summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorAnju T Sudhakar <anju@linux.vnet.ibm.com>2017-10-13 11:29:41 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2017-10-13 20:08:40 +1100
commit0d8ba16278ec30a262d931875018abee332f926f (patch)
tree9715a43f1c0a731372660f2db62b722a8befb7c2
parentcd4f2b30e5ef7d4bde61eb515372d96e8aec1690 (diff)
downloadlinux-sh-0d8ba16278ec30a262d931875018abee332f926f.tar.gz
powerpc/perf: Fix IMC initialization crash
Panic observed with latest firmware, and upstream kernel: NIP init_imc_pmu+0x8c/0xcf0 LR init_imc_pmu+0x2f8/0xcf0 Call Trace: init_imc_pmu+0x2c8/0xcf0 (unreliable) opal_imc_counters_probe+0x300/0x400 platform_drv_probe+0x64/0x110 driver_probe_device+0x3d8/0x580 __driver_attach+0x14c/0x1a0 bus_for_each_dev+0x8c/0xf0 driver_attach+0x34/0x50 bus_add_driver+0x298/0x350 driver_register+0x9c/0x180 __platform_driver_register+0x5c/0x70 opal_imc_driver_init+0x2c/0x40 do_one_initcall+0x64/0x1d0 kernel_init_freeable+0x280/0x374 kernel_init+0x24/0x160 ret_from_kernel_thread+0x5c/0x74 While registering nest imc at init, cpu-hotplug callback nest_pmu_cpumask_init() makes an OPAL call to stop the engine. And if the OPAL call fails, imc_common_cpuhp_mem_free() is invoked to cleanup memory and cpuhotplug setup. But when cleaning up the attribute group, we are dereferencing the attribute element array without checking whether the backing element is not NULL. This causes the kernel panic. Add a check for the backing element prior to dereferencing the attribute element, to handle the failing case gracefully. Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com> Reported-by: Pridhiviraj Paidipeddi <ppaidipe@linux.vnet.ibm.com> [mpe: Trim change log] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/perf/imc-pmu.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index 39a0203fd8a5..88126245881b 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -1176,7 +1176,8 @@ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
}
/* Only free the attr_groups which are dynamically allocated */
- kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]->attrs);
+ if (pmu_ptr->attr_groups[IMC_EVENT_ATTR])
+ kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]->attrs);
kfree(pmu_ptr->attr_groups[IMC_EVENT_ATTR]);
kfree(pmu_ptr);
return;