This new option, when set, will cause the callers of pool_alloc() and
pool_free() to be recorded into an extra area in the pool that is expected
to be helpful for later inspection (e.g. in core dumps). For example it
may help figure that an object was released to a pool with some sub-fields
not yet released or that a use-after-free happened after releasing it,
with an immediate indication about the exact line of code that released
it (possibly an error path).
This only works with the per-thread cache, and even objects refilled from
the shared pool directly into the thread-local cache will have a NULL
there. That's not an issue since these objects have not yet been freed.
It's worth noting that pool_alloc_nocache() continues not to set any
caller pointer (e.g. when the cache is empty) because that would require
a possibly undesirable API change.
The extra cost is minimal (one pointer per object) and this completes
well with DEBUG_POOL_INTEGRITY.
When enabled, objects picked from the cache are checked for corruption
by comparing their contents against a pattern that was placed when they
were inserted into the cache. Objects are also allocated in the reverse
order, from the oldest one to the most recent, so as to maximize the
ability to detect such a corruption. The goal is to detect writes after
free (or possibly hardware memory corruptions). Contrary to DEBUG_UAF
this cannot detect reads after free, but may possibly detect later
corruptions and will not consume extra memory. The CPU usage will
increase a bit due to the cost of filling/checking the area and for the
preference for cold cache instead of hot cache, though not as much as
with DEBUG_UAF. This option is meant to be usable in production.
The purpose here is to explain how memory pools work, what their
architecture is depending on the build options (4 possible combinations),
and how the various build options affect their behavior.
Two pool-specific macros that were previously documented in initcalls
were moved to pools.txt.
Another non-trivial part that is often needed. Exported functions
and flags available to applications were documented as well as some
restrictions and falltraps.
This one was missing. It should be easier to use now. It is obvious that
some functions are missing, and it looks like ist2str() and istpad() are
exactly the same.
Released version 2.5-dev13 with the following main changes :
- SCRIPTS: git-show-backports: re-enable file-based filtering
- MINOR: jwt: Make invalid static JWT algorithms an error in `jwt_verify` converter
- MINOR: mux-h2: add trace on extended connect usage
- BUG/MEDIUM: mux-h2: reject upgrade if no RFC8441 support
- MINOR: stream/mux: implement websocket stream flag
- MINOR: connection: implement function to update ALPN
- MINOR: connection: add alternative mux_ops param for conn_install_mux_be
- MEDIUM: server/backend: implement websocket protocol selection
- MINOR: server: add ws keyword
- BUG/MINOR: resolvers: fix sent messages were counted twice
- BUG/MINOR: resolvers: throw log message if trash not large enough for query
- MINOR: resolvers/dns: split dns and resolver counters in dns_counter struct
- MEDIUM: resolvers: rename dns extra counters to resolvers extra counters
- BUG/MINOR: jwt: Fix jwt_parse_alg incorrectly returning JWS_ALG_NONE
- DOC: add QUIC instruction in INSTALL
- CLEANUP: halog: Remove dead stores
- DEV: coccinelle: Add ha_free.cocci
- CLEANUP: Apply ha_free.cocci
- DEV: coccinelle: Add rule to use `istnext()` where possible
- CLEANUP: Apply ist.cocci
- REGTESTS: Use `feature cmd` for 2.5+ tests (2)
- DOC: internals: move some API definitions to an "api" subdirectory
- MINOR: quic: Allocate listener RX buffers
- CLEANUP: quic: Remove useless code
- MINOR: quic: Enhance the listener RX buffering part
- MINOR: quic: Remove a useless lock for CRYPTO frames
- MINOR: quic: Use QUIC_LOCK QUIC specific lock label.
- MINOR: backend: Get client dst address to set the server's one only if needful
- MINOR: compression: Warn for 'compression offload' in defaults sections
- MEDIUM: connection: rename fc_conn_err and bc_conn_err to fc_err and bc_err
- DOC: configuration: move the default log formats to their own section
- MINOR: ssl: make the ssl_fc_sni() sample-fetch function always available
- MEDIUM: log: add the client's SNI to the default HTTPS log format
- DOC: config: add an example of reasonably complete error-log-format
- DOC: config: move error-log-format before custom log format
It's not always easy to figure that there are some docs on internal API
stuff, let's move them to their own directory. There's a diagram for
lists that could be placed there but instead would deserve a greppable
description for quick lookups, so it was not moved there.
