diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2016-06-03 17:09:22 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-03-26 12:13:18 +0200 |
| commit | b1a0f744f8e63fbef10dc84029e9d213e03a3a18 (patch) | |
| tree | 8b5848a34d54924539ea3a133dec644865de9d3a | |
| parent | 0a2512768f1683514ef964e2e0767458baef14de (diff) | |
Drivers: hv: avoid vfree() on crash
commit a9f61ca793becabdefab03b77568d6c6f8c1bc79 upstream.
When we crash from NMI context (e.g. after NMI injection from host when
'sysctl -w kernel.unknown_nmi_panic=1' is set) we hit
kernel BUG at mm/vmalloc.c:1530!
as vfree() is denied. While the issue could be solved with in_nmi() check
instead I opted for skipping vfree on all sorts of crashes to reduce the
amount of work which can cause consequent crashes. We don't really need to
free anything on crash.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/hv/hv.c | 8 | ||||
| -rw-r--r-- | drivers/hv/hyperv_vmbus.h | 2 | ||||
| -rw-r--r-- | drivers/hv/vmbus_drv.c | 8 |
3 files changed, 10 insertions, 8 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 57c191798699..ddbf7e7e0d98 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -274,7 +274,7 @@ cleanup: * * This routine is called normally during driver unloading or exiting. */ -void hv_cleanup(void) +void hv_cleanup(bool crash) { union hv_x64_msr_hypercall_contents hypercall_msr; @@ -284,7 +284,8 @@ void hv_cleanup(void) if (hv_context.hypercall_page) { hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); - vfree(hv_context.hypercall_page); + if (!crash) + vfree(hv_context.hypercall_page); hv_context.hypercall_page = NULL; } @@ -304,7 +305,8 @@ void hv_cleanup(void) hypercall_msr.as_uint64 = 0; wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64); - vfree(hv_context.tsc_page); + if (!crash) + vfree(hv_context.tsc_page); hv_context.tsc_page = NULL; } #endif diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index 12156db2e88e..75e383e6d03d 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -581,7 +581,7 @@ struct hv_ring_buffer_debug_info { extern int hv_init(void); -extern void hv_cleanup(void); +extern void hv_cleanup(bool crash); extern int hv_post_message(union hv_connection_id connection_id, enum hv_message_type message_type, diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 509ed9731630..802dcb409030 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -889,7 +889,7 @@ err_alloc: bus_unregister(&hv_bus); err_cleanup: - hv_cleanup(); + hv_cleanup(false); return ret; } @@ -1254,7 +1254,7 @@ static void hv_kexec_handler(void) vmbus_initiate_unload(); for_each_online_cpu(cpu) smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1); - hv_cleanup(); + hv_cleanup(false); }; static void hv_crash_handler(struct pt_regs *regs) @@ -1266,7 +1266,7 @@ static void hv_crash_handler(struct pt_regs *regs) * for kdump. */ hv_synic_cleanup(NULL); - hv_cleanup(); + hv_cleanup(true); }; static int __init hv_acpi_init(void) @@ -1330,7 +1330,7 @@ static void __exit vmbus_exit(void) &hyperv_panic_block); } bus_unregister(&hv_bus); - hv_cleanup(); + hv_cleanup(false); for_each_online_cpu(cpu) { tasklet_kill(hv_context.event_dpc[cpu]); smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1); |