diff options
| author | Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com> | 2017-10-19 21:41:33 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-10-25 12:41:13 +0200 |
| commit | 0b167f11085a34281349f395d200052b61a7e221 (patch) | |
| tree | 323931d5300107fae8ed66a354f3051b6b0b3131 /arch | |
| parent | powerpc/perf: Fix IMC initialization crash (diff) | |
| download | linux-0b167f11085a34281349f395d200052b61a7e221.tar.xz linux-0b167f11085a34281349f395d200052b61a7e221.zip | |
powerpc/perf: Fix IMC allocation routine
When setting nr_cpus=1, we observed a crash in IMC code during boot
due to a missing allocation: basically, IMC code is taking the number
of threads into account in imc_mem_init() and if we manually set
nr_cpus for a value that is not multiple of the number of threads per
core, an integer division in that function will discard the decimal
portion, leading IMC to not allocate one mem_info struct. This causes
a NULL pointer dereference later, on is_core_imc_mem_inited().
This patch just rounds that division up, fixing the bug.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Acked-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/perf/imc-pmu.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c index 88126245881b..92ae5de0bbac 100644 --- a/arch/powerpc/perf/imc-pmu.c +++ b/arch/powerpc/perf/imc-pmu.c @@ -1104,7 +1104,7 @@ static int init_nest_pmu_ref(void) static void cleanup_all_core_imc_memory(void) { - int i, nr_cores = num_present_cpus() / threads_per_core; + int i, nr_cores = DIV_ROUND_UP(num_present_cpus(), threads_per_core); struct imc_mem_info *ptr = core_imc_pmu->mem_info; int size = core_imc_pmu->counter_mem_size; @@ -1212,7 +1212,7 @@ static int imc_mem_init(struct imc_pmu *pmu_ptr, struct device_node *parent, if (!pmu_ptr->pmu.name) return -ENOMEM; - nr_cores = num_present_cpus() / threads_per_core; + nr_cores = DIV_ROUND_UP(num_present_cpus(), threads_per_core); pmu_ptr->mem_info = kcalloc(nr_cores, sizeof(struct imc_mem_info), GFP_KERNEL); |