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authorBjörn Gustavsson <bjorn@erlang.org>2010-10-19 13:43:13 +0200
committerBjörn Gustavsson <bjorn@erlang.org>2010-10-20 12:02:08 +0200
commit7f82eddfaa3b89f734b4d58f1de92db86e5880cf (patch)
treed006dcb6f6c022ee875b32e75415c3793eb9cb7a /lib/kernel
parentc09fa792fad151f43cd3fa3d998b666a91badc5e (diff)
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Fix hang in on_load handlers in embedded mode
In embedded mode, all on_load handlers will be called after loading all modules but before starting any servers. Therefore, if an on_load handler calls any function in the code module that calls the code server (such as code:priv_dir/1), there will be a deadlock because the code server has not yet been started. Fix this problem by invoking the on_load handlers after having started most servers in the kernel application.
Diffstat (limited to 'lib/kernel')
-rw-r--r--lib/kernel/src/kernel.erl7
-rw-r--r--lib/kernel/test/code_SUITE_data/on_load_app-1.0/src/on_load_embedded.erl9
2 files changed, 16 insertions, 0 deletions
diff --git a/lib/kernel/src/kernel.erl b/lib/kernel/src/kernel.erl
index 92ee7b441a..d3b0f6c712 100644
--- a/lib/kernel/src/kernel.erl
+++ b/lib/kernel/src/kernel.erl
@@ -143,6 +143,13 @@ init(safe) ->
Boot = start_boot_server(),
DiskLog = start_disk_log(),
Pg2 = start_pg2(),
+
+ %% Run the on_load handlers for all modules that have been
+ %% loaded so far. Running them at this point means that
+ %% on_load handlers can safely call kernel processes
+ %% (and in particular call code:priv_dir/1 or code:lib_dir/1).
+ init:run_on_load_handlers(),
+
{ok, {SupFlags, Boot ++ DiskLog ++ Pg2}}.
get_code_args() ->
diff --git a/lib/kernel/test/code_SUITE_data/on_load_app-1.0/src/on_load_embedded.erl b/lib/kernel/test/code_SUITE_data/on_load_app-1.0/src/on_load_embedded.erl
index a39332f81d..b7fdd4d9ae 100644
--- a/lib/kernel/test/code_SUITE_data/on_load_app-1.0/src/on_load_embedded.erl
+++ b/lib/kernel/test/code_SUITE_data/on_load_app-1.0/src/on_load_embedded.erl
@@ -3,6 +3,15 @@
-on_load(run_me/0).
run_me() ->
+ %% An onload handler typically calls code:priv_dir/1
+ %% or code:lib_dir/1, so make sure that it works.
+ LibDir = code:lib_dir(on_load_app),
+ PrivDir = code:priv_dir(on_load_app),
+ LibDir = filename:dirname(PrivDir),
+ ModPath = code:which(?MODULE),
+ LibDir = filename:dirname(filename:dirname(ModPath)),
+
+ %% Start a process to remember that the on_load was called.
spawn(fun() ->
register(everything_is_fine, self()),
receive Any ->