diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2016-06-04 00:09:22 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-08-31 11:05:40 (GMT) |
| commit | a9f61ca793becabdefab03b77568d6c6f8c1bc79 (patch) | |
| tree | 422f0e2eb47880341e6ebe69a1afa918458c4dd4 | |
| parent | 069b188f43d9a44422eb35a8f95533d2c44ad315 (diff) | |
| download | linux-a9f61ca793becabdefab03b77568d6c6f8c1bc79.tar.xz | |
Drivers: hv: avoid vfree() on crash
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>
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 a1c086b..60dbd6c 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -278,7 +278,7 @@ 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; @@ -288,7 +288,8 @@ 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; } @@ -308,7 +309,8 @@ 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 718b5c7..dfa9fac 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -495,7 +495,7 @@ 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 e82f7e1..fedf629 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -874,7 +874,7 @@ err_alloc: bus_unregister(&hv_bus); err_cleanup: - hv_cleanup(); + hv_cleanup(false); return ret; } @@ -1326,7 +1326,7 @@ static void hv_kexec_handler(void) vmbus_initiate_unload(false); 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) @@ -1338,7 +1338,7 @@ 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) @@ -1398,7 +1398,7 @@ 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); |