You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

Tom Lane f868a8143a Fix longstanding recursion hazard in sinval message processing. ... LockRelationOid and sibling routines supposed that, if our session already holds the lock they were asked to acquire, they could skip calling AcceptInvalidationMessages on the grounds that we must have already read any remote sinval messages issued against the relation being locked. This is normally true, but there's a critical special case where it's not: processing inside AcceptInvalidationMessages might attempt to access system relations, resulting in a recursive call to acquire a relation lock. Hence, if the outer call had acquired that same system catalog lock, we'd fall through, despite the possibility that there's an as-yet-unread sinval message for that system catalog. This could, for example, result in failure to access a system catalog or index that had just been processed by VACUUM FULL. This is the explanation for buildfarm failures we've been seeing intermittently for the past three months. The bug is far older than that, but commits a54e1f158 et al added a new recursion case within AcceptInvalidationMessages that is apparently easier to hit than any previous case. To fix this, we must not skip calling AcceptInvalidationMessages until we have *finished* a call to it since acquiring a relation lock, not merely acquired the lock. (There's already adequate logic inside AcceptInvalidationMessages to deal with being called recursively.) Fortunately, we can implement that at trivial cost, by adding a flag to LOCALLOCK hashtable entries that tracks whether we know we have completed such a call. There is an API hazard added by this patch for external callers of LockAcquire: if anything is testing for LOCKACQUIRE_ALREADY_HELD, it might be fooled by the new return code LOCKACQUIRE_ALREADY_CLEAR into thinking the lock wasn't already held. This should be a fail-soft condition, though, unless something very bizarre is being done in response to the test. Also, I added an additional output argument to LockAcquireExtended, assuming that that probably isn't called by any outside code given the very limited usefulness of its additional functionality. Back-patch to all supported branches. Discussion: https://postgr.es/m/12259.1532117714@sss.pgh.pa.us		7 years ago
..
backend	Fix longstanding recursion hazard in sinval message processing.	7 years ago
bin	Use C99 designated initializers for some structs	7 years ago
common	Require a C99-compliant snprintf(), and remove related workarounds.	8 years ago
fe_utils	Fix lexing of standard multi-character operators in edge cases.	7 years ago
include	Fix longstanding recursion hazard in sinval message processing.	7 years ago
interfaces	libpq: Change "options" dispchar to normal	7 years ago
makefiles	Refactor installation of extension headers.	7 years ago
pl	Use C99 designated initializers for some structs	7 years ago
port	Fix inconsistent argument naming.	7 years ago
template	…
test	Fully enforce uniqueness of constraint names.	7 years ago
timezone	Update time zone data files to tzdata release 2018e.	8 years ago
tools	Refactor dlopen() support	7 years ago
tutorial	Deduplicate "invalid input syntax" messages for various types.	8 years ago
.gitignore	…
DEVELOPERS	…
Makefile	Fix partial-build problems introduced by having more generated headers.	8 years ago
Makefile.global.in	Ensure we build generated headers at the start of some more cases.	8 years ago
Makefile.shlib	Prevent accidental linking of system-supplied copies of libpq.so etc.	8 years ago
nls-global.mk	…