Commit 053c9598 authored by Chris Darroch's avatar Chris Darroch
Browse files

Make the worker and event MPMs not touch the scoreboard when 

handling a fork() failure.  The previous behaviour appears to have
been inherited from the prefork MPM, where is it appropriate.

The prefork MPM sets thread_limit to 1 and therefore each
child process has a single worker_score structure in the scoreboard's
array, i.e., ap_scoreboard_image->servers[slot][0].  In make_child(),
it sets this structure's status to SERVER_STARTING, and then does
a fork(); if the fork() fails, it resets the status to SERVER_DEAD.

The worker and event MPMs, by constrast, obviously use multiple
worker_score structures per child process.  They may also be
in use by worker threads from a previous generation at any particular
moment.  Therefore make_child() and the parent process in general
doesn't normally update them; make_child() doesn't set them all
to SERVER_STARTING before doing fork(), for example.

So, make_child() shouldn't set them to SERVER_DEAD if fork()
fails (and even if it should, it certainly shouldn't be just
updating the first one).



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@409693 13f79535-47bb-0310-9956-ffa450edef68
parent a27ec6ed

CHANGES

+3 −0
Changes for CHANGES: 3 added lines, 0 removed lines.
Original line number Diff line number Diff line
@@ -2,6 +2,9 @@ 
Changes with Apache 2.3.0

  [Remove entries to the current 2.0 and 2.2 section below, when backported]









  *) Worker and event MPMs: Remove improper scoreboard updates which were









     performed in the event of a fork() failure.  [Chris Darroch]

















  *) mod_cache: Make caching of reverse SSL proxies possible again. PR 39593.









     [Ruediger Pluem, Joe Orton]










































server/mpm/experimental/event/event.c



+5
−3



























Changes for server/mpm/experimental/event/event.c: 5 added lines, 3 removed lines.



Original line number
Diff line number
Diff line







@@ -1608,10 +1608,12 @@ static int make_child(server_rec * s, int slot)







        ap_log_error(APLOG_MARK, APLOG_ERR, errno, s,









                     "fork: Unable to fork new process");



















        /* fork didn't succeed. Fix the scoreboard or else









         * it will say SERVER_STARTING forever and ever









        /* fork didn't succeed.  There's no need to touch the scoreboard;









         * if we were trying to replace a failed child process, then









         * server_main_loop() marked its workers SERVER_DEAD, and if









         * we were trying to replace a child process that exited normally,









         * its worker_thread()s left SERVER_DEAD or SERVER_GRACEFUL behind.









         */









        ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD, NULL);



















        /* In case system resources are maxxed out, we don't want









           Apache running away with the CPU trying to fork over and


































server/mpm/worker/worker.c



+5
−4



























Changes for server/mpm/worker/worker.c: 5 added lines, 4 removed lines.



Original line number
Diff line number
Diff line







@@ -1285,11 +1285,12 @@ static int make_child(server_rec *s, int slot)







    if ((pid = fork()) == -1) {









        ap_log_error(APLOG_MARK, APLOG_ERR, errno, s,









                     "fork: Unable to fork new process");



















        /* fork didn't succeed. Fix the scoreboard or else









         * it will say SERVER_STARTING forever and ever









        /* fork didn't succeed.  There's no need to touch the scoreboard;









         * if we were trying to replace a failed child process, then









         * server_main_loop() marked its workers SERVER_DEAD, and if









         * we were trying to replace a child process that exited normally,









         * its worker_thread()s left SERVER_DEAD or SERVER_GRACEFUL behind.









         */









        ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD, NULL);



















        /* In case system resources are maxxed out, we don't want









           Apache running away with the CPU trying to fork over and