Mercurial > hg > nginx
view src/os/unix/rfork_thread.S @ 5245:711fa02afae8
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.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 05 Jun 2013 19:44:22 +0400 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <sys/syscall.h> #include <machine/asm.h> /* * rfork_thread(3) - rfork_thread(flags, stack, func, arg); */ #define KERNCALL int $0x80 ENTRY(rfork_thread) push %ebp mov %esp, %ebp push %esi mov 12(%ebp), %esi # the thread stack address sub $4, %esi mov 20(%ebp), %eax # the thread argument mov %eax, (%esi) sub $4, %esi mov 16(%ebp), %eax # the thread start address mov %eax, (%esi) push 8(%ebp) # rfork(2) flags push $0 mov $SYS_rfork, %eax KERNCALL jc error cmp $0, %edx jne child parent: add $8, %esp pop %esi leave ret child: mov %esi, %esp pop %eax call *%eax # call a thread start address ... add $4, %esp push %eax push $0 mov $SYS_exit, %eax # ... and exit(2) after a thread would return KERNCALL error: add $8, %esp pop %esi leave PIC_PROLOGUE /* libc's cerror: jmp PIC_PLT(HIDENAME(cerror)) */ push %eax call PIC_PLT(CNAME(__error)) pop %ecx PIC_EPILOGUE mov %ecx, (%eax) mov $-1, %eax mov $-1, %edx ret