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| author | Mateusz Guzik <mjg@FreeBSD.org> | 2023-10-05 12:32:29 +0000 |
|---|---|---|
| committer | Mateusz Guzik <mjg@FreeBSD.org> | 2023-10-09 23:19:00 +0000 |
| commit | 99bfb6998b00ac8edd1395d76d199ddee62d24a0 (patch) | |
| tree | 9e281a0ac26b12eaa2e90ed990bfb400648dc0dd | |
| parent | b206bfb92c1f522c85ef1db44d42431e6c0d9334 (diff) | |
| download | src-99bfb6998b00ac8edd1395d76d199ddee62d24a0.tar.gz src-99bfb6998b00ac8edd1395d76d199ddee62d24a0.zip | |
vfs cache: denote a known bug in cache_remove_cnp
(cherry picked from commit cd2105d691f446f7dbddf5965d82b9e9103bc8d2)
| -rw-r--r-- | sys/kern/vfs_cache.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c index 44295e12ee59..115d0bdd3993 100644 --- a/sys/kern/vfs_cache.c +++ b/sys/kern/vfs_cache.c @@ -1747,6 +1747,15 @@ retry_dotdot: return (1); } + /* + * XXX note that access here is completely unlocked with no provisions + * to keep the hash allocated. If one is sufficiently unlucky a + * parallel cache resize can reallocate the hash, unmap backing pages + * and cause the empty check below to fault. + * + * Fixing this has epsilon priority, but can be done with no overhead + * for this codepath with sufficient effort. + */ hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp); blp = HASH2BUCKETLOCK(hash); retry: |