==================================================================
BUG: KMSAN: uninit-value in pointer+0x11e5/0x1410 lib/vsprintf.c:1862
CPU: 0 PID: 8474 Comm: syz-executor2 Not tainted 4.17.0-rc3+ #88
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+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 pointer+0x11e5/0x1410 lib/vsprintf.c:1862
 vsnprintf+0xa2d/0x33c0 lib/vsprintf.c:2296
 seq_vprintf fs/seq_file.c:403 [inline]
 seq_printf+0x29f/0x420 fs/seq_file.c:418
 proc_pid_stack+0x326/0x470 fs/proc/base.c:449
 proc_single_show+0x1af/0x300 fs/proc/base.c:747
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
 seq_read+0xc7d/0x2260 fs/seq_file.c:240
 do_loop_readv_writev fs/read_write.c:700 [inline]
 do_iter_read+0x880/0xd70 fs/read_write.c:924
 vfs_readv fs/read_write.c:986 [inline]
 do_preadv+0x3a1/0x580 fs/read_write.c:1070
 __do_sys_preadv fs/read_write.c:1120 [inline]
 __se_sys_preadv fs/read_write.c:1115 [inline]
 __x64_sys_preadv+0x120/0x170 fs/read_write.c:1115
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455979
RSP: 002b:00007f4b7acddc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007f4b7acde6d4 RCX: 0000000000455979
RDX: 00000000000000fe RSI: 00000000200023c0 RDI: 0000000000000015
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004bd R14: 00000000006fb258 R15: 0000000000000000

CPU: 1 PID: 8476 Comm: syz-executor0 Not tainted 4.17.0-rc3+ #88
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
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 __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
Call Trace:
 save_stack_trace_tsk+0x258/0x2f0 arch/x86/kernel/stacktrace.c:82
 proc_pid_stack+0x26a/0x470 fs/proc/base.c:446
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 proc_single_show+0x1af/0x300 fs/proc/base.c:747
 seq_read+0xc7d/0x2260 fs/seq_file.c:240
 fail_dump lib/fault-inject.c:51 [inline]
 should_fail+0x87b/0xab0 lib/fault-inject.c:149
 do_loop_readv_writev fs/read_write.c:700 [inline]
 do_iter_read+0x880/0xd70 fs/read_write.c:924
 vfs_readv fs/read_write.c:986 [inline]
 do_preadv+0x3a1/0x580 fs/read_write.c:1070
 __should_failslab+0x278/0x2a0 mm/failslab.c:32
 __do_sys_preadv fs/read_write.c:1120 [inline]
 __se_sys_preadv fs/read_write.c:1115 [inline]
 __x64_sys_preadv+0x120/0x170 fs/read_write.c:1115
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 should_failslab+0x29/0x70 mm/slab_common.c:1522
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
 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
 slab_pre_alloc_hook mm/slab.h:423 [inline]
 slab_alloc_node mm/slub.c:2679 [inline]
 slab_alloc mm/slub.c:2761 [inline]
 __kmalloc+0xc5/0x350 mm/slub.c:3812
 __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
 kmalloc include/linux/slab.h:517 [inline]
 ext4_getfsmap_fill fs/ext4/fsmap.c:294 [inline]
 ext4_getfsmap_find_fixed_metadata+0x1661/0x2c70 fs/ext4/fsmap.c:442
 proc_single_show+0x1af/0x300 fs/proc/base.c:747
 seq_read+0xc7d/0x2260 fs/seq_file.c:240
 ext4_getfsmap_datadev+0x5d4/0x18b0 fs/ext4/fsmap.c:505
 do_loop_readv_writev fs/read_write.c:700 [inline]
 do_iter_read+0x880/0xd70 fs/read_write.c:924
 vfs_readv fs/read_write.c:986 [inline]
 do_preadv+0x3a1/0x580 fs/read_write.c:1070
 __do_sys_preadv fs/read_write.c:1120 [inline]
 __se_sys_preadv fs/read_write.c:1115 [inline]
 __x64_sys_preadv+0x120/0x170 fs/read_write.c:1115
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 ext4_getfsmap+0x12d3/0x13b0 fs/ext4/fsmap.c:705
 entry_SYSCALL_64_after_hwframe+0x44/0xa9