view src/os/unix/ngx_sunpro_x86.il @ 8106:8852f39311de

Fixed segfault when switching off master process during upgrade. Binary upgrades are not supported without master process, but it is, however, possible, that nginx running with master process is asked to upgrade binary, and the configuration file as available on disk at this time includes "master_process off;". If this happens, listening sockets inherited from the previous binary will have ls[i].previous set. But the old cycle on initial process startup, including startup after binary upgrade, is destroyed by ngx_init_cycle() once configuration parsing is complete. As a result, an attempt to dereference ls[i].previous in ngx_event_process_init() accesses already freed memory. Fix is to avoid looking into ls[i].previous if the old cycle is already freed. With this change it is also no longer needed to clear ls[i].previous in worker processes, so the relevant code was removed.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 23 Nov 2022 23:48:53 +0300
parents 2cd019520210
children
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/
/ Copyright (C) Igor Sysoev
/ Copyright (C) Nginx, Inc.
/

/ ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock,
/     ngx_atomic_uint_t old, ngx_atomic_uint_t set);
/
/ the arguments are passed on stack (%esp), 4(%esp), 8(%esp)

        .inline ngx_atomic_cmp_set,0
        movl      (%esp), %ecx
        movl      4(%esp), %eax
        movl      8(%esp), %edx
        lock
        cmpxchgl  %edx, (%ecx)
        setz      %al
        movzbl    %al, %eax
        .end


/ ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value,
/     ngx_atomic_int_t add);
/
/ the arguments are passed on stack (%esp), 4(%esp)

        .inline ngx_atomic_fetch_add,0
        movl      (%esp), %ecx
        movl      4(%esp), %eax
        lock
        xaddl     %eax, (%ecx)
        .end


/ ngx_cpu_pause()
/
/ the "rep; nop" is used instead of "pause" to avoid the "[ PAUSE ]" hardware
/ capability added by linker because Solaris/i386 does not know about it:
/
/ ld.so.1: nginx: fatal: hardware capability unsupported: 0x2000  [ PAUSE ]

        .inline ngx_cpu_pause,0
        rep; nop
        .end