=====================================================
BUG: KMSAN: uninit-value in cont_expand_zero fs/buffer.c:2428 [inline]
BUG: KMSAN: uninit-value in cont_write_begin+0xd84/0xdc0 fs/buffer.c:2453
 cont_expand_zero fs/buffer.c:2428 [inline]
 cont_write_begin+0xd84/0xdc0 fs/buffer.c:2453
 exfat_write_begin+0x92/0x260 fs/exfat/inode.c:398
 pagecache_write_begin+0x82/0xa0 mm/filemap.c:3631
 generic_cont_expand_simple+0x11a/0x2c0 fs/buffer.c:2355
 exfat_cont_expand fs/exfat/file.c:21 [inline]
 exfat_setattr+0x20f/0x18c0 fs/exfat/file.c:295
 notify_change+0x1f1c/0x2010 fs/attr.c:410
 do_truncate+0x238/0x2d0 fs/open.c:65
 do_sys_ftruncate+0x7d7/0xab0 fs/open.c:193
 __do_compat_sys_ftruncate fs/open.c:210 [inline]
 __se_compat_sys_ftruncate fs/open.c:208 [inline]
 __ia32_compat_sys_ftruncate+0x6c/0xa0 fs/open.c:208
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x95/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Local variable fsdata.i created at:
 cont_write_begin+0xc1/0xdc0 fs/buffer.c:2453
 exfat_write_begin+0x92/0x260 fs/exfat/inode.c:398

CPU: 1 PID: 6175 Comm: syz-executor.1 Not tainted 5.18.0-syzkaller-16263-g2d0ce79ea812 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================