Andriy Gapon 28bfd86184 8378 crash due to bp in-memory modification of nopwrite block ... illumos/illumos-gate@b7edcb9408 b7edcb9408 https://www.illumos.org/issues/8378 The problem is that zfs_get_data() supplies a stale zgd_bp to dmu_sync(), which we then nopwrite against. zfs_get_data() doesn't hold any DMU-related locks, so after it copies db_blkptr to zgd_bp, dbuf_write_ready() could change db_blkptr, and dbuf_write_done() could remove the dirty record. dmu_sync() then sees the stale BP and that the dbuf it not dirty, so it is eligible for nop-writing. The fix is for dmu_sync() to copy db_blkptr to zgd_bp after acquiring the db_mtx. We could still see a stale db_blkptr, but if it is stale then the dirty record will still exist and thus we won't attempt to nopwrite. Reviewed by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Approved by: Robert Mustacchi <rm@joyent.com> Author: Matthew Ahrens <mahrens@delphix.com>		2017-08-08 10:44:48 +00:00
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ztest.c	8378 crash due to bp in-memory modification of nopwrite block	2017-08-08 10:44:48 +00:00