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authorGreg Banks <gnb@sgi.com>2009-04-01 07:28:15 +1100
committerJ. Bruce Fields <bfields@citi.umich.edu>2009-05-27 14:14:02 -0400
commitcf0a586cf41a1779edeee7562afb5d0ab46c7cf4 (patch)
tree3ede97c75e5adf69b19c397209dd60904ee26f4e /fs/nfsd/nfscache.c
parentfca4217c5bab31019b5247e977673c9fcc385f6b (diff)
knfsd: fix reply cache memory corruption
Fix a regression in the reply cache introduced when the code was converted to use proper Linux lists. When a new entry needs to be inserted, the case where all the entries are currently being used by threads is not correctly detected. This can result in memory corruption and a crash. In the current code this is an extremely unlikely corner case; it would require the machine to have 1024 nfsd threads and all of them to be busy at the same time. However, upcoming reply cache changes make this more likely; a crash due to this problem was actually observed in field. Signed-off-by: Greg Banks <gnb@sgi.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Diffstat (limited to 'fs/nfsd/nfscache.c')
-rw-r--r--fs/nfsd/nfscache.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index 6f0aa4989c61..4638635c5d87 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -174,8 +174,8 @@ nfsd_cache_lookup(struct svc_rqst *rqstp, int type)
}
}
- /* This should not happen */
- if (rp == NULL) {
+ /* All entries on the LRU are in-progress. This should not happen */
+ if (&rp->c_lru == &lru_head) {
static int complaints;
printk(KERN_WARNING "nfsd: all repcache entries locked!\n");