From: Vitaly Kuznetsov <[mailto:vkuznets@xxxxxxxxxx]> SynIC has to be switched off when we unload the module, otherwise registered memory pages can get corrupted after (as Hyper-V host still writes there) and we see the following crashes for random processes: [ 89.116774] BUG: Bad page map in process sh pte:4989c716 pmd:36f81067 [ 89.159454] addr:0000000000437000 vm_flags:00000875 anon_vma: (null) mapping:ffff88007bba55a0 index:37 [ 89.226146] vma->vm_ops->fault: filemap_fault+0x0/0x410 [ 89.257776] vma->vm_file->f_op->mmap: generic_file_mmap+0x0/0x60 [ 89.297570] CPU: 0 PID: 215 Comm: sh Tainted: G B 3.19.0-rc5_bug923184+ #488 [ 89.353738] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012 [ 89.409138] 0000000000000000 000000004e083d7b ffff880036e9fa18 ffffffff81a68d31 [ 89.468724] 0000000000000000 0000000000437000 ffff880036e9fa68 ffffffff811a1e3a [ 89.519233] 000000004989c716 0000000000000037 ffffea0001edc340 0000000000437000 [ 89.575751] Call Trace: [ 89.591060] [<ffffffff81a68d31>] dump_stack+0x45/0x57 [ 89.625164] [<ffffffff811a1e3a>] print_bad_pte+0x1aa/0x250 [ 89.667234] [<ffffffff811a2c95>] vm_normal_page+0x55/0xa0 [ 89.703818] [<ffffffff811a3105>] unmap_page_range+0x425/0x8a0 [ 89.737982] [<ffffffff811a3601>] unmap_single_vma+0x81/0xf0 [ 89.780385] [<ffffffff81184320>] ? lru_deactivate_fn+0x190/0x190 [ 89.820130] [<ffffffff811a4131>] unmap_vmas+0x51/0xa0 [ 89.860168] [<ffffffff811ad12c>] exit_mmap+0xac/0x1a0 [ 89.890588] [<ffffffff810763c3>] mmput+0x63/0x100 [ 89.919205] [<ffffffff811eba48>] flush_old_exec+0x3f8/0x8b0 [ 89.962135] [<ffffffff8123b5bb>] load_elf_binary+0x32b/0x1260 [ 89.998581] [<ffffffff811a14f2>] ? get_user_pages+0x52/0x60 hv_synic_cleanup() function exists but noone calls it now. Do the following: - call hv_synic_cleanup() on each cpu from vmbus_exit(); - write global disable bit through MSR; - use hv_synic_free_cpu() to avoid memory leask and code duplication. Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> --- drivers/hv/hv.c | 9 +++++++-- drivers/hv/vmbus_drv.c | 4 ++++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index 50e51a5..39531dc 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -477,6 +477,7 @@ void hv_synic_cleanup(void *arg) union hv_synic_sint shared_sint; union hv_synic_simp simp; union hv_synic_siefp siefp; + union hv_synic_scontrol sctrl; int cpu = smp_processor_id(); if (!hv_context.synic_initialized) @@ -502,6 +503,10 @@ void hv_synic_cleanup(void *arg) wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64); - free_page((unsigned long)hv_context.synic_message_page[cpu]); - free_page((unsigned long)hv_context.synic_event_page[cpu]); + /* Disable the global synic bit */ + rdmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64); + sctrl.enable = 0; + wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64); + + hv_synic_free_cpu(cpu); } diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index f824c08..28d19e8 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1099,11 +1099,15 @@ cleanup: static void __exit vmbus_exit(void) { + int cpu; + vmbus_connection.conn_state = DISCONNECTED; hv_remove_vmbus_irq(); vmbus_free_channels(); bus_unregister(&hv_bus); hv_cleanup(); + for_each_online_cpu(cpu) + smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1); acpi_bus_unregister_driver(&vmbus_acpi_driver); hv_cpu_hotplug_quirk(false); vmbus_disconnect(); -- 1.7.4.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
