[syzbot] [isofs?] KMSAN: uninit-value in isofs_readdir

[syzbot <syzbot+812641c6c3d7586a1613@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    5c8c229261f1 Merge tag 'kthreads-fixes-2025-02-04' of git:..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13a8beb0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f20bce78db15972a
dashboard link: https://syzkaller.appspot.com/bug?extid=812641c6c3d7586a1613
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12042df8580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17ff93df980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/63aa4d99d73d/disk-5c8c2292.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/104150a76e91/vmlinux-5c8c2292.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c4622f8c58f4/bzImage-5c8c2292.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/24fb8c942e20/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+812641c6c3d7586a1613@syzkaller.appspotmail.com

loop0: detected capacity change from 1764 to 1763
=====================================================
BUG: KMSAN: uninit-value in do_isofs_readdir fs/isofs/dir.c:150 [inline]
BUG: KMSAN: uninit-value in isofs_readdir+0xa33/0x2610 fs/isofs/dir.c:262
 do_isofs_readdir fs/isofs/dir.c:150 [inline]
 isofs_readdir+0xa33/0x2610 fs/isofs/dir.c:262
 iterate_dir+0x740/0x930 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:403 [inline]
 __se_sys_getdents64+0x170/0x540 fs/readdir.c:389
 __x64_sys_getdents64+0x96/0xe0 fs/readdir.c:389
 x64_sys_call+0x3b0f/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_frozen_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4762
 alloc_pages_mpol+0x4cd/0x890 mm/mempolicy.c:2270
 alloc_frozen_pages_noprof mm/mempolicy.c:2341 [inline]
 alloc_pages_noprof+0x1b5/0x250 mm/mempolicy.c:2361
 get_free_pages_noprof+0x34/0xc0 mm/page_alloc.c:4798
 isofs_readdir+0x74/0x2610 fs/isofs/dir.c:256
 iterate_dir+0x740/0x930 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:403 [inline]
 __se_sys_getdents64+0x170/0x540 fs/readdir.c:389
 __x64_sys_getdents64+0x96/0xe0 fs/readdir.c:389
 x64_sys_call+0x3b0f/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5784 Comm: syz-executor207 Not tainted 6.14.0-rc1-syzkaller-00028-g5c8c229261f1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
=====================================================


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