commit 40c4e7b73cf35f26125f7d2bb205e91274832ffc
author Maxim Dounin <mdounin@mdounin.ru> Wed Jun 05 19:44:22 2013 +0400
committer Maxim Dounin <mdounin@mdounin.ru> Wed Jun 05 19:44:22 2013 +0400
tree 28844394fc66f7b77db548606510e65697c389f5
parent 6b95320cf70baa57650e9f282592569912dc36ca

Valgrind: supressed complaints about uninitialized bytes.

Valgrind complains if we pass uninitialized memory to a syscall:

==36492== Syscall param sendmsg(msg.msg_iov[0]) points to uninitialised byte(s)
==36492==    at 0x6B5E6A: sendmsg (in /usr/lib/system/libsystem_kernel.dylib)
==36492==    by 0x10004288E: ngx_signal_worker_processes (ngx_process_cycle.c:527)
==36492==    by 0x1000417A7: ngx_master_process_cycle (ngx_process_cycle.c:203)
==36492==    by 0x100001F10: main (nginx.c:410)
==36492==  Address 0x7fff5fbff71c is on thread 1's stack

Even initialization of all members of the structure passed isn't enough, as
there is padding which still remains uninitialized and results in Valgrind
complaint.  Note there is no real problem here as data from uninitialized
memory isn't used.

src/http/ngx_http_file_cache.c

diff --git a/src/http/ngx_http_file_cache.c b/src/http/ngx_http_file_cache.c
index 6d94c50..eacca59 100644
--- a/src/http/ngx_http_file_cache.c
+++ b/src/http/ngx_http_file_cache.c
@@ -875,6 +875,8 @@
 
     c = r->cache;
 
+    ngx_memzero(h, sizeof(ngx_http_file_cache_header_t));
+
     h->valid_sec = c->valid_sec;
     h->last_modified = c->last_modified;
     h->date = c->date;

src/os/unix/ngx_process_cycle.c

diff --git a/src/os/unix/ngx_process_cycle.c b/src/os/unix/ngx_process_cycle.c
index dfdfae0..f937fb6 100644
--- a/src/os/unix/ngx_process_cycle.c
+++ b/src/os/unix/ngx_process_cycle.c
@@ -355,6 +355,8 @@
 
     ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0, "start worker processes");
 
+    ngx_memzero(&ch, sizeof(ngx_channel_t));
+
     ch.command = NGX_CMD_OPEN_CHANNEL;
 
     for (i = 0; i < n; i++) {
@@ -401,6 +403,8 @@
                       &ngx_cache_manager_ctx, "cache manager process",
                       respawn ? NGX_PROCESS_JUST_RESPAWN : NGX_PROCESS_RESPAWN);
 
+    ngx_memzero(&ch, sizeof(ngx_channel_t));
+
     ch.command = NGX_CMD_OPEN_CHANNEL;
     ch.pid = ngx_processes[ngx_process_slot].pid;
     ch.slot = ngx_process_slot;
@@ -460,6 +464,8 @@
     ngx_err_t      err;
     ngx_channel_t  ch;
 
+    ngx_memzero(&ch, sizeof(ngx_channel_t));
+
 #if (NGX_BROKEN_SCM_RIGHTS)
 
     ch.command = 0;
@@ -561,6 +567,8 @@
     ngx_channel_t     ch;
     ngx_core_conf_t  *ccf;
 
+    ngx_memzero(&ch, sizeof(ngx_channel_t));
+
     ch.command = NGX_CMD_CLOSE_CHANNEL;
     ch.fd = -1;