EXT4-fs (loop1): This should not happen!! Data will be lost BUG: unable to handle page fault for address: ffffffffffffffec #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD cf35067 P4D cf35067 PUD cf37067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 11907 Comm: syz.1.1626 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline] RIP: 0010:ext4_free_ext_path fs/ext4/extents.c:128 [inline] RIP: 0010:ext4_ext_map_blocks+0x2d00/0x6800 fs/ext4/extents.c:4494 Code: 8b 7c 24 10 4d 85 ff 0f 84 bd 00 00 00 e8 78 dc 58 ff 49 8d 7f 08 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 3d 1e 00 00 <41> 0f b7 47 08 c1 e0 04 48 8d 04 40 48 89 44 24 10 4d 89 fc 49 8d RSP: 0018:ffffc9000bfaf040 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffc9000bfaf4f0 RCX: 0000000000080000 RDX: ffffc9000d87d000 RSI: 0000000000001eba RDI: ffffffffffffffec RBP: ffffc9000bfaf2f0 R08: ffffffff911c359f R09: 1ffffffff22386b3 R10: dffffc0000000000 R11: fffffbfff22386b4 R12: 0000000000000001 R13: 1ffff920017f5e34 R14: dffffc0000000000 R15: ffffffffffffffe4 FS: 00007fa1cbc676c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffec CR3: 00000000754aa000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000001800 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: ext4_map_blocks+0x9e2/0x1b80 fs/ext4/inode.c:652 _ext4_get_block+0x1eb/0x480 fs/ext4/inode.c:794 ext4_get_block_unwritten+0x2e/0x100 fs/ext4/inode.c:827 ext4_block_write_begin+0x55d/0x14f0 fs/ext4/inode.c:1091 ext4_write_begin+0x5de/0x1070 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x2df/0x9c0 fs/ext4/inode.c:2908 generic_perform_write+0x2fe/0x5c0 mm/filemap.c:4031 ext4_buffered_write_iter+0xcc/0x350 fs/ext4/file.c:299 ext4_file_write_iter+0x1d9/0x1880 fs/ext4/file.c:-1 call_write_iter include/linux/fs.h:2018 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x46c/0x990 fs/read_write.c:584 ksys_pwrite64 fs/read_write.c:699 [inline] __do_sys_pwrite64 fs/read_write.c:709 [inline] __se_sys_pwrite64 fs/read_write.c:706 [inline] __x64_sys_pwrite64+0x19b/0x230 fs/read_write.c:706 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa1cad9c819 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:00007fa1cbc67028 EFLAGS: 00000246 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00007fa1cb015fa0 RCX: 00007fa1cad9c819 RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000007 RBP: 00007fa1cae32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000e7c R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa1cb016038 R14: 00007fa1cb015fa0 R15: 00007fffabfb4368 Modules linked in: CR2: ffffffffffffffec ---[ end trace 0000000000000000 ]--- RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline] RIP: 0010:ext4_free_ext_path fs/ext4/extents.c:128 [inline] RIP: 0010:ext4_ext_map_blocks+0x2d00/0x6800 fs/ext4/extents.c:4494 Code: 8b 7c 24 10 4d 85 ff 0f 84 bd 00 00 00 e8 78 dc 58 ff 49 8d 7f 08 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 3d 1e 00 00 <41> 0f b7 47 08 c1 e0 04 48 8d 04 40 48 89 44 24 10 4d 89 fc 49 8d RSP: 0018:ffffc9000bfaf040 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffc9000bfaf4f0 RCX: 0000000000080000 RDX: ffffc9000d87d000 RSI: 0000000000001eba RDI: ffffffffffffffec RBP: ffffc9000bfaf2f0 R08: ffffffff911c359f R09: 1ffffffff22386b3 R10: dffffc0000000000 R11: fffffbfff22386b4 R12: 0000000000000001 R13: 1ffff920017f5e34 R14: dffffc0000000000 R15: ffffffffffffffe4 FS: 00007fa1cbc676c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffec CR3: 00000000754aa000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000001800 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 8b 7c 24 10 mov 0x10(%rsp),%edi 4: 4d 85 ff test %r15,%r15 7: 0f 84 bd 00 00 00 je 0xca d: e8 78 dc 58 ff call 0xff58dc8a 12: 49 8d 7f 08 lea 0x8(%r15),%rdi 16: 48 89 f8 mov %rdi,%rax 19: 48 c1 e8 03 shr $0x3,%rax 1d: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax 22: 84 c0 test %al,%al 24: 0f 85 3d 1e 00 00 jne 0x1e67 * 2a: 41 0f b7 47 08 movzwl 0x8(%r15),%eax <-- trapping instruction 2f: c1 e0 04 shl $0x4,%eax 32: 48 8d 04 40 lea (%rax,%rax,2),%rax 36: 48 89 44 24 10 mov %rax,0x10(%rsp) 3b: 4d 89 fc mov %r15,%r12 3e: 49 rex.WB 3f: 8d .byte 0x8d