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Fixed a hypothetical bug: switch_sem_etc() was using thread_get_current_thread()

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in an error message without checking for a NULL pointer (which happens during
early boot, and even though it would be impossible to get there at that time,
it shouldn't be accidently copied to anywhere else this way).
Added a compile time option to monitor the last thread that successfully
acquired a semaphore (disabled, though, only enable it when needed).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@13998 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler
2005-08-20 20:13:05 +00:00
parent 200c6baf88
commit a10cd10b2b
1 changed files with 26 additions and 10 deletions
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src/system/kernel/sem.c
+26 -10
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@@ -28,12 +28,12 @@
//#define TRACE_SEM
#ifdef TRACE_SEM
# define TRACE(x) dprintf x
# define TRACE_BLOCK(x) dprintf x
#else
# define TRACE(x) ;
# define TRACE_BLOCK(x) ;
#endif
//#define DEBUG_LAST_ACQUIRER
struct sem_entry {
sem_id id;
spinlock lock; // protects only the id field when unused
@@ -44,6 +44,9 @@ struct sem_entry {
struct thread_queue queue;
char *name;
team_id owner; // if set to -1, means owned by a port
#ifdef DEBUG_LAST_ACQUIRER
thread_id last_acquirer;
#endif
} used;
// when slot unused
@@ -54,7 +57,7 @@ struct sem_entry {
} u;
};
// Todo: Compute based on the amount of available memory.
// ToDo: Compute based on the amount of available memory.
static int32 sMaxSems = 4096;
static int32 sUsedSems = 0;
@@ -104,6 +107,9 @@ dump_sem(struct sem_entry *sem)
kprintf("count: 0x%x\n", sem->u.used.count);
kprintf("queue: head %p tail %p\n", sem->u.used.queue.head,
sem->u.used.queue.tail);
#ifdef DEBUG_LAST_ACQUIRER
kprintf("last acquired by: 0x%lx\n", sem->u.used.last_acquirer);
#endif
} else {
kprintf("next: %p\n", sem->u.unused.next);
kprintf("next_id: %ld\n", sem->u.unused.next_id);
@@ -434,7 +440,7 @@ switch_sem_etc(sem_id semToBeReleased, sem_id id, int32 count,
int slot = id % sMaxSems;
int state;
status_t status = B_OK;
if (sSemsActive == false)
return B_NO_MORE_SEMS;
@@ -461,7 +467,8 @@ switch_sem_etc(sem_id semToBeReleased, sem_id id, int32 count,
// doesn't have any use outside the kernel
if ((flags & B_CHECK_PERMISSION) != 0
&& sSems[slot].u.used.owner == team_get_kernel_team_id()) {
dprintf("thread %ld tried to acquire kernel semaphore.\n", thread_get_current_thread()->id);
dprintf("thread %ld tried to acquire kernel semaphore.\n",
thread_get_current_thread_id());
status = B_NOT_ALLOWED;
goto err;
}
@@ -479,8 +486,8 @@ switch_sem_etc(sem_id semToBeReleased, sem_id id, int32 count,
timer timeout_timer; // stick it on the stack, since we may be blocking here
struct sem_timeout_args args;
TRACE_BLOCK(("acquire_sem_etc(id = %ld): block name = %s, thread = %p,"
" name = %s\n", id, sSems[slot].u.used.name, thread, thread->name));
TRACE(("acquire_sem_etc(id = %ld): block name = %s, thread = %p,"
" name = %s\n", id, sSems[slot].u.used.name, thread, thread->name));
// do a quick check to see if the thread has any pending signals
// this should catch most of the cases where the thread had a signal
@@ -558,12 +565,21 @@ switch_sem_etc(sem_id semToBeReleased, sem_id id, int32 count,
}
}
#ifdef DEBUG_LAST_ACQUIRER
if (thread->sem.acquire_status >= B_OK)
sSems[slot].u.used.last_acquirer = thread_get_current_thread_id();
#endif
restore_interrupts(state);
TRACE_BLOCK(("acquire_sem_etc(id = %ld): exit block name = %s, "
"thread = %p (%s)\n", id, sSems[slot].u.used.name, thread,
thread->name));
TRACE(("acquire_sem_etc(id = %ld): exit block name = %s, "
"thread = %p (%s)\n", id, sSems[slot].u.used.name, thread,
thread->name));
return thread->sem.acquire_status;
} else {
#ifdef DEBUG_LAST_ACQUIRER
sSems[slot].u.used.last_acquirer = thread_get_current_thread_id();
#endif
}
err: