Commit 9dcfe2c7 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

locking/refcounts: Change WARN() to WARN_ONCE() 



Linus noticed that the new refcount.h APIs used WARN(), which would turn
into a dmesg DoS if it triggers frequently on some buggy driver.

So make sure we only warn once. These warnings are never supposed to happen,
so it's typically not a problem to lose subsequent warnings.

Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/CA+55aFzbYUTZ=oqZ2YgDjY0C2_n6ODhTfqj6V+m5xWmDxsuB0w@mail.gmail.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 2d6be4ab

lib/refcount.c

+7 −7
Original line number Diff line number Diff line
@@ -58,7 +58,7 @@ bool refcount_add_not_zero(unsigned int i, refcount_t *r) 
		val = old;

	}



	WARN(new == UINT_MAX, "refcount_t: saturated; leaking memory.\n");

	WARN_ONCE(new == UINT_MAX, "refcount_t: saturated; leaking memory.\n");



	return true;

}
@@ -66,7 +66,7 @@ EXPORT_SYMBOL_GPL(refcount_add_not_zero); 


void refcount_add(unsigned int i, refcount_t *r)

{

	WARN(!refcount_add_not_zero(i, r), "refcount_t: addition on 0; use-after-free.\n");

	WARN_ONCE(!refcount_add_not_zero(i, r), "refcount_t: addition on 0; use-after-free.\n");

}

EXPORT_SYMBOL_GPL(refcount_add);
@@ -97,7 +97,7 @@ bool refcount_inc_not_zero(refcount_t *r) 
		val = old;

	}



	WARN(new == UINT_MAX, "refcount_t: saturated; leaking memory.\n");

	WARN_ONCE(new == UINT_MAX, "refcount_t: saturated; leaking memory.\n");



	return true;

}
@@ -111,7 +111,7 @@ EXPORT_SYMBOL_GPL(refcount_inc_not_zero); 
 */

void refcount_inc(refcount_t *r)

{

	WARN(!refcount_inc_not_zero(r), "refcount_t: increment on 0; use-after-free.\n");

	WARN_ONCE(!refcount_inc_not_zero(r), "refcount_t: increment on 0; use-after-free.\n");

}

EXPORT_SYMBOL_GPL(refcount_inc);
@@ -125,7 +125,7 @@ bool refcount_sub_and_test(unsigned int i, refcount_t *r) 


		new = val - i;

		if (new > val) {

			WARN(new > val, "refcount_t: underflow; use-after-free.\n");

			WARN_ONCE(new > val, "refcount_t: underflow; use-after-free.\n");

			return false;

		}
@@ -164,7 +164,7 @@ EXPORT_SYMBOL_GPL(refcount_dec_and_test); 


void refcount_dec(refcount_t *r)

{

	WARN(refcount_dec_and_test(r), "refcount_t: decrement hit 0; leaking memory.\n");

	WARN_ONCE(refcount_dec_and_test(r), "refcount_t: decrement hit 0; leaking memory.\n");

}

EXPORT_SYMBOL_GPL(refcount_dec);
@@ -204,7 +204,7 @@ bool refcount_dec_not_one(refcount_t *r) 


		new = val - 1;

		if (new > val) {

			WARN(new > val, "refcount_t: underflow; use-after-free.\n");

			WARN_ONCE(new > val, "refcount_t: underflow; use-after-free.\n");

			return true;

		}

CRA Git | Maintained and supported by SUSTech CRA and CCSE