erofs: (device loop0): 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 11dc74067 P4D 11dc74067 PUD 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 1 PID: 2160 Comm: syz.0.431 Tainted: G W 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:ffffc90001016da8 EFLAGS: 00010246 RAX: 1ffffffff0a7c1ae RBX: ffffc90001017700 RCX: 0000000000080000 RDX: ffffc9000751f000 RSI: ffffc90001017700 RDI: ffffc90001017260 RBP: ffffc90001016dd0 R08: ffffc9000101728f R09: ffffc9000101728a R10: dffffc0000000000 R11: fffff52000202e52 R12: dffffc0000000000 R13: 000000000000073b R14: ffffc90001017260 R15: ffffffff853e0d70 FS: 00007fd40eb806c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000010fb86000 CR4: 00000000003526a0 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+0x10ff/0x1a90 fs/erofs/zdata.c:1188 z_erofs_runqueue+0x11fe/0x1280 fs/erofs/zdata.c:-1 z_erofs_readpage+0x225/0x500 fs/erofs/zdata.c:1533 do_read_cache_page+0x69b/0xaa0 mm/filemap.c:-1 read_cache_page+0x50/0x70 mm/filemap.c:3296 read_mapping_page include/linux/pagemap.h:498 [inline] find_target_block_classic fs/erofs/namei.c:104 [inline] erofs_namei+0x162/0x10d0 fs/erofs/namei.c:184 erofs_lookup+0xa5/0x260 fs/erofs/namei.c:228 __lookup_slow+0x2b8/0x410 fs/namei.c:1648 lookup_slow+0x57/0x70 fs/namei.c:1665 walk_component+0x325/0x460 fs/namei.c:1960 link_path_walk+0x5b2/0xba0 fs/namei.c:-1 path_parentat fs/namei.c:2487 [inline] filename_parentat+0x200/0x5e0 fs/namei.c:2509 filename_create+0xd4/0x680 fs/namei.c:3598 user_path_create fs/namei.c:3673 [inline] do_mkdirat+0x5e/0x340 fs/namei.c:3813 __do_sys_mkdir fs/namei.c:3836 [inline] __se_sys_mkdir fs/namei.c:3834 [inline] __x64_sys_mkdir+0x60/0x70 fs/namei.c:3834 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fd410167e59 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:00007fd40eb80028 EFLAGS: 00000246 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007fd4103e1180 RCX: 00007fd410167e59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000 RBP: 00007fd4101fdd6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd4103e1218 R14: 00007fd4103e1180 R15: 00007ffd9fde02c8 Modules linked in: CR2: 0000000000000000 ---[ end trace 7a08aa5fef5d80bc ]--- RIP: 0010:0x0 Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. RSP: 0018:ffffc90001016da8 EFLAGS: 00010246 RAX: 1ffffffff0a7c1ae RBX: ffffc90001017700 RCX: 0000000000080000 RDX: ffffc9000751f000 RSI: ffffc90001017700 RDI: ffffc90001017260 RBP: ffffc90001016dd0 R08: ffffc9000101728f R09: ffffc9000101728a R10: dffffc0000000000 R11: fffff52000202e52 R12: dffffc0000000000 R13: 000000000000073b R14: ffffc90001017260 R15: ffffffff853e0d70 FS: 00007fd40eb806c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000010fb86000 CR4: 00000000003526a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400