[NFS-Ganesha-Devel] Change in ...nfs-ganesha[next]: Fix lru_reap_chunk_impl racing with mdcache_lru_unref()

Malahal has uploaded this change for review. ( https://review.gerrithub.io/c/ffilz/nfs-ganesha/+/484339 ) Change subject: Fix lru_reap_chunk_impl racing with mdcache_lru_unref() ...................................................................... Fix lru_reap_chunk_impl racing with mdcache_lru_unref() lru_reap_chunk_impl() gets a ref on chunk->parent but its lru refcount could be zero by then. When a directory gets removed or one of its operations receives ESTALE error from FSAL, mdcache would eventually call mdcache_lru_unref() to free up the directory handle. mdcache_lru_unref() frees its chunks after the directory handle *refcount goes to zero*, so lru_reap_chunk_impl() could increment the directory handle refcount after it was already zero. This leads to the original thread that was freeing the directory handle as well as the thread calling lru_reap_chunk_impl() will try to free the same directory entry leading to use after free crashes. Change-Id: I4a77f10cbd4640e2aea7b9f05b2d47f2dfdb16e2 Signed-off-by: Malahal Naineni <malahal(a)us.ibm.com&gt; --- M src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_lru.c 1 file changed, 14 insertions(+), 21 deletions(-) git pull ssh://review.gerrithub.io:29418/ffilz/nfs-ganesha refs/changes/39/484339/1 -- To view, visit https://review.gerrithub.io/c/ffilz/nfs-ganesha/+/484339 To unsubscribe, or for help writing mail filters, visit https://review.gerrithub.io/settings Gerrit-Project: ffilz/nfs-ganesha Gerrit-Branch: next Gerrit-Change-Id: I4a77f10cbd4640e2aea7b9f05b2d47f2dfdb16e2 Gerrit-Change-Number: 484339 Gerrit-PatchSet: 1 Gerrit-Owner: Malahal <malahal(a)gmail.com&gt; Gerrit-MessageType: newchange