lby/lk
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[kernel] add code to check some overrun padding placed on the bottom of each threads' stack

Browse Source 
-Should impact context switch performance a bit
-Only enabled at LK_DEBUGLEVEL > 1
This commit is contained in:
Travis Geiselbrecht
2015-11-04 15:14:34 -08:00
parent 2d1e01cdd4
commit 814ca4e8a5
2 changed files with 47 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
include/kernel/thread.h
View File

@@ -38,6 +38,10 @@ __BEGIN_CDECLS;
/* debug-enable runtime checks */
#if LK_DEBUGLEVEL > 1
#define THREAD_STATS 1
#define THREAD_STACK_BOUNDS_CHECK 1
#ifndef THREAD_STACK_PADDING_SIZE
#define THREAD_STACK_PADDING_SIZE 256
#endif
#endif
enum thread_state {
@@ -62,11 +66,12 @@ enum thread_tls_list {
MAX_TLS_ENTRY
};
#define THREAD_FLAG_DETACHED 0x1
#define THREAD_FLAG_FREE_STACK 0x2
#define THREAD_FLAG_FREE_STRUCT 0x4
#define THREAD_FLAG_REAL_TIME 0x8
#define THREAD_FLAG_IDLE 0x10
#define THREAD_FLAG_DETACHED (1<<0)
#define THREAD_FLAG_FREE_STACK (1<<1)
#define THREAD_FLAG_FREE_STRUCT (1<<2)
#define THREAD_FLAG_REAL_TIME (1<<3)
#define THREAD_FLAG_IDLE (1<<4)
#define THREAD_FLAG_DEBUG_STACK_BOUNDS_CHECK (1<<5)
#define THREAD_MAGIC 'thrd'

38
kernel/thread.c
View File

@@ -50,6 +50,9 @@
struct thread_stats thread_stats[SMP_MAX_CPUS];
#endif
#define STACK_DEBUG_BYTE (0x99)
#define STACK_DEBUG_WORD (0x99999999)
/* global thread list */
static struct list_node thread_list;
@@ -161,6 +164,10 @@ thread_t *thread_create_etc(thread_t *t, const char *name, thread_start_routine
/* create the stack */
if (!stack) {
#if THREAD_STACK_BOUNDS_CHECK
stack_size += THREAD_STACK_PADDING_SIZE;
flags |= THREAD_FLAG_DEBUG_STACK_BOUNDS_CHECK;
#endif
t->stack = malloc(stack_size);
if (!t->stack) {
if (flags & THREAD_FLAG_FREE_STRUCT)
@@ -168,6 +175,9 @@ thread_t *thread_create_etc(thread_t *t, const char *name, thread_start_routine
return NULL;
}
flags |= THREAD_FLAG_FREE_STACK;
#if THREAD_STACK_BOUNDS_CHECK
memset(t->stack, STACK_DEBUG_BYTE, THREAD_STACK_PADDING_SIZE);
#endif
} else {
t->stack = stack;
}
@@ -387,9 +397,13 @@ void thread_exit(int retcode)
current_thread->magic = 0;
/* free its stack and the thread structure itself */
if (current_thread->flags & THREAD_FLAG_FREE_STACK && current_thread->stack)
if (current_thread->flags & THREAD_FLAG_FREE_STACK && current_thread->stack) {
heap_delayed_free(current_thread->stack);
/* make sure its not going to get a bounds check performed on the half-freed stack */
current_thread->flags &= ~THREAD_FLAG_DEBUG_STACK_BOUNDS_CHECK;
}
if (current_thread->flags & THREAD_FLAG_FREE_STRUCT)
heap_delayed_free(current_thread);
} else {
@@ -542,6 +556,23 @@ void thread_resched(void)
newthread->priority, newthread->flags);
#endif
#if THREAD_STACK_BOUNDS_CHECK
/* check that the old thread has not blown its stack just before pushing its context */
if (oldthread->flags & THREAD_FLAG_DEBUG_STACK_BOUNDS_CHECK) {
STATIC_ASSERT((THREAD_STACK_PADDING_SIZE % sizeof(uint32_t)) == 0);
uint32_t *s = (uint32_t *)oldthread->stack;
for (size_t i = 0; i < THREAD_STACK_PADDING_SIZE / sizeof(uint32_t); i++) {
if (unlikely(s[i] != STACK_DEBUG_WORD)) {
/* NOTE: will probably blow the stack harder here, but hopefully enough
* state exists to at least get some sort of debugging done.
*/
panic("stack overrun at %p: thread %p (%s), stack %p\n", &s[i],
oldthread, oldthread->name, oldthread->stack);
}
}
}
#endif
#ifdef WITH_LIB_UTHREAD
uthread_context_switch(oldthread, newthread);
#endif
@@ -925,6 +956,11 @@ void dump_all_threads(void)
THREAD_LOCK(state);
list_for_every_entry(&thread_list, t, thread_t, thread_list_node) {
if (t->magic != THREAD_MAGIC) {
dprintf(INFO, "bad magic on thread struct %p, aborting.\n", t);
hexdump(t, sizeof(thread_t));
break;
}
dump_thread(t);
}
THREAD_UNLOCK(state);