EXT4-fs error (device loop2): __ext4_ext_dirty:206: inode #2: comm syz.2.920: mark_inode_dirty error BUG: unable to handle page fault for address: ffffffffffffff93 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 7012067 P4D 7012067 PUD 7014067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 3624 Comm: syz.2.920 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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+0x2e59/0x6200 fs/ext4/extents.c:4497 Code: 40 01 00 00 4d 85 f6 0f 84 bc 00 00 00 48 89 5c 24 20 49 8d 7e 08 48 89 f8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 38 16 00 00 <41> 0f b7 46 08 c1 e0 04 48 8d 04 40 48 89 44 24 08 49 8d 46 28 48 RSP: 0018:ffffc900024a7020 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc9000165a000 RSI: 000000000007ffff RDI: ffffffffffffff93 RBP: ffffc900024a72d0 R08: ffff888116772c33 R09: 1ffff11022cee586 R10: dffffc0000000000 R11: ffffed1022cee587 R12: dffffc0000000000 R13: 1ffff92000494e30 R14: ffffffffffffff8b R15: 0000000000000001 FS: 00007fc1cacd26c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffff93 CR3: 000000012f30a000 CR4: 00000000003526b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ext4_map_blocks+0x9d8/0x1b70 fs/ext4/inode.c:679 ext4_getblk+0x1cc/0x6e0 fs/ext4/inode.c:890 ext4_bread+0x2b/0x170 fs/ext4/inode.c:946 ext4_append+0x2be/0x560 fs/ext4/namei.c:83 ext4_add_entry+0x8eb/0xdb0 fs/ext4/namei.c:2511 ext4_add_nondir+0x97/0x270 fs/ext4/namei.c:2845 ext4_create+0x2e6/0x470 fs/ext4/namei.c:2891 lookup_open fs/namei.c:3489 [inline] open_last_lookups fs/namei.c:3557 [inline] path_openat+0x11ec/0x2f80 fs/namei.c:3787 do_filp_open+0x1f1/0x430 fs/namei.c:3817 do_sys_openat2+0x15e/0x810 fs/open.c:1343 do_sys_open fs/open.c:1359 [inline] __do_sys_creat fs/open.c:1437 [inline] __se_sys_creat fs/open.c:1431 [inline] __x64_sys_creat+0x8e/0xb0 fs/open.c:1431 x64_sys_call+0x116/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:86 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fc1c9d9ce59 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:00007fc1cacd2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007fc1ca015fa0 RCX: 00007fc1c9d9ce59 RDX: 0000000000000000 RSI: 0000000000000018 RDI: 00002000000000c0 RBP: 00007fc1c9e32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc1ca016038 R14: 00007fc1ca015fa0 R15: 00007ffcc2f06c98 Modules linked in: CR2: ffffffffffffff93 ---[ 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+0x2e59/0x6200 fs/ext4/extents.c:4497 Code: 40 01 00 00 4d 85 f6 0f 84 bc 00 00 00 48 89 5c 24 20 49 8d 7e 08 48 89 f8 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 38 16 00 00 <41> 0f b7 46 08 c1 e0 04 48 8d 04 40 48 89 44 24 08 49 8d 46 28 48 RSP: 0018:ffffc900024a7020 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc9000165a000 RSI: 000000000007ffff RDI: ffffffffffffff93 RBP: ffffc900024a72d0 R08: ffff888116772c33 R09: 1ffff11022cee586 R10: dffffc0000000000 R11: ffffed1022cee587 R12: dffffc0000000000 R13: 1ffff92000494e30 R14: ffffffffffffff8b R15: 0000000000000001 FS: 00007fc1cacd26c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffff93 CR3: 000000012f30a000 CR4: 00000000003526b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 40 01 00 rex add %eax,(%rax) 3: 00 4d 85 add %cl,-0x7b(%rbp) 6: f6 0f 84 testb $0x84,(%rdi) 9: bc 00 00 00 48 mov $0x48000000,%esp e: 89 5c 24 20 mov %ebx,0x20(%rsp) 12: 49 8d 7e 08 lea 0x8(%r14),%rdi 16: 48 89 f8 mov %rdi,%rax 19: 48 c1 e8 03 shr $0x3,%rax 1d: 42 0f b6 04 20 movzbl (%rax,%r12,1),%eax 22: 84 c0 test %al,%al 24: 0f 85 38 16 00 00 jne 0x1662 * 2a: 41 0f b7 46 08 movzwl 0x8(%r14),%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 08 mov %rax,0x8(%rsp) 3b: 49 8d 46 28 lea 0x28(%r14),%rax 3f: 48 rex.W