==================================================================
BUG: KMSAN: uninit-value in update_stack_state+0x673/0xa40 arch/x86/kernel/unwind_frame.c:222
CPU: 1 PID: 3575 Comm: syzkaller287285 Not tainted 4.16.0+ #82
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
 update_stack_state+0x673/0xa40 arch/x86/kernel/unwind_frame.c:222
 unwind_next_frame+0x618/0xe50 arch/x86/kernel/unwind_frame.c:329
 __unwind_start+0x508/0x630 arch/x86/kernel/unwind_frame.c:414
 unwind_start arch/x86/include/asm/unwind.h:54 [inline]
 __save_stack_trace+0x3e1/0xa80 arch/x86/kernel/stacktrace.c:43
 save_stack_trace_tsk+0x258/0x2f0 arch/x86/kernel/stacktrace.c:76
 proc_pid_stack+0x26a/0x470 fs/proc/base.c:446
 proc_single_show+0x1af/0x300 fs/proc/base.c:747
 seq_read+0xc7d/0x2260 fs/seq_file.c:237
 do_loop_readv_writev fs/read_write.c:673 [inline]
 do_iter_read+0x880/0xd70 fs/read_write.c:897
 vfs_readv fs/read_write.c:959 [inline]
 do_readv+0x295/0x5f0 fs/read_write.c:992
 SYSC_readv+0x9b/0xb0 fs/read_write.c:1079
 SyS_readv+0x56/0x80 fs/read_write.c:1076
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x4400a9
RSP: 002b:00007fff9495d6a8 EFLAGS: 00000213 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400a9
RDX: 0000000000000001 RSI: 000000002066dff0 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000010 R09: 65732f636f72702f
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401930
R13: 00000000004019c0 R14: 0000000000000000 R15: 0000000000000000

Local variable description: ----key.i.i@from_kgid
Variable was created at:
 from_kgid+0x52/0x410 kernel/user_namespace.c:480
 kgid_has_mapping include/linux/uidgid.h:138 [inline]
 privileged_wrt_inode_uidgid kernel/capability.c:471 [inline]
 capable_wrt_inode_uidgid+0x25f/0x390 kernel/capability.c:487
==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 3575 Comm: syzkaller287285 Tainted: G    B            4.16.0+ #82
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 panic+0x39d/0x940 kernel/panic.c:183
 kmsan_report+0x238/0x240 mm/kmsan/kmsan.c:1083
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
 update_stack_state+0x673/0xa40 arch/x86/kernel/unwind_frame.c:222
 unwind_next_frame+0x618/0xe50 arch/x86/kernel/unwind_frame.c:329
 __unwind_start+0x508/0x630 arch/x86/kernel/unwind_frame.c:414
 unwind_start arch/x86/include/asm/unwind.h:54 [inline]
 __save_stack_trace+0x3e1/0xa80 arch/x86/kernel/stacktrace.c:43
 save_stack_trace_tsk+0x258/0x2f0 arch/x86/kernel/stacktrace.c:76
 proc_pid_stack+0x26a/0x470 fs/proc/base.c:446
 proc_single_show+0x1af/0x300 fs/proc/base.c:747
 seq_read+0xc7d/0x2260 fs/seq_file.c:237
 do_loop_readv_writev fs/read_write.c:673 [inline]
 do_iter_read+0x880/0xd70 fs/read_write.c:897
 vfs_readv fs/read_write.c:959 [inline]
 do_readv+0x295/0x5f0 fs/read_write.c:992
 SYSC_readv+0x9b/0xb0 fs/read_write.c:1079
 SyS_readv+0x56/0x80 fs/read_write.c:1076
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x4400a9
RSP: 002b:00007fff9495d6a8 EFLAGS: 00000213 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004400a9
RDX: 0000000000000001 RSI: 000000002066dff0 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000010 R09: 65732f636f72702f
R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401930
R13: 00000000004019c0 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..