KMSAN: uninit-value in search_by_key

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    c5a13b33 kmsan: clang-format core
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=173525ab900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=20f149ad694ba4be
dashboard link: https://syzkaller.appspot.com/bug?extid=d94d02749498bb7bab4b
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d94d02749498bb7bab4b@xxxxxxxxxxxxxxxxxxxxxxxxx

=====================================================
BUG: KMSAN: uninit-value in comp_keys fs/reiserfs/stree.c:83 [inline]
BUG: KMSAN: uninit-value in bin_search fs/reiserfs/stree.c:173 [inline]
BUG: KMSAN: uninit-value in search_by_key+0x2c57/0x60e0 fs/reiserfs/stree.c:743
CPU: 1 PID: 28395 Comm: syz-executor.4 Not tainted 5.9.0-rc4-syzkaller #0
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+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219
 comp_keys fs/reiserfs/stree.c:83 [inline]
 bin_search fs/reiserfs/stree.c:173 [inline]
 search_by_key+0x2c57/0x60e0 fs/reiserfs/stree.c:743
 reiserfs_read_locked_inode+0x1fc/0x3260 fs/reiserfs/inode.c:1561
 reiserfs_fill_super+0x2c00/0x6170 fs/reiserfs/super.c:2081
 mount_bdev+0x622/0x910 fs/super.c:1417
 get_super_block+0xc9/0xe0 fs/reiserfs/super.c:2606
 legacy_get_tree+0x163/0x2e0 fs/fs_context.c:592
 vfs_get_tree+0xd8/0x5d0 fs/super.c:1547
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x3d1a/0x5d40 fs/namespace.c:3192
 do_mount+0x1c6/0x220 fs/namespace.c:3205
 __do_compat_sys_mount fs/compat.c:122 [inline]
 __se_compat_sys_mount+0x7b5/0xaa0 fs/compat.c:89
 __ia32_compat_sys_mount+0x62/0x80 fs/compat.c:89
 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
 __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139
 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fea549
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f55e3f20 EFLAGS: 00000292 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 00000000f55e3f7c RCX: 0000000020000100
RDX: 0000000020000000 RSI: 0000000000000000 RDI: 00000000f55e3fbc
RBP: 00000000f55e3f7c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Local variable ----key@reiserfs_read_locked_inode created at:
 reiserfs_read_locked_inode+0xb4/0x3260 fs/reiserfs/inode.c:1544
 reiserfs_read_locked_inode+0xb4/0x3260 fs/reiserfs/inode.c:1544
=====================================================


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