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BUG: KMSAN: uninit-value in update_stack_state+0x673/0xa40 arch/x86/kernel/unwind_frame.c:222
CPU: 1 PID: 6996 Comm: syz-executor2 Not tainted 4.16.0+ #83
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_preadv+0x3a1/0x580 fs/read_write.c:1043
 SYSC_preadv+0xc6/0xe0 fs/read_write.c:1093
 SyS_preadv+0x77/0xa0 fs/read_write.c:1088
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455319
RSP: 002b:00007f99dda43c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007f99dda446d4 RCX: 0000000000455319
RDX: 0000000000000007 RSI: 0000000020000a80 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000046f R14: 00000000006f9b08 R15: 0000000000000000

Local variable description: ----c.i.i.i.i.i.i.i.i.i@gup_pgd_range
Variable was created at:
 gup_pgd_range+0x110/0x2e80 mm/gup.c:1702
 get_user_pages_fast+0x26e/0x760 mm/gup.c:1815
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