loop2: detected capacity change from 0 to 16 erofs: (device loop2): mounted with root inode @ nid 36. erofs: (device loop2): z_erofs_extent_lookback: bogus lookback distance @ nid 36 BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 12ee48067 P4D 12ee48067 PUD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 1 PID: 371 Comm: syz.2.17 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc90000ab6d88 EFLAGS: 00010246 RAX: 1ffffffff0ac1532 RBX: ffffc90000ab76e0 RCX: ffff88811b8f62c0 RDX: 0000000000000000 RSI: ffffc90000ab76e0 RDI: ffffc90000ab7240 RBP: ffffc90000ab6db0 R08: ffffc90000ab726f R09: ffffc90000ab726a R10: dffffc0000000000 R11: fffff52000156e4e R12: dffffc0000000000 R13: 000000000000073b R14: ffffc90000ab7240 R15: ffffffff8560a990 FS: 000055555c736500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000012ee58000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: z_erofs_decompress+0x79/0xb0 fs/erofs/decompressor.c:360 z_erofs_decompress_pcluster fs/erofs/zdata.c:1113 [inline] z_erofs_decompress_queue+0x1100/0x19e0 fs/erofs/zdata.c:1191 z_erofs_runqueue+0x116d/0x11f0 fs/erofs/zdata.c:-1 z_erofs_readpage+0x25d/0x4d0 fs/erofs/zdata.c:1604 do_read_cache_page+0x58e/0xb10 mm/filemap.c:-1 read_cache_page+0x50/0x70 mm/filemap.c:3676 read_mapping_page include/linux/pagemap.h:513 [inline] find_target_block_classic fs/erofs/namei.c:104 [inline] erofs_namei+0x12a/0xf80 fs/erofs/namei.c:184 erofs_lookup+0xa5/0x260 fs/erofs/namei.c:228 __lookup_slow+0x2b8/0x410 fs/namei.c:1671 lookup_slow+0x57/0x70 fs/namei.c:1688 walk_component+0x326/0x460 fs/namei.c:1984 link_path_walk+0x688/0xde0 fs/namei.c:-1 path_parentat fs/namei.c:2510 [inline] __filename_parentat+0x254/0x690 fs/namei.c:2534 filename_parentat fs/namei.c:2552 [inline] filename_create+0xd5/0x440 fs/namei.c:3824 do_mkdirat+0x5c/0x4d0 fs/namei.c:4088 __do_sys_mkdir fs/namei.c:4118 [inline] __se_sys_mkdir fs/namei.c:4116 [inline] __x64_sys_mkdir+0x6e/0x80 fs/namei.c:4116 x64_sys_call+0x124/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:84 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f253636ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd1e96f568 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007f25365f4fa0 RCX: 00007f253636ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000 RBP: 00007f2536402e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f25365f4fac R14: 00007f25365f4fa0 R15: 00007f25365f4fa0 Modules linked in: CR2: 0000000000000000 ---[ end trace 22711f19847065a3 ]--- RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc90000ab6d88 EFLAGS: 00010246 RAX: 1ffffffff0ac1532 RBX: ffffc90000ab76e0 RCX: ffff88811b8f62c0 RDX: 0000000000000000 RSI: ffffc90000ab76e0 RDI: ffffc90000ab7240 RBP: ffffc90000ab6db0 R08: ffffc90000ab726f R09: ffffc90000ab726a R10: dffffc0000000000 R11: fffff52000156e4e R12: dffffc0000000000 R13: 000000000000073b R14: ffffc90000ab7240 R15: ffffffff8560a990 FS: 000055555c736500(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000012ee58000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400