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BUG: KMSAN: uninit-value in __call_rcu+0x4b8/0xef0 kernel/rcu/tree.c:3035
CPU: 0 PID: 17943 Comm: blkid Not tainted 4.17.0-rc5+ #1
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+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x149/0x260 mm/kmsan/kmsan.c:1084
 __msan_warning_32+0x6e/0xc0 mm/kmsan/kmsan_instr.c:685
 __call_rcu+0x4b8/0xef0 kernel/rcu/tree.c:3035
 call_rcu_sched+0x32/0x40 kernel/rcu/tree.c:3097
 __put_cred+0x102/0x180 kernel/cred.c:150
 put_cred include/linux/cred.h:266 [inline]
 do_faccessat+0xa2f/0xbc0 fs/open.c:430
 __do_sys_access fs/open.c:441 [inline]
 __se_sys_access fs/open.c:439 [inline]
 __x64_sys_access+0x9c/0xd0 fs/open.c:439
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fe7157e6267
RSP: 002b:00007ffce1fafee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe7157e6267
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fe7157ea2e6
RBP: 00007ffce1faff80 R08: 000000000000003c R09: 0000000000000000
R10: 00007ffce1fd6120 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000004 R14: 00007fe7159f1758 R15: 00007fe7157ea931

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:294 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:685
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:529
 rcu_segcblist_enqueue+0x275/0x2d0 kernel/rcu/rcu_segcblist.c:151
 __call_rcu+0x227/0xef0 kernel/rcu/tree.c:3057
 call_rcu_sched+0x32/0x40 kernel/rcu/tree.c:3097
 release_task+0x24b9/0x2530 kernel/exit.c:223
 exit_notify kernel/exit.c:736 [inline]
 do_exit+0x2e11/0x3930 kernel/exit.c:887
 do_group_exit+0x1a0/0x360 kernel/exit.c:970
 get_signal+0x1405/0x1ec0 kernel/signal.c:2482
 do_signal+0xb8/0x1d20 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:162 [inline]
 prepare_exit_to_usermode+0x271/0x3a0 arch/x86/entry/common.c:196
 syscall_return_slowpath+0xe9/0x710 arch/x86/entry/common.c:265
 do_syscall_64+0x1ad/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Local variable description: ----tlb.i@ldt_arch_exit_mmap
Variable was created at:
 ldt_arch_exit_mmap+0x46/0x160 arch/x86/kernel/ldt.c:302
 arch_exit_mmap arch/x86/include/asm/mmu_context.h:245 [inline]
 exit_mmap+0x410/0x980 mm/mmap.c:3094
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