diff options
Diffstat (limited to 'backport-Skip-unusable-entries-in-first-pass-in-prune_cache.patch')
| -rw-r--r-- | backport-Skip-unusable-entries-in-first-pass-in-prune_cache.patch | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/backport-Skip-unusable-entries-in-first-pass-in-prune_cache.patch b/backport-Skip-unusable-entries-in-first-pass-in-prune_cache.patch new file mode 100644 index 0000000..dcd3609 --- /dev/null +++ b/backport-Skip-unusable-entries-in-first-pass-in-prune_cache.patch @@ -0,0 +1,93 @@ +From c00b984fcd53f679ca2dafcd1aee2c89836e6e73 Mon Sep 17 00:00:00 2001 +From: Florian Weimer <fweimer@redhat.com> +Date: Tue, 29 Aug 2023 08:28:31 +0200 +Subject: [PATCH] nscd: Skip unusable entries in first pass in prune_cache (bug + 30800) + +Previously, if an entry was marked unusable for any reason, but had +not timed out yet, the assert would trigger. + +One way to get into such state is if a data change is detected during +re-validation of an entry. This causes the entry to be marked as not +usable. If exits nscd soon after that, then the clock jumps +backwards, and nscd restarted, the cache re-validation run after +startup triggers the removed assert. + +The change is more complicated than just the removal of the assert +because entries marked as not usable should be garbage-collected in +the second pass. To make this happen, it is necessary to update some +book-keeping data. + +Reviewed-by: DJ Delorie <dj@redhat.com> + +Conflict:NA +Reference:https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=c00b984fcd53f679ca2dafcd1aee2c89836e6e73 + +--- + nscd/cache.c | 25 +++++++++++-------------- + 1 file changed, 11 insertions(+), 14 deletions(-) + +diff --git a/nscd/cache.c b/nscd/cache.c +index 78b22697..ac5902ae 100644 +--- a/nscd/cache.c ++++ b/nscd/cache.c +@@ -371,8 +371,11 @@ prune_cache (struct database_dyn *table, time_t now, int fd) + serv2str[runp->type], str, dh->timeout); + } + +- /* Check whether the entry timed out. */ +- if (dh->timeout < now) ++ /* Check whether the entry timed out. Timed out entries ++ will be revalidated. For unusable records, it is still ++ necessary to record that the bucket needs to be scanned ++ again below. */ ++ if (dh->timeout < now || !dh->usable) + { + /* This hash bucket could contain entries which need to + be looked at. */ +@@ -384,7 +387,7 @@ prune_cache (struct database_dyn *table, time_t now, int fd) + /* We only have to look at the data of the first entries + since the count information is kept in the data part + which is shared. */ +- if (runp->first) ++ if (runp->first && dh->usable) + { + + /* At this point there are two choices: we reload the +@@ -400,9 +403,6 @@ prune_cache (struct database_dyn *table, time_t now, int fd) + { + /* Remove the value. */ + dh->usable = false; +- +- /* We definitely have some garbage entries now. */ +- any = true; + } + else + { +@@ -414,18 +414,15 @@ prune_cache (struct database_dyn *table, time_t now, int fd) + + time_t timeout = readdfcts[runp->type] (table, runp, dh); + next_timeout = MIN (next_timeout, timeout); +- +- /* If the entry has been replaced, we might need +- cleanup. */ +- any |= !dh->usable; + } + } ++ ++ /* If the entry has been replaced, we might need cleanup. */ ++ any |= !dh->usable; + } + else +- { +- assert (dh->usable); +- next_timeout = MIN (next_timeout, dh->timeout); +- } ++ /* Entry has not timed out and is usable. */ ++ next_timeout = MIN (next_timeout, dh->timeout); + + run = runp->next; + } +-- +2.33.0 + |