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um: Make errors to stop ptraced child fatal during startup

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For the detection code to check whether SYSEMU_SINGLESTEP works
correctly we needed some error cases while stopping to be non-fatal.
However, at this point stop_ptraced_child must always succeed, and we
can therefore simplify it slightly to exit immediately on error.

Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Benjamin Berg 2023-11-10 12:03:40 +01:00 • committed by Richard Weinberger
parent 5713533794
commit 9e16fb933f
1 changed files with 12 additions and 29 deletions
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41
arch/um/os-Linux/start_up.c
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@ -112,35 +112,20 @@ static int start_ptraced_child(void)
return pid;
}
/* When testing for SYSEMU support, if it is one of the broken versions, we
* must just avoid using sysemu, not panic, but only if SYSEMU features are
* broken.
* So only for SYSEMU features we test mustpanic, while normal host features
* must work anyway!
*/
static int stop_ptraced_child(int pid, int exitcode, int mustexit)
static void stop_ptraced_child(int pid, int exitcode)
{
int status, n, ret = 0;
int status, n;
if (ptrace(PTRACE_CONT, pid, 0, 0) < 0)
fatal_perror("stop_ptraced_child : ptrace failed");
if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) {
perror("stop_ptraced_child : ptrace failed");
return -1;
}
CATCH_EINTR(n = waitpid(pid, &status, 0));
if (!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
int exit_with = WEXITSTATUS(status);
if (exit_with == 2)
non_fatal("check_ptrace : child exited with status 2. "
"\nDisabling SYSEMU support.\n");
non_fatal("check_ptrace : child exited with exitcode %d, while "
"expecting %d; status 0x%x\n", exit_with,
exitcode, status);
if (mustexit)
exit(1);
ret = -1;
fatal("stop_ptraced_child : child exited with exitcode %d, "
"while expecting %d; status 0x%x\n", exit_with,
exitcode, status);
}
return ret;
}
static void __init check_sysemu(void)
@ -185,16 +170,14 @@ static void __init check_sysemu(void)
goto fail;
}
}
if (stop_ptraced_child(pid, 0, 0) < 0)
goto fail_stopped;
stop_ptraced_child(pid, 0);
os_info("OK\n");
return;
fail:
stop_ptraced_child(pid, 1, 0);
fail_stopped:
stop_ptraced_child(pid, 1);
fatal("missing\n");
}
@ -233,7 +216,7 @@ static void __init check_ptrace(void)
break;
}
}
stop_ptraced_child(pid, 0, 1);
stop_ptraced_child(pid, 0);
os_info("OK\n");
check_sysemu();
}
@ -312,7 +295,7 @@ void __init os_early_checks(void)
pid = start_ptraced_child();
if (init_pid_registers(pid))
fatal("Failed to initialize default registers");
stop_ptraced_child(pid, 1, 1);
stop_ptraced_child(pid, 1);
}
int __init parse_iomem(char *str, int *add)