diff options
| -rw-r--r-- | arch/s390/kernel/perf_cpum_sf.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c index 874762a51c54..7490c52b2715 100644 --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -185,7 +185,7 @@ static int realloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb, gfp_t gfp_flags) { int i, rc; - unsigned long *new, *tail; + unsigned long *new, *tail, *tail_prev = NULL; if (!sfb->sdbt || !sfb->tail) return -EINVAL; @@ -224,6 +224,7 @@ static int realloc_sampling_buffer(struct sf_buffer *sfb, sfb->num_sdbt++; /* Link current page to tail of chain */ *tail = (unsigned long)(void *) new + 1; + tail_prev = tail; tail = new; } @@ -233,10 +234,22 @@ static int realloc_sampling_buffer(struct sf_buffer *sfb, * issue, a new realloc call (if required) might succeed. */ rc = alloc_sample_data_block(tail, gfp_flags); - if (rc) + if (rc) { + /* Undo last SDBT. An SDBT with no SDB at its first + * entry but with an SDBT entry instead can not be + * handled by the interrupt handler code. + * Avoid this situation. + */ + if (tail_prev) { + sfb->num_sdbt--; + free_page((unsigned long) new); + tail = tail_prev; + } break; + } sfb->num_sdb++; tail++; + tail_prev = new = NULL; /* Allocated at least one SBD */ } /* Link sampling buffer to its origin */ |