[syzbot] [fs?] BUG: unable to handle kernel NULL pointer dereference in filemap_read_folio (4)

[syzbot <syzbot+09b7d050e4806540153d@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    3022e9d00ebe Merge tag 'sched_ext-for-6.12-rc7-fixes' of g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=119f8ce8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=327b6119dd928cbc
dashboard link: https://syzkaller.appspot.com/bug?extid=09b7d050e4806540153d
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1656a4c0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=159f8ce8580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-3022e9d0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6539389f3983/vmlinux-3022e9d0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9ee2dbf68ed6/bzImage-3022e9d0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+09b7d050e4806540153d@syzkaller.appspotmail.com

BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 32263067 P4D 32263067 PUD 32264067 PMD 0 
Oops: Oops: 0010 [#1] PREEMPT SMP KASAN NOPTI
CPU: 3 UID: 0 PID: 5935 Comm: syz-executor262 Not tainted 6.12.0-rc7-syzkaller-00012-g3022e9d00ebe #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900036a79c8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81c26c1f
RDX: ffff8880289da440 RSI: ffffea0000e995c0 RDI: ffff888029a421c0
RBP: ffffea0000e995c0 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff961d8908 R12: 1ffff920006d4f3a
R13: ffff888029a421c0 R14: 0000000000000000 R15: dffffc0000000000
FS:  000055557e035380(0000) GS:ffff88806a900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000031818000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 filemap_read_folio+0xc6/0x2a0 mm/filemap.c:2367
 do_read_cache_folio+0x263/0x5c0 mm/filemap.c:3825
 freader_get_folio+0x337/0x8e0 lib/buildid.c:77
 freader_fetch+0xc2/0x5f0 lib/buildid.c:120
 __build_id_parse.isra.0+0xed/0x7a0 lib/buildid.c:305
 do_procmap_query+0xd62/0x1030 fs/proc/task_mmu.c:534
 procfs_procmap_ioctl+0x7d/0xb0 fs/proc/task_mmu.c:613
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18f/0x220 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f4c4436e9
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffde11efd68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffde11efd70 RCX: 00007f5f4c4436e9
RDX: 0000000020000180 RSI: 00000000c0686611 RDI: 0000000000000004
RBP: 00007f5f4c4b6610 R08: 0000000000000000 R09: 65732f636f72702f
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffde11effa8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc900036a79c8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81c26c1f
RDX: ffff8880289da440 RSI: ffffea0000e995c0 RDI: ffff888029a421c0
RBP: ffffea0000e995c0 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff961d8908 R12: 1ffff920006d4f3a
R13: ffff888029a421c0 R14: 0000000000000000 R15: dffffc0000000000
FS:  000055557e035380(0000) GS:ffff88806a900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000031818000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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