loop0: detected capacity change from 0 to 512
EXT4-fs error (device loop0): ext4_map_blocks:780: inode #2: block 3: comm syz.0.0: lblock 0 mapped to illegal pblock 3 (length 1)
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs warning (device loop0): dx_probe:791: inode #2: lblock 0: comm syz.0.0: error -117 reading directory block
EXT4-fs (loop0): Cannot turn on journaled quota: type 1: error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
EXT4-fs warning (device loop0): dx_probe:791: inode #2: lblock 0: comm syz.0.0: error -117 reading directory block
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 0 P4D 0 
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5334 Comm: syz.0.0 Not tainted 6.16.0-rc2-syzkaller-00045-g4663747812d1 #0 PREEMPT(full) 
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:ffffc9000d247998 EFLAGS: 00010283
RAX: ffffffff81f853e4 RBX: 1ffffd4000266b68 RCX: 0000000000100000
RDX: ffffc9000df22000 RSI: ffffea0001335b40 RDI: ffff8880002f9e00
RBP: ffffc9000d247a50 R08: ffffea0001335b47 R09: 1ffffd4000266b68
R10: dffffc0000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffea0001335b48 R14: ffffea0001335b40 R15: 1ffffd4000266b69
FS:  00007f9977c796c0(0000) GS:ffff88808d251000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000003f180000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 filemap_read_folio+0x114/0x380 mm/filemap.c:2412
 do_read_cache_folio+0x350/0x590 mm/filemap.c:3894
 freader_get_folio+0x3c4/0x830 lib/buildid.c:77
 freader_fetch+0xa3/0x5d0 lib/buildid.c:120
 __build_id_parse+0x133/0x7d0 lib/buildid.c:305
 do_procmap_query fs/proc/task_mmu.c:534 [inline]
 procfs_procmap_ioctl+0x7f0/0xce0 fs/proc/task_mmu.c:613
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9976d8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9977c79038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9976fb5fa0 RCX: 00007f9976d8e929
RDX: 0000200000000180 RSI: 00000000c0686611 RDI: 0000000000000007
RBP: 00007f9976e10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f9976fb5fa0 R15: 00007ffc92c50238
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000d247998 EFLAGS: 00010283
RAX: ffffffff81f853e4 RBX: 1ffffd4000266b68 RCX: 0000000000100000
RDX: ffffc9000df22000 RSI: ffffea0001335b40 RDI: ffff8880002f9e00
RBP: ffffc9000d247a50 R08: ffffea0001335b47 R09: 1ffffd4000266b68
R10: dffffc0000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffea0001335b48 R14: ffffea0001335b40 R15: 1ffffd4000266b69
FS:  00007f9977c796c0(0000) GS:ffff88808d251000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000003f180000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400