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 123e22067 P4D 123e22067 PUD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 0 PID: 373 Comm: syz.2.17 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc9000400eb48 EFLAGS: 00010246 RAX: 1ffffffff0ac1962 RBX: ffffc9000400f4a0 RCX: ffff88811172e2c0 RDX: 0000000000000000 RSI: ffffc9000400f4a0 RDI: ffffc9000400f000 RBP: ffffc9000400eb70 R08: ffffc9000400f02f R09: ffffc9000400f02a R10: dffffc0000000000 R11: fffff52000801e06 R12: dffffc0000000000 R13: 000000000000073b R14: ffffc9000400f000 R15: ffffffff8560cb10 FS: 000055557dfaa500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000012ee91000 CR4: 00000000003506b0 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:1110 [inline] z_erofs_decompress_queue+0x10d4/0x1a30 fs/erofs/zdata.c:1188 z_erofs_runqueue+0x113e/0x11c0 fs/erofs/zdata.c:-1 z_erofs_readpage+0x25d/0x4d0 fs/erofs/zdata.c:1601 do_read_cache_page+0x66e/0xa30 mm/filemap.c:-1 read_cache_page+0x50/0x70 mm/filemap.c:3659 read_mapping_page include/linux/pagemap.h:513 [inline] find_target_block_classic fs/erofs/namei.c:104 [inline] erofs_namei+0x152/0xfa0 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+0x325/0x460 fs/namei.c:1984 link_path_walk+0x665/0xd60 fs/namei.c:-1 path_openat+0x27b/0x2f20 fs/namei.c:3746 do_filp_open+0x1e2/0x410 fs/namei.c:3777 do_sys_openat2+0x15e/0x7f0 fs/open.c:1236 do_sys_open fs/open.c:1252 [inline] __do_sys_open fs/open.c:1260 [inline] __se_sys_open fs/open.c:1256 [inline] __x64_sys_open+0x11c/0x140 fs/open.c:1256 x64_sys_call+0x3fc/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:3 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: 0033:0x7fb5425e5dd9 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:00007ffce6f6e8f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fb54285efa0 RCX: 00007fb5425e5dd9 RDX: 0000000000000000 RSI: 00000000001a1342 RDI: 0000200000000000 RBP: 00007fb54267bd69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb54285efac R14: 00007fb54285efa0 R15: 00007fb54285efa0 Modules linked in: CR2: 0000000000000000 ---[ end trace 1ba30838848932bb ]--- RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc9000400eb48 EFLAGS: 00010246 RAX: 1ffffffff0ac1962 RBX: ffffc9000400f4a0 RCX: ffff88811172e2c0 RDX: 0000000000000000 RSI: ffffc9000400f4a0 RDI: ffffc9000400f000 RBP: ffffc9000400eb70 R08: ffffc9000400f02f R09: ffffc9000400f02a R10: dffffc0000000000 R11: fffff52000801e06 R12: dffffc0000000000 R13: 000000000000073b R14: ffffc9000400f000 R15: ffffffff8560cb10 FS: 000055557dfaa500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000012ee91000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400