syzbot has found a reproducer for the following issue on: HEAD commit: ce8056d1 wip: changed copy_from_user where instrumented git tree: https://github.com/google/kmsan.git master console output: https://syzkaller.appspot.com/x/log.txt?x=12a834ee900000 kernel config: https://syzkaller.appspot.com/x/.config?x=3afe005fb99591f dashboard link: https://syzkaller.appspot.com/bug?extid=a7e220df5a81d1ab400e compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133bd37a900000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=133175a6900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a7e220df5a81d1ab400e@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253 CPU: 1 PID: 8488 Comm: syz-executor009 Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423 kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253 instrument_copy_to_user include/linux/instrumented.h:91 [inline] _copy_to_user+0x18e/0x260 lib/usercopy.c:39 copy_to_user include/linux/uaccess.h:186 [inline] raw_ioctl_event_fetch drivers/usb/gadget/legacy/raw_gadget.c:567 [inline] raw_ioctl+0x4995/0x5810 drivers/usb/gadget/legacy/raw_gadget.c:1213 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl fs/ioctl.c:753 [inline] __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl+0x319/0x4d0 fs/ioctl.c:760 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:760 do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x444cf7 Code: Bad RIP value. RSP: 002b:00007fff38034848 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000444cf7 RDX: 00007fff38035870 RSI: 0000000080085502 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000019 R10: 0000000000000075 R11: 0000000000000246 R12: 00000000004029f0 R13: 0000000000402a80 R14: 0000000000000000 R15: 0000000000000000 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267 __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116 raw_event_queue_add drivers/usb/gadget/legacy/raw_gadget.c:74 [inline] raw_queue_event+0x2b3/0x5c0 drivers/usb/gadget/legacy/raw_gadget.c:225 gadget_setup+0x48c/0x530 drivers/usb/gadget/legacy/raw_gadget.c:343 dummy_timer+0x2c4d/0x71c0 drivers/usb/gadget/udc/dummy_hcd.c:1899 call_timer_fn+0x226/0x550 kernel/time/timer.c:1404 expire_timers+0x4fc/0x780 kernel/time/timer.c:1449 __run_timers+0xaf4/0xd30 kernel/time/timer.c:1773 run_timer_softirq+0x2d/0x50 kernel/time/timer.c:1786 __do_softirq+0x2ea/0x7f5 kernel/softirq.c:293 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:165 dummy_timer+0x1d82/0x71c0 drivers/usb/gadget/udc/dummy_hcd.c:1867 call_timer_fn+0x226/0x550 kernel/time/timer.c:1404 expire_timers+0x4fc/0x780 kernel/time/timer.c:1449 __run_timers+0xaf4/0xd30 kernel/time/timer.c:1773 run_timer_softirq+0x2d/0x50 kernel/time/timer.c:1786 __do_softirq+0x2ea/0x7f5 kernel/softirq.c:293 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:165 usb_control_msg+0x5df/0x820 drivers/usb/core/message.c:149 __usbnet_write_cmd drivers/net/usb/usbnet.c:2035 [inline] usbnet_write_cmd+0x3de/0x480 drivers/net/usb/usbnet.c:2073 asix_write_cmd+0x18b/0x2c0 drivers/net/usb/asix_common.c:48 ax88772_hw_reset+0x1bd/0xc30 drivers/net/usb/asix_devices.c:361 ax88772_bind+0x8f3/0x1400 drivers/net/usb/asix_devices.c:730 usbnet_probe+0x1152/0x3f90 drivers/net/usb/usbnet.c:1737 usb_probe_interface+0xece/0x1550 drivers/usb/core/driver.c:374 really_probe+0xf20/0x20b0 drivers/base/dd.c:529 driver_probe_device+0x293/0x390 drivers/base/dd.c:701 __device_attach_driver+0x63f/0x830 drivers/base/dd.c:807 bus_for_each_drv+0x2ca/0x3f0 drivers/base/bus.c:431 __device_attach+0x4e2/0x7f0 drivers/base/dd.c:873 device_initial_probe+0x4a/0x60 drivers/base/dd.c:920 bus_probe_device+0x177/0x3d0 drivers/base/bus.c:491 device_add+0x3b0e/0x40d0 drivers/base/core.c:2680 usb_set_configuration+0x380f/0x3f10 drivers/usb/core/message.c:2032 usb_generic_driver_probe+0x138/0x300 drivers/usb/core/generic.c:241 usb_probe_device+0x311/0x490 drivers/usb/core/driver.c:272 really_probe+0xf20/0x20b0 drivers/base/dd.c:529 driver_probe_device+0x293/0x390 drivers/base/dd.c:701 __device_attach_driver+0x63f/0x830 drivers/base/dd.c:807 bus_for_each_drv+0x2ca/0x3f0 drivers/base/bus.c:431 __device_attach+0x4e2/0x7f0 drivers/base/dd.c:873 device_initial_probe+0x4a/0x60 drivers/base/dd.c:920 bus_probe_device+0x177/0x3d0 drivers/base/bus.c:491 device_add+0x3b0e/0x40d0 drivers/base/core.c:2680 usb_new_device+0x1bd4/0x2a30 drivers/usb/core/hub.c:2554 hub_port_connect drivers/usb/core/hub.c:5208 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x5e7b/0x8a70 drivers/usb/core/hub.c:5576 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415 kthread+0x551/0x590 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:165 ax88772_bind+0x82e/0x1400 drivers/net/usb/asix_devices.c:720 usbnet_probe+0x1152/0x3f90 drivers/net/usb/usbnet.c:1737 usb_probe_interface+0xece/0x1550 drivers/usb/core/driver.c:374 really_probe+0xf20/0x20b0 drivers/base/dd.c:529 driver_probe_device+0x293/0x390 drivers/base/dd.c:701 __device_attach_driver+0x63f/0x830 drivers/base/dd.c:807 bus_for_each_drv+0x2ca/0x3f0 drivers/base/bus.c:431 __device_attach+0x4e2/0x7f0 drivers/base/dd.c:873 device_initial_probe+0x4a/0x60 drivers/base/dd.c:920 bus_probe_device+0x177/0x3d0 drivers/base/bus.c:491 device_add+0x3b0e/0x40d0 drivers/base/core.c:2680 usb_set_configuration+0x380f/0x3f10 drivers/usb/core/message.c:2032 usb_generic_driver_probe+0x138/0x300 drivers/usb/core/generic.c:241 usb_probe_device+0x311/0x490 drivers/usb/core/driver.c:272 really_probe+0xf20/0x20b0 drivers/base/dd.c:529 driver_probe_device+0x293/0x390 drivers/base/dd.c:701 __device_attach_driver+0x63f/0x830 drivers/base/dd.c:807 bus_for_each_drv+0x2ca/0x3f0 drivers/base/bus.c:431 __device_attach+0x4e2/0x7f0 drivers/base/dd.c:873 device_initial_probe+0x4a/0x60 drivers/base/dd.c:920 bus_probe_device+0x177/0x3d0 drivers/base/bus.c:491 device_add+0x3b0e/0x40d0 drivers/base/core.c:2680 usb_new_device+0x1bd4/0x2a30 drivers/usb/core/hub.c:2554 hub_port_connect drivers/usb/core/hub.c:5208 [inline] hub_port_connect_change drivers/usb/core/hub.c:5348 [inline] port_event drivers/usb/core/hub.c:5494 [inline] hub_event+0x5e7b/0x8a70 drivers/usb/core/hub.c:5576 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415 kthread+0x551/0x590 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Local variable ----buf.i@asix_get_phy_addr created at: asix_read_cmd drivers/net/usb/asix_common.c:312 [inline] asix_read_phy_addr drivers/net/usb/asix_common.c:295 [inline] asix_get_phy_addr+0x4d/0x290 drivers/net/usb/asix_common.c:314 asix_read_cmd drivers/net/usb/asix_common.c:312 [inline] asix_read_phy_addr drivers/net/usb/asix_common.c:295 [inline] asix_get_phy_addr+0x4d/0x290 drivers/net/usb/asix_common.c:314 Byte 10 of 16 is uninitialized Memory access of size 16 starts at ffff8881051954d0 Data copied to user address 00007fff38035870 =====================================================
