p = (char *)mm->env_start; i < len; i++) {
                        psinfo->envp[i] = p;
                        p += strnlen(p, MAX_ARG_STRLEN) + 1;
                }
-               psinfo->envp[envc] = NULL;
+               psinfo->envp[len] = NULL;
        }
 
        return psinfo;
@@ -166,12 +187,12 @@ dtrace_psinfo_t *dtrace_psinfo_alloc(struct task_struct *task)
 fail:
        pr_warning("%s: cannot allocate DTrace psinfo structure\n", __func__);
        if (psinfo) {
-               if (psinfo->argv == NULL)
-                       vfree(psinfo->argv);
-               if (psinfo->envp == NULL)
-                       vfree(psinfo->envp);
+               if (psinfo->argv)
+                       kfree(psinfo->argv);
+               if (psinfo->envp)
+                       kfree(psinfo->envp);
 
-               kfree(psinfo);
+               kmem_cache_free(psinfo_cachep, psinfo);
        }
 
        return NULL;
@@ -204,11 +225,11 @@ static void psinfo_cleaner(struct work_struct *work)
                dtrace_psinfo_t *next = psinfo->next;
 
                if (psinfo->argv)
-                       vfree(psinfo->argv);
+                       kfree(psinfo->argv);
                if (psinfo->envp)
-                       vfree(psinfo->envp);
+                       kfree(psinfo->envp);
 
-               kfree(psinfo);
+               kmem_cache_free(psinfo_cachep, psinfo);
                psinfo = next;
        }
 }