Date: Wed, 30 Nov 2016 23:41:40 +0000 From: "rstone (Ryan Stone)" <phabric-noreply@FreeBSD.org> To: freebsd-net@freebsd.org Subject: [Differential] D8685: Fix a false positive in a buf_ring assert Message-ID: <26d1d780466ab064b7bd6bb0041f94be@localhost.localdomain> In-Reply-To: <differential-rev-PHID-DREV-7bpwu3y3lzsbz4zoj3jc-req@FreeBSD.org> References: <differential-rev-PHID-DREV-7bpwu3y3lzsbz4zoj3jc-req@FreeBSD.org>
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[-- Attachment #1 --] rstone updated this revision to Diff 22633. rstone added a comment. Ensure we don't walk off the end of the ring CHANGES SINCE LAST UPDATE https://reviews.freebsd.org/D8685?vs=22631&id=22633 REVISION DETAIL https://reviews.freebsd.org/D8685 AFFECTED FILES sys/sys/buf_ring.h CHANGE DETAILS diff --git a/sys/sys/buf_ring.h b/sys/sys/buf_ring.h --- a/sys/sys/buf_ring.h +++ b/sys/sys/buf_ring.h @@ -67,11 +67,13 @@ uint32_t prod_head, prod_next, cons_tail; #ifdef DEBUG_BUFRING int i; - for (i = br->br_cons_head; i != br->br_prod_head; - i = ((i + 1) & br->br_cons_mask)) - if(br->br_ring[i] == buf) - panic("buf=%p already enqueue at %d prod=%d cons=%d", - buf, i, br->br_prod_tail, br->br_cons_tail); + if (br->br_cons_head != br->br_prod_head) { + for (i = (br->br_cons_head + 1) & br->br_cons_mask; i != br->br_prod_head; + i = ((i + 1) & br->br_cons_mask)) + if(br->br_ring[i] == buf) + panic("buf=%p already enqueue at %d prod=%d cons=%d", + buf, i, br->br_prod_tail, br->br_cons_tail); + } #endif critical_enter(); do { EMAIL PREFERENCES https://reviews.freebsd.org/settings/panel/emailpreferences/ To: rstone Cc: hselasky, freebsd-net-list, emaste [-- Attachment #2 --] diff --git a/sys/sys/buf_ring.h b/sys/sys/buf_ring.h --- a/sys/sys/buf_ring.h +++ b/sys/sys/buf_ring.h @@ -67,11 +67,13 @@ uint32_t prod_head, prod_next, cons_tail; #ifdef DEBUG_BUFRING int i; - for (i = br->br_cons_head; i != br->br_prod_head; - i = ((i + 1) & br->br_cons_mask)) - if(br->br_ring[i] == buf) - panic("buf=%p already enqueue at %d prod=%d cons=%d", - buf, i, br->br_prod_tail, br->br_cons_tail); + if (br->br_cons_head != br->br_prod_head) { + for (i = (br->br_cons_head + 1) & br->br_cons_mask; i != br->br_prod_head; + i = ((i + 1) & br->br_cons_mask)) + if(br->br_ring[i] == buf) + panic("buf=%p already enqueue at %d prod=%d cons=%d", + buf, i, br->br_prod_tail, br->br_cons_tail); + } #endif critical_enter(); do {
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