I found the problem:
* init uses waitpid(-1,,), thus the __WALL flag is not set
* without __WALL, only processes with exit_signal == SIGCHLD are reaped
* it's impossible for user space processes to die with another
exit_signal, forget_original_parent changes the exit_signal back to
SIGCHLD ("We dont want people slaying init"), and init itself doesn't
use clone.
* kernel threads can die with an arbitrary exit_signal.
Alan, which fix would you prefer:
* init could use wait3 and set __WALL.
* all kernel thread users could set SIGCHLD. Some already do that
(__call_usermodehelper).
* the kernel_thread implementations could force the exit signal to
SIGCHLD.
I'd prefer the last version.
The attached patch is tested with i386. The alpha, parisc and ppc
assember changes are guessed.
-- Manfred --------------DE1890DE7E5BD7D6D7A75795 Content-Type: text/plain; charset=us-ascii; name="patch-child" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="patch-child"diff -ur 2.4/arch/alpha/kernel/entry.S build-2.4/arch/alpha/kernel/entry.S --- 2.4/arch/alpha/kernel/entry.S Sun Sep 3 20:36:45 2000 +++ build-2.4/arch/alpha/kernel/entry.S Sun Apr 15 14:58:01 2001 @@ -242,12 +242,12 @@ subq $30,4*8,$30 stq $10,16($30) stq $9,8($30) - lda $0,CLONE_VM + lda $0,CLONE_VM|SIGCHLD stq $26,0($30) .prologue 1 mov $16,$9 /* save fn */ mov $17,$10 /* save arg */ - or $18,$0,$16 /* shuffle flags to front; add CLONE_VM. */ + or $18,$0,$16 /* shuffle flags to front; add CLONE_VM|SIGCHLD. */ bsr $26,kernel_clone bne $20,1f /* $20 is non-zero in child */ ldq $26,0($30) diff -ur 2.4/arch/arm/kernel/process.c build-2.4/arch/arm/kernel/process.c --- 2.4/arch/arm/kernel/process.c Thu Feb 22 22:28:51 2001 +++ build-2.4/arch/arm/kernel/process.c Sun Apr 15 14:51:08 2001 @@ -368,6 +368,8 @@ { pid_t __ret; + flags |= SIGCHLD; + __asm__ __volatile__( "orr r0, %1, %2 @ kernel_thread sys_clone mov r1, #0 diff -ur 2.4/arch/cris/kernel/process.c build-2.4/arch/cris/kernel/process.c --- 2.4/arch/cris/kernel/process.c Sat Apr 7 22:01:49 2001 +++ build-2.4/arch/cris/kernel/process.c Sun Apr 15 14:51:16 2001 @@ -127,6 +127,8 @@ int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) { register long __a __asm__ ("r10"); + + flags |= SIGCHLD; __asm__ __volatile__ ("movu.w %1,r9\n\t" /* r9 contains syscall number, to sys_clone */ diff -ur 2.4/arch/i386/kernel/process.c build-2.4/arch/i386/kernel/process.c --- 2.4/arch/i386/kernel/process.c Thu Feb 22 22:28:52 2001 +++ build-2.4/arch/i386/kernel/process.c Sun Apr 15 14:40:43 2001 @@ -440,6 +440,8 @@ { long retval, d0; + flags |= SIGCHLD; + __asm__ __volatile__( "movl %%esp,%%esi\n\t" "int $0x80\n\t" /* Linux/i386 system call */ diff -ur 2.4/arch/ia64/kernel/process.c build-2.4/arch/ia64/kernel/process.c --- 2.4/arch/ia64/kernel/process.c Thu Jan 4 21:50:17 2001 +++ build-2.4/arch/ia64/kernel/process.c Sun Apr 15 14:51:44 2001 @@ -500,7 +500,7 @@ struct task_struct *parent = current; int result, tid; - tid = clone(flags | CLONE_VM, 0); + tid = clone(flags | CLONE_VM | SIGCHLD, 0); if (parent != current) { result = (*fn)(arg); _exit(result); diff -ur 2.4/arch/m68k/kernel/process.c build-2.4/arch/m68k/kernel/process.c --- 2.4/arch/m68k/kernel/process.c Thu Feb 22 22:28:54 2001 +++ build-2.4/arch/m68k/kernel/process.c Sun Apr 15 14:51:58 2001 @@ -135,7 +135,7 @@ { register long retval __asm__ ("d0"); - register long clone_arg __asm__ ("d1") = flags | CLONE_VM; + register long clone_arg __asm__ ("d1") = flags | CLONE_VM | SIGCHLD; __asm__ __volatile__ ("clrl %%d2\n\t" diff -ur 2.4/arch/mips/kernel/process.c build-2.4/arch/mips/kernel/process.c --- 2.4/arch/mips/kernel/process.c Sat Apr 7 22:01:56 2001 +++ build-2.4/arch/mips/kernel/process.c Sun Apr 15 14:52:12 2001 @@ -161,6 +161,8 @@ { long retval; + flags |= SIGCHLD; + __asm__ __volatile__( ".set\tnoreorder\n\t" "move\t$6,$sp\n\t" diff -ur 2.4/arch/mips64/kernel/process.c build-2.4/arch/mips64/kernel/process.c --- 2.4/arch/mips64/kernel/process.c Thu Feb 22 22:28:55 2001 +++ build-2.4/arch/mips64/kernel/process.c Sun Apr 15 14:52:21 2001 @@ -154,6 +154,8 @@ { int retval; + flags |= SIGCHLD; + __asm__ __volatile__( "move\t$6, $sp\n\t" "move\t$4, %5\n\t" diff -ur 2.4/arch/parisc/kernel/entry.S build-2.4/arch/parisc/kernel/entry.S --- 2.4/arch/parisc/kernel/entry.S Sat Apr 7 22:01:58 2001 +++ build-2.4/arch/parisc/kernel/entry.S Sun Apr 15 14:56:58 2001 @@ -497,7 +497,7 @@ #endif STREG %r26, PT_GR26(%r1) /* Store function & argument for child */ STREG %r25, PT_GR25(%r1) - ldo CLONE_VM(%r0), %r26 /* Force CLONE_VM since only init_mm */ + ldo SIGCHLD|CLONE_VM(%r0), %r26 /* Force CLONE_VM since only init_mm */ or %r26, %r24, %r26 /* will have kernel mappings. */ copy %r0, %r25 bl do_fork, %r2 diff -ur 2.4/arch/ppc/kernel/misc.S build-2.4/arch/ppc/kernel/misc.S --- 2.4/arch/ppc/kernel/misc.S Sat Apr 7 22:01:59 2001 +++ build-2.4/arch/ppc/kernel/misc.S Sun Apr 15 14:56:17 2001 @@ -1080,7 +1080,7 @@ */ _GLOBAL(kernel_thread) mr r6,r3 /* function */ - ori r3,r5,CLONE_VM /* flags */ + ori r3,r5,CLONE_VM|SIGCHLD /* flags */ li r0,__NR_clone sc cmpi 0,r3,0 /* parent or child? */ diff -ur 2.4/arch/s390/kernel/process.c build-2.4/arch/s390/kernel/process.c --- 2.4/arch/s390/kernel/process.c Thu Feb 22 22:28:57 2001 +++ build-2.4/arch/s390/kernel/process.c Sun Apr 15 14:52:58 2001 @@ -242,7 +242,7 @@ int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) { - int clone_arg = flags | CLONE_VM; + int clone_arg = flags | CLONE_VM | SIGCHLD; int retval; __asm__ __volatile__( diff -ur 2.4/arch/s390x/kernel/process.c build-2.4/arch/s390x/kernel/process.c --- 2.4/arch/s390x/kernel/process.c Thu Feb 22 22:28:57 2001 +++ build-2.4/arch/s390x/kernel/process.c Sun Apr 15 14:53:06 2001 @@ -242,7 +242,7 @@ int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) { - int clone_arg = flags | CLONE_VM; + int clone_arg = flags | CLONE_VM | SIGCHLD; int retval; __asm__ __volatile__( diff -ur 2.4/arch/sh/kernel/process.c build-2.4/arch/sh/kernel/process.c --- 2.4/arch/sh/kernel/process.c Thu Feb 22 22:28:57 2001 +++ build-2.4/arch/sh/kernel/process.c Sun Apr 15 14:53:16 2001 @@ -148,7 +148,7 @@ { /* Don't use this in BL=1(cli). Or else, CPU resets! */ register unsigned long __sc0 __asm__ ("r0"); register unsigned long __sc3 __asm__ ("r3") = __NR_clone; - register unsigned long __sc4 __asm__ ("r4") = (long) flags | CLONE_VM; + register unsigned long __sc4 __asm__ ("r4") = (long) flags | CLONE_VM | SIGCHLD; register unsigned long __sc5 __asm__ ("r5") = 0; register unsigned long __sc8 __asm__ ("r8") = (long) arg; register unsigned long __sc9 __asm__ ("r9") = (long) fn; diff -ur 2.4/arch/sparc/kernel/process.c build-2.4/arch/sparc/kernel/process.c --- 2.4/arch/sparc/kernel/process.c Thu Feb 22 22:28:57 2001 +++ build-2.4/arch/sparc/kernel/process.c Sun Apr 15 14:53:39 2001 @@ -678,6 +678,8 @@ { long retval; + flags |= SIGCHLD; + __asm__ __volatile("mov %4, %%g2\n\t" /* Set aside fn ptr... */ "mov %5, %%g3\n\t" /* and arg. */ "mov %1, %%g1\n\t" diff -ur 2.4/arch/sparc64/kernel/process.c build-2.4/arch/sparc64/kernel/process.c --- 2.4/arch/sparc64/kernel/process.c Sat Mar 31 21:47:37 2001 +++ build-2.4/arch/sparc64/kernel/process.c Sun Apr 15 14:53:49 2001 @@ -647,6 +647,8 @@ { long retval; + flags |= SIGCHLD; + /* If the parent runs before fn(arg) is called by the child, * the input registers of this function can be clobbered. * So we stash 'fn' and 'arg' into global registers which
--------------DE1890DE7E5BD7D6D7A75795--
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