Fix race conditions in pldd that may leave the process stopped after detaching

Fixes bug 15804
This commit is contained in:
Andreas Schwab 2013-07-30 11:58:45 +02:00
parent d4ec6ae19e
commit b04acb2651
3 changed files with 32 additions and 1 deletions

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@ -1,3 +1,9 @@
2014-02-24 Andreas Schwab <schwab@suse.de>
[BZ #15804]
* elf/pldd.c (wait_for_ptrace_stop): New function.
(main): Call it after attaching.
2014-02-22 Roland McGrath <roland@hack.frob.com>
* Makerules ($(common-objpfx)Versions.v.i): No longer depend

2
NEWS
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@ -9,7 +9,7 @@ Version 2.20
* The following bugs are resolved with this release:
15894, 16447, 16545, 16574, 16600, 16609, 16610, 16611.
15804, 15894, 16447, 16545, 16574, 16600, 16609, 16610, 16611.
* The am33 port, which had not worked for several years, has been removed
from ports.

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@ -34,6 +34,7 @@
#include <unistd.h>
#include <sys/ptrace.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <ldsodefs.h>
#include <version.h>
@ -82,6 +83,7 @@ static char *exe;
/* Local functions. */
static int get_process_info (int dfd, long int pid);
static void wait_for_ptrace_stop (long int pid);
int
@ -170,6 +172,8 @@ main (int argc, char *argv[])
tid);
}
wait_for_ptrace_stop (tid);
struct thread_list *newp = alloca (sizeof (*newp));
newp->tid = tid;
newp->next = thread_list;
@ -194,6 +198,27 @@ main (int argc, char *argv[])
}
/* Wait for PID to enter ptrace-stop state after being attached. */
static void
wait_for_ptrace_stop (long int pid)
{
int status;
/* While waiting for SIGSTOP being delivered to the tracee we have to
reinject any other pending signal. Ignore all other errors. */
while (waitpid (pid, &status, __WALL) == pid && WIFSTOPPED (status))
{
/* The STOP signal should not be delivered to the tracee. */
if (WSTOPSIG (status) == SIGSTOP)
return;
if (ptrace (PTRACE_CONT, pid, NULL,
(void *) (uintptr_t) WSTOPSIG (status)))
/* The only possible error is that the process died. */
return;
}
}
/* Handle program arguments. */
static error_t
parse_opt (int key, char *arg, struct argp_state *state)