==================================================================
BUG: KMSAN: uninit-value in is_kernel include/linux/kallsyms.h:41 [inline]
BUG: KMSAN: uninit-value in is_ksym_addr include/linux/kallsyms.h:49 [inline]
BUG: KMSAN: uninit-value in kallsyms_lookup+0x152/0x910 kernel/kallsyms.c:288
CPU: 0 PID: 6570 Comm: syz-executor6 Not tainted 4.16.0+ #87
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:683
 is_kernel include/linux/kallsyms.h:41 [inline]
 is_ksym_addr include/linux/kallsyms.h:49 [inline]
 kallsyms_lookup+0x152/0x910 kernel/kallsyms.c:288
 __sprint_symbol+0x147/0x5b0 kernel/kallsyms.c:361
 sprint_backtrace+0x7f/0x90 kernel/kallsyms.c:429
 symbol_string+0x19f/0x230 lib/vsprintf.c:684
 pointer+0xdb9/0x1410 lib/vsprintf.c:1870
 vsnprintf+0xa2d/0x33c0 lib/vsprintf.c:2286
 seq_vprintf fs/seq_file.c:400 [inline]
 seq_printf+0x29f/0x420 fs/seq_file.c:415
 proc_pid_stack+0x326/0x470 fs/proc/base.c:449
 proc_single_show+0x1af/0x300 fs/proc/base.c:747
 seq_read+0xc7d/0x2260 fs/seq_file.c:237
 __vfs_read+0x1a5/0x9b0 fs/read_write.c:411
 vfs_read+0x36c/0x6c0 fs/read_write.c:447
 SYSC_read+0x172/0x360 fs/read_write.c:573
 SyS_read+0x55/0x80 fs/read_write.c:566
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455979
RSP: 002b:00007fdd628abc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fdd628ac6d4 RCX: 0000000000455979
RDX: 0000000000000008 RSI: 0000000020000b00 RDI: 0000000000000017
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004d6 R14: 00000000006fb4b0 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:528
 save_stack_address arch/x86/kernel/stacktrace.c:29 [inline]
 __save_stack_trace+0x829/0xb00 arch/x86/kernel/stacktrace.c:50
 save_stack_trace_tsk+0x258/0x2f0 arch/x86/kernel/stacktrace.c:82
 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
 __vfs_read+0x1a5/0x9b0 fs/read_write.c:411
 vfs_read+0x36c/0x6c0 fs/read_write.c:447
 SYSC_read+0x172/0x360 fs/read_write.c:573
 SyS_read+0x55/0x80 fs/read_write.c:566
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:528
 update_stack_state+0x959/0xa40 arch/x86/kernel/unwind_frame.c:257
 unwind_next_frame+0x618/0xe50 arch/x86/kernel/unwind_frame.c:329
 __save_stack_trace+0x734/0xb00 arch/x86/kernel/stacktrace.c:48
 save_stack_trace_tsk+0x258/0x2f0 arch/x86/kernel/stacktrace.c:82
 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
 __vfs_read+0x1a5/0x9b0 fs/read_write.c:411
 vfs_read+0x36c/0x6c0 fs/read_write.c:447
 SYSC_read+0x172/0x360 fs/read_write.c:573
 SyS_read+0x55/0x80 fs/read_write.c:566
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Local variable description: ----c.i.i.i.i@__block_write_begin_int
Variable was created at:
 __block_write_begin_int+0xe8/0x2910 fs/buffer.c:1952
 __block_write_begin fs/buffer.c:2036 [inline]
 block_page_mkwrite+0x495/0x980 fs/buffer.c:2499
==================================================================