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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH] net: print proper warning on dst underflow
Date: Tue, 24 Sep 2019 11:09:37 +0200	[thread overview]
Message-ID: <20190924090937.13001-1-Jason@zx2c4.com> (raw)

Proper warnings with stack traces make it much easier to figure out
what's doing the double free and create more meaningful bug reports from
users.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 net/core/dst.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/dst.c b/net/core/dst.c
index 1325316d9eab..193af526e908 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -172,7 +172,7 @@ void dst_release(struct dst_entry *dst)
 		int newrefcnt;
 
 		newrefcnt = atomic_dec_return(&dst->__refcnt);
-		if (unlikely(newrefcnt < 0))
+		if (WARN_ONCE(newrefcnt < 0, "dst_release underflow"))
 			net_warn_ratelimited("%s: dst:%p refcnt:%d\n",
 					     __func__, dst, newrefcnt);
 		if (!newrefcnt)
@@ -187,7 +187,7 @@ void dst_release_immediate(struct dst_entry *dst)
 		int newrefcnt;
 
 		newrefcnt = atomic_dec_return(&dst->__refcnt);
-		if (unlikely(newrefcnt < 0))
+		if (WARN_ONCE(newrefcnt < 0, "dst_release_immediate underflow"))
 			net_warn_ratelimited("%s: dst:%p refcnt:%d\n",
 					     __func__, dst, newrefcnt);
 		if (!newrefcnt)
-- 
2.21.0


             reply	other threads:[~2019-09-24  9:09 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-24  9:09 Jason A. Donenfeld [this message]
2019-09-26  7:06 ` [PATCH] net: print proper warning on dst underflow David Miller
2019-11-14  0:31 ` Kees Cook

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