[PATCH] UML - signal bug fix

From: Jeff Dike
Date: Thu Nov 11 2004 - 12:52:59 EST


This patch fixes a bug introduced in the last batch of signal fixes. The
system call return value should only be reset if called diectly from a system
call, i.e. sigsuspend. The fixes added earlier caused any interrupted non-zero
system call return to be reset, confusing fork and vfork, among others.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>

Index: 2.6.9/arch/um/kernel/signal_kern.c
===================================================================
--- 2.6.9.orig/arch/um/kernel/signal_kern.c 2004-11-08 19:14:45.000000000 -0500
+++ 2.6.9/arch/um/kernel/signal_kern.c 2004-11-11 11:44:05.000000000 -0500
@@ -40,19 +40,19 @@
*/
static void handle_signal(struct pt_regs *regs, unsigned long signr,
struct k_sigaction *ka, siginfo_t *info,
- sigset_t *oldset)
+ sigset_t *oldset, int error)
{
__sighandler_t handler;
void (*restorer)(void);
unsigned long sp;
sigset_t save;
- int error, err, ret;
+ int err, ret;

- error = PT_REGS_SYSCALL_RET(&current->thread.regs);
+ err = PT_REGS_SYSCALL_RET(&current->thread.regs);
ret = 0;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
- switch(error){
+ switch(err){
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
ret = -EINTR;
@@ -99,7 +99,8 @@
if((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
sp = current->sas_ss_sp + current->sas_ss_size;

- if(error != 0) PT_REGS_SET_SYSCALL_RETURN(regs, ret);
+ if(error != 0)
+ PT_REGS_SET_SYSCALL_RETURN(regs, ret);

if (ka->sa.sa_flags & SA_RESTORER) restorer = ka->sa.sa_restorer;
else restorer = NULL;
@@ -114,7 +115,7 @@
force_sigsegv(signr, current);
}

-static int kern_do_signal(struct pt_regs *regs, sigset_t *oldset)
+static int kern_do_signal(struct pt_regs *regs, sigset_t *oldset, int error)
{
struct k_sigaction ka_copy;
siginfo_t info;
@@ -126,7 +127,7 @@
sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL);
if(sig > 0){
/* Whee! Actually deliver the signal. */
- handle_signal(regs, sig, &ka_copy, &info, oldset);
+ handle_signal(regs, sig, &ka_copy, &info, oldset, error);
return(1);
}

@@ -160,7 +161,7 @@

int do_signal(int error)
{
- return(kern_do_signal(&current->thread.regs, NULL));
+ return(kern_do_signal(&current->thread.regs, NULL, error));
}

/*
@@ -181,7 +182,7 @@
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
- if(kern_do_signal(&current->thread.regs, &saveset))
+ if(kern_do_signal(&current->thread.regs, &saveset, -EINTR))
return(-EINTR);
}
}
@@ -208,7 +209,7 @@
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
- if (kern_do_signal(&current->thread.regs, &saveset))
+ if (kern_do_signal(&current->thread.regs, &saveset, -EINTR))
return(-EINTR);
}
}

-
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