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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-04 23:53:53 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-04 23:53:53 +0300 |
| commit | d725c7ac8b96cbdc28266895c6f7080c55bf2f23 (patch) | |
| tree | 369755212931a08450c9d5529e629ed4c63168f7 /kernel/cpu.c | |
| parent | 93cc1228b4a60584f3dadbd84f19f365bb945acb (diff) | |
| parent | 0c96b27305faf06c068b45e07d28336c80dac286 (diff) | |
| download | linux-d725c7ac8b96cbdc28266895c6f7080c55bf2f23.tar.xz | |
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull CPU hotplug fix from Thomas Gleixner:
"A single fix to handle the removal of the first dynamic CPU hotplug
state correctly"
* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
smp/hotplug: Handle removal correctly in cpuhp_store_callbacks()
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index bfbd649ccdc8..acf5308fad51 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1253,7 +1253,17 @@ static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, struct cpuhp_step *sp; int ret = 0; - if (state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN) { + /* + * If name is NULL, then the state gets removed. + * + * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on + * the first allocation from these dynamic ranges, so the removal + * would trigger a new allocation and clear the wrong (already + * empty) state, leaving the callbacks of the to be cleared state + * dangling, which causes wreckage on the next hotplug operation. + */ + if (name && (state == CPUHP_AP_ONLINE_DYN || + state == CPUHP_BP_PREPARE_DYN)) { ret = cpuhp_reserve_state(state); if (ret < 0) return ret; |