Fix race in dsm_unpin_segment() when handles are reused. Teach dsm_unpin_segment() to skip segments that are in the process of being destroyed by another backend, when searching for a handle. Such a segment cannot possibly be the one we are looking for, even if its handle matches. Another slot might hold a recently created segment that has the same handle value by coincidence, and we need to keep searching for that one.
The bug caused rare "cannot unpin a segment that is not pinned" errors on 10 and 11. Similar to commit 6c0fb941 for dsm_attach(). Back-patch to 10, where dsm_unpin_segment() landed. Author: Thomas Munro Reported-by: Justin Pryzby Tested-by: Justin Pryzby (along with other recent DSA/DSM fixes) Discussion: https://postgr.es/m/20190216023854.gf30...@telsasoft.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/0b55aaacec313c309e21f63d9ff5733c3f8ab813 Modified Files -------------- src/backend/storage/ipc/dsm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)