From: Ingo Molnar <mingo@elte.hu>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org
Subject: [patch] fix spinlock-debugging smp_processor_id() usage
Date: Tue, 20 Dec 2005 11:54:17 +0100 [thread overview]
Message-ID: <20051220105417.GA15120@elte.hu> (raw)
when a spinlock debugging check hits, we print the CPU number as an
informational thing - but there is no guarantee that preemption is off
at that point - hence we should use raw_smp_processor_id(). Otherwise
DEBUG_PREEMPT will print a warning. With the patch applied, the warning
goes away and only the spinlock-debugging info is printed.
it's an obvious bugfix, and i think it should get into 2.6.15.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Index: linux/lib/spinlock_debug.c
===================================================================
--- linux.orig/lib/spinlock_debug.c
+++ linux/lib/spinlock_debug.c
@@ -20,7 +20,8 @@ static void spin_bug(spinlock_t *lock, c
if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
owner = lock->owner;
printk("BUG: spinlock %s on CPU#%d, %s/%d\n",
- msg, smp_processor_id(), current->comm, current->pid);
+ msg, raw_smp_processor_id(),
+ current->comm, current->pid);
printk(" lock: %p, .magic: %08x, .owner: %s/%d, .owner_cpu: %d\n",
lock, lock->magic,
owner ? owner->comm : "<none>",
@@ -78,8 +79,8 @@ static void __spin_lock_debug(spinlock_t
if (print_once) {
print_once = 0;
printk("BUG: spinlock lockup on CPU#%d, %s/%d, %p\n",
- smp_processor_id(), current->comm, current->pid,
- lock);
+ raw_smp_processor_id(), current->comm,
+ current->pid, lock);
dump_stack();
}
}
@@ -120,7 +121,8 @@ static void rwlock_bug(rwlock_t *lock, c
if (xchg(&print_once, 0)) {
printk("BUG: rwlock %s on CPU#%d, %s/%d, %p\n", msg,
- smp_processor_id(), current->comm, current->pid, lock);
+ raw_smp_processor_id(), current->comm,
+ current->pid, lock);
dump_stack();
#ifdef CONFIG_SMP
/*
@@ -148,8 +150,8 @@ static void __read_lock_debug(rwlock_t *
if (print_once) {
print_once = 0;
printk("BUG: read-lock lockup on CPU#%d, %s/%d, %p\n",
- smp_processor_id(), current->comm, current->pid,
- lock);
+ raw_smp_processor_id(), current->comm,
+ current->pid, lock);
dump_stack();
}
}
@@ -220,8 +222,8 @@ static void __write_lock_debug(rwlock_t
if (print_once) {
print_once = 0;
printk("BUG: write-lock lockup on CPU#%d, %s/%d, %p\n",
- smp_processor_id(), current->comm, current->pid,
- lock);
+ raw_smp_processor_id(), current->comm,
+ current->pid, lock);
dump_stack();
}
}
reply other threads:[~2005-12-20 10:54 UTC|newest]
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