From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> commit 376565b9717c30cd58ad33860fa42697615fa2e4 upstream. KMSAN complains that the vmci_use_ppn64() == false path in vmci_dbell_register_notification_bitmap() left upper 32bits of bitmap_set_msg.bitmap_ppn64 member uninitialized. ===================================================== BUG: KMSAN: uninit-value in kmsan_check_memory+0xd/0x10 CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.11.0-rc7+ #4 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020 Call Trace: dump_stack+0x21c/0x280 kmsan_report+0xfb/0x1e0 kmsan_internal_check_memory+0x484/0x520 kmsan_check_memory+0xd/0x10 iowrite8_rep+0x86/0x380 vmci_send_datagram+0x150/0x280 vmci_dbell_register_notification_bitmap+0x133/0x1e0 vmci_guest_probe_device+0xcab/0x1e70 pci_device_probe+0xab3/0xe70 really_probe+0xd16/0x24d0 driver_probe_device+0x29d/0x3a0 device_driver_attach+0x25a/0x490 __driver_attach+0x78c/0x840 bus_for_each_dev+0x210/0x340 driver_attach+0x89/0xb0 bus_add_driver+0x677/0xc40 driver_register+0x485/0x8e0 __pci_register_driver+0x1ff/0x350 vmci_guest_init+0x3e/0x41 vmci_drv_init+0x1d6/0x43f do_one_initcall+0x39c/0x9a0 do_initcall_level+0x1d7/0x259 do_initcalls+0x127/0x1cb do_basic_setup+0x33/0x36 kernel_init_freeable+0x29a/0x3ed kernel_init+0x1f/0x840 ret_from_fork+0x1f/0x30 Local variable ----bitmap_set_msg@vmci_dbell_register_notification_bitmap created at: vmci_dbell_register_notification_bitmap+0x50/0x1e0 vmci_dbell_register_notification_bitmap+0x50/0x1e0 Bytes 28-31 of 32 are uninitialized Memory access of size 32 starts at ffff88810098f570 ===================================================== Fixes: 83e2ec765be03e8a ("VMCI: doorbell implementation.") Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210402121742.3917-1-penguin-kernel@xxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/misc/vmw_vmci/vmci_doorbell.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/misc/vmw_vmci/vmci_doorbell.c +++ b/drivers/misc/vmw_vmci/vmci_doorbell.c @@ -334,7 +334,7 @@ int vmci_dbell_host_context_notify(u32 s bool vmci_dbell_register_notification_bitmap(u32 bitmap_ppn) { int result; - struct vmci_notify_bm_set_msg bitmap_set_msg; + struct vmci_notify_bm_set_msg bitmap_set_msg = { }; bitmap_set_msg.hdr.dst = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID, VMCI_SET_NOTIFY_BITMAP);