syzbot

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 UID: 0 PID: 387 Comm: syz.2.21 Not tainted syzkaller #0 0b5ffdee5fcd2f7749818d1ff954e9c21353764e
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:pipe_buf_release include/linux/pipe_fs_i.h:219 [inline]
RIP: 0010:iter_file_splice_write+0xace/0x11b0 fs/splice.c:759
Code: 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 67 d6 e6 ff 49 8b 1e 49 c7 06 00 00 00 00 48 83 c3 08 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 43 d6 e6 ff 4c 8b 1b 48 8b 3c 24
RSP: 0018:ffffc9000109f820 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: ffff888115c63900
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 7ffffffffffffffb
RBP: ffffc9000109fa40 R08: ffff8881f6e72240 R09: 1ffff1103edce448
R10: 1ffff1103edce44b R11: 0000000000000fd8 R12: dffffc0000000000
R13: 7ffffffffffffffb R14: ffff8881158fb838 R15: ffff8881158fb828
FS:  000055557e4b1500(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffec75b7da8 CR3: 0000000115b00000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x279/0x4b0 fs/splice.c:1164
 splice_direct_to_actor+0x4fb/0xbc0 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0x182/0x270 fs/splice.c:1233
 do_sendfile+0x5c8/0xfb0 fs/read_write.c:1400
 __do_sys_sendfile64 fs/read_write.c:1467 [inline]
 __se_sys_sendfile64 fs/read_write.c:1453 [inline]
 __x64_sys_sendfile64+0x193/0x1f0 fs/read_write.c:1453
 x64_sys_call+0xa26/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f367fd8f6c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffec75b7bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f367ffe5fa0 RCX: 00007f367fd8f6c9
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000007
RBP: 00007f367fe11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f367ffe5fa0 R14: 00007f367ffe5fa0 R15: 0000000000000004
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:pipe_buf_release include/linux/pipe_fs_i.h:219 [inline]
RIP: 0010:iter_file_splice_write+0xace/0x11b0 fs/splice.c:759
Code: 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 67 d6 e6 ff 49 8b 1e 49 c7 06 00 00 00 00 48 83 c3 08 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 43 d6 e6 ff 4c 8b 1b 48 8b 3c 24
RSP: 0018:ffffc9000109f820 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: ffff888115c63900
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 7ffffffffffffffb
RBP: ffffc9000109fa40 R08: ffff8881f6e72240 R09: 1ffff1103edce448
R10: 1ffff1103edce44b R11: 0000000000000fd8 R12: dffffc0000000000
R13: 7ffffffffffffffb R14: ffff8881158fb838 R15: ffff8881158fb828
FS:  000055557e4b1500(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557e4cc4a8 CR3: 0000000115b00000 CR4: 00000000003526b0
----------------
Code disassembly (best guess):
   0:	89 f0                	mov    %esi,%eax
   2:	48 c1 e8 03          	shr    $0x3,%rax
   6:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
   b:	74 08                	je     0x15
   d:	4c 89 f7             	mov    %r14,%rdi
  10:	e8 67 d6 e6 ff       	call   0xffe6d67c
  15:	49 8b 1e             	mov    (%r14),%rbx
  18:	49 c7 06 00 00 00 00 	movq   $0x0,(%r14)
  1f:	48 83 c3 08          	add    $0x8,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 43 d6 e6 ff       	call   0xffe6d67c
  39:	4c 8b 1b             	mov    (%rbx),%r11
  3c:	48 8b 3c 24          	mov    (%rsp),%rdi