This allows processes to override their early/late kill behaviour on hardware memory errors. Typically applications which are memory error aware is better of with early kill (see the error as soon as possible), all others with late kill (only see the error when the error is really impacting execution) There's a global sysctl, but this way an application can set its specific policy. We're using two bits, one to signify that the process stated its intention and that I also made the prctl future proof by enforcing the unused arguments are 0. The state is inherited to children. Note this makes us officially run out of process flags on 32bit, but the next patch can easily add another field. Manpage patch will be supplied separately.
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| @@ -1528,6 +1528,28 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, · 1527 unmodified lines | ||
| 1528 | 1528 | current->timer_slack_ns = arg2; |
| 1529 | 1529 | error = 0; |
| 1530 | 1530 | break; |
| 1531 | + case PR_MCE_KILL: | |
| 1532 | + if (arg4 | arg5) | |
| 1533 | + return -EINVAL; | |
| 1534 | + switch (arg2) { | |
| 1535 | + case 0: | |
| 1536 | + if (arg3 != 0) | |
| 1537 | + return -EINVAL; | |
| 1538 | + current->flags &= ~PF_MCE_PROCESS; | |
| 1539 | + break; | |
| 1540 | + case 1: | |
| 1541 | + current->flags |= PF_MCE_PROCESS; | |
| 1542 | + if (arg3 != 0) | |
| 1543 | + current->flags |= PF_MCE_EARLY; | |
| 1544 | + else | |
| 1545 | + current->flags &= ~PF_MCE_EARLY; | |
| 1546 | + break; | |
| 1547 | + default: | |
| 1548 | + return -EINVAL; | |
| 1549 | + } | |
| 1550 | + error = 0; | |
| 1551 | + break; | |
| 1552 | + | |
| 1531 | 1553 | default: |
| 1532 | 1554 | error = -EINVAL; |
| 1533 | 1555 | break; |