Hi, sir:
I use mtcp to checkpoint/restart the testmtcp,
But some times the mtcp_restart will core dump.
I found that the function sigaction() caused the issue:
/* If ACT is not NULL, change the action for SIG to *ACT.
If OACT is not NULL, put the old action for SIG in *OACT. */
int __attribute__ ((visibility ("hidden")))
mtcp_sigaction (int sig, const struct sigaction *act,
struct sigaction *oact)
{
int result;
struct kernel_sigaction kact, koact;
/* if sig != SIGCANCEL and sig != SIGSETXID, use glibc version */
if (sig != 32 && sig != 33) {
if (dmtcp_exists) /* then _real_sigaction defined by DMTCP; avoid wrapper */
return mtcp_sigaction_entry(sig, act, oact);
else /* this will go directly to glibc */
return sigaction(sig, act, oact); // The program will core dump here.
}
/* else make direct call to kernel;
* glibc would hide signal 32 (SIGCANCEL/SIGTIMER) and 33 (SIGSETXID) */
if (act)
{
kact.k_sa_handler = act->sa_handler;
mtcp_sys_memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
kact.sa_flags = act->sa_flags | SA_RESTORER;
/* If MTCP called this, then it must be for MTCP restart. Hence, MTCP
* had previously saved the restorer function. act->sa_restorer is valid.
*/
kact.sa_restorer = act->sa_restorer;
}
/* XXX The size argument hopefully will have to be changed to the
real size of the user-level sigset_t. */
result = mtcp_sys_rt_sigaction( sig, act ? &kact : NULL,
oact ? &koact : NULL, _NSIG / 8);
if (oact && result >= 0)
{
oact->sa_handler = koact.k_sa_handler;
mtcp_sys_memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
oact->sa_flags = koact.sa_flags;
/* During checkpoint, MTCP calls this to save action for signals 32, 33
* If glibc uses signals 32/33, it'll have already installed the restorer
*/
oact->sa_restorer = koact.sa_restorer;
}
errno = mtcp_sys_errno; /* needed for mtcp_sys_rt_sigaction */
return result;
}
Best regards!
---------------------------------------------
guosheng_gao 高国胜
Realsil Microelectronics Inc.
Tel: +86-512-6258-8966 ext.6617
E-Mail: [email protected]<mailto:[email protected]>
---------------------------------------------
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