source:
trunk/server/common/patches/openafs-afs_conn-overcounts.patch
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2649
Last change on this file since 2649 was 2649, checked in by andersk, 10 years ago | |
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File size: 2.5 KB |
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src/afs/afs_bypasscache.c
From 368fff3b2fef5b559ed6da016e1e9f0413b55552 Mon Sep 17 00:00:00 2001 From: Andrew Deason <adeason@sinenomine.net> Date: Sun, 14 Sep 2014 14:10:11 -0500 Subject: [PATCH] afs: Fix some afs_conn overcounts The usual pattern of using afs_Conn looks like this: do { tc = afs_Conn(...); if (tc) { code = /* ... */ } else { code = -1; } } while (afs_Analyze(...)); The afs_Analyze call, amongst other things, puts back the reference to the connection obtained from afs_Conn. If anything inside the do/while block exits that block without calling afs_Analyze or afs_PutConn, we will leak a reference to the conn. A few places currently do this, by jumping out of the loop with 'goto's. Specifically, in afs_dcache.c and afs_bypasscache.c. These locations currently leak references to our connection object (and to the underlying Rx connection object), which can cause problems over time. Specifically, this can cause a panic when the refcount overflows and becomes negative, causing a panic message that looks like: afs_PutConn: refcount imbalance 0xd34db33f -32768 To avoid this, make sure we afs_PutConn in these cases where we 'goto' out of the afs_Conn/afs_Analyze loop. Perhaps ideally we should cause afs_Analyze itself to be called in these situations, but for now just fix the problem with the least amount of impact possible. FIXES 131885 Change-Id: I3a52f8ccef24f01d04c02db0a4b711405360e323 --- src/afs/afs_bypasscache.c | 1 + src/afs/afs_dcache.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/src/afs/afs_bypasscache.c b/src/afs/afs_bypasscache.c index 744feb2..8fc6009 100644
a b afs_PrefetchNoCache(struct vcache *avc, 637 637 } else { 638 638 afs_warn("BYPASS: StartRXAFS_FetchData failed: %d\n", code); 639 639 unlock_and_release_pages(auio); 640 afs_PutConn(tc, rxconn, SHARED_LOCK); 640 641 goto done; 641 642 } 642 643 if (code == 0) { -
src/afs/afs_dcache.c
diff --git a/src/afs/afs_dcache.c b/src/afs/afs_dcache.c index dc1e039..a156e22 100644
a b afs_GetDCache(struct vcache *avc, afs_size_t abyte, 2399 2399 afs_PutDCache(tdc); 2400 2400 tdc = 0; 2401 2401 ReleaseReadLock(&avc->lock); 2402 2403 if (tc) { 2404 /* If we have a connection, we must put it back, 2405 * since afs_Analyze will not be called here. */ 2406 afs_PutConn(tc, rxconn, SHARED_LOCK); 2407 } 2408 2402 2409 slowPass = 1; 2403 2410 goto RetryGetDCache; 2404 2411 }
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