Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 9063 Comm: syz.2.572 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:zcomp_stream_get+0x33/0xa0 drivers/block/zram/zcomp.c:113
Code: 00 00 00 00 fc ff df 41 54 55 48 89 fd 53 49 89 ec 49 c1 ec 03 4d 01 ec e8 ca 87 99 fb e8 c5 87 99 fb 65 48 8b 1d c5 dd b4 0d <41> 80 3c 24 00 75 4f 48 03 5d 00 31 f6 48 89 df e8 48 c9 71 05 48
RSP: 0018:ffffc90003237498 EFLAGS: 00010287
RAX: 0000000000000739 RBX: ffff8881247ba000 RCX: ffffc90017801000
RDX: 0000000000080000 RSI: ffffffff8621825b RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff888026d23400 R15: ffffea0001dc9400
FS:  00007feb56baf6c0(0000) GS:ffff8881247ba000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32921ff8 CR3: 000000007d4fc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 zram_write_page drivers/block/zram/zram_drv.c:1866 [inline]
 zram_bvec_write drivers/block/zram/zram_drv.c:1939 [inline]
 zram_bio_write drivers/block/zram/zram_drv.c:2380 [inline]
 zram_submit_bio+0xdd4/0x1df0 drivers/block/zram/zram_drv.c:2409
 __submit_bio+0x304/0x690 block/blk-core.c:644
 __submit_bio_noacct block/blk-core.c:690 [inline]
 submit_bio_noacct_nocheck+0x852/0xd30 block/blk-core.c:753
 submit_bio_noacct+0xc20/0x1ed0 block/blk-core.c:874
 submit_bio_wait+0x110/0x250 block/bio.c:1367
 __blkdev_direct_IO_simple+0x431/0x800 block/fops.c:92
 blkdev_direct_IO+0xc59/0x2030 block/fops.c:428
 blkdev_direct_write block/fops.c:719 [inline]
 blkdev_write_iter+0x703/0xe00 block/fops.c:787
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x7d3/0x11d0 fs/read_write.c:686
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feb55d8ec29
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:00007feb56baf038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007feb55fd5fa0 RCX: 00007feb55d8ec29
RDX: 000000100000a3d9 RSI: 0000200000000400 RDI: 0000000000000003
RBP: 00007feb55e11e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007feb55fd6038 R14: 00007feb55fd5fa0 R15: 00007ffdf96b7a38
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:zcomp_stream_get+0x33/0xa0 drivers/block/zram/zcomp.c:113
Code: 00 00 00 00 fc ff df 41 54 55 48 89 fd 53 49 89 ec 49 c1 ec 03 4d 01 ec e8 ca 87 99 fb e8 c5 87 99 fb 65 48 8b 1d c5 dd b4 0d <41> 80 3c 24 00 75 4f 48 03 5d 00 31 f6 48 89 df e8 48 c9 71 05 48
RSP: 0018:ffffc90003237498 EFLAGS: 00010287
RAX: 0000000000000739 RBX: ffff8881247ba000 RCX: ffffc90017801000
RDX: 0000000000080000 RSI: ffffffff8621825b RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff888026d23400 R15: ffffea0001dc9400
FS:  00007feb56baf6c0(0000) GS:ffff8881247ba000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d219ff8 CR3: 000000007d4fc000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 6 bytes skipped:
   0:	df 41 54             	filds  0x54(%rcx)
   3:	55                   	push   %rbp
   4:	48 89 fd             	mov    %rdi,%rbp
   7:	53                   	push   %rbx
   8:	49 89 ec             	mov    %rbp,%r12
   b:	49 c1 ec 03          	shr    $0x3,%r12
   f:	4d 01 ec             	add    %r13,%r12
  12:	e8 ca 87 99 fb       	call   0xfb9987e1
  17:	e8 c5 87 99 fb       	call   0xfb9987e1
  1c:	65 48 8b 1d c5 dd b4 	mov    %gs:0xdb4ddc5(%rip),%rbx        # 0xdb4dde9
  23:	0d
* 24:	41 80 3c 24 00       	cmpb   $0x0,(%r12) <-- trapping instruction
  29:	75 4f                	jne    0x7a
  2b:	48 03 5d 00          	add    0x0(%rbp),%rbx
  2f:	31 f6                	xor    %esi,%esi
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 48 c9 71 05       	call   0x571c981
  39:	48                   	rex.W