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: 12821 Comm: kworker/u8:8 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:bio_init block/bio.c:214 [inline]
RIP: 0010:bio_alloc_bioset+0x744/0xc10 block/bio.c:595
Code: 48 83 7c 24 20 00 0f 84 fa 00 00 00 e8 f5 ab 3a fd 4c 89 ff e8 0d 28 0d 00 e9 ed 00 00 00 e8 e3 ab 3a fd 4c 89 f8 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 ff e8 5e 26 a4 fd 49 c7 07 00 00 00 00 49
RSP: 0018:ffffc90003d9e880 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff9a8dc910 RCX: d1e25e8fd8d1e300
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff905435f7 R09: 1ffffffff20a86be
R10: dffffc0000000000 R11: fffffbfff20a86bf R12: 0000000000092800
R13: ffffffff9a8dc840 R14: 0000000000000100 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124ee1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f69046ce730 CR3: 00000000258ee000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 bio_alloc include/linux/bio.h:373 [inline]
 io_submit_init_bio fs/ext4/page-io.c:428 [inline]
 io_submit_add_bh fs/ext4/page-io.c:464 [inline]
 ext4_bio_write_folio+0x1044/0x1ea0 fs/ext4/page-io.c:603
 mpage_process_page_bufs+0x6d5/0x8e0 fs/ext4/inode.c:2194
 mpage_prepare_extent_to_map+0xe1b/0x16f0 fs/ext4/inode.c:2733
 ext4_do_writepages+0xbca/0x46e0 fs/ext4/inode.c:2874
 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3022
 do_writepages+0x32e/0x550 mm/page-writeback.c:2554
 __writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1750
 writeback_sb_inodes+0x992/0x1a20 fs/fs-writeback.c:2042
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
 wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2229
 wb_check_start_all fs/fs-writeback.c:2355 [inline]
 wb_do_writeback fs/fs-writeback.c:2381 [inline]
 wb_workfn+0x95b/0xf50 fs/fs-writeback.c:2414
 process_one_work+0x9ab/0x1780 kernel/workqueue.c:3288
 process_scheduled_works kernel/workqueue.c:3379 [inline]
 worker_thread+0xba8/0x11e0 kernel/workqueue.c:3465
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bio_init block/bio.c:214 [inline]
RIP: 0010:bio_alloc_bioset+0x744/0xc10 block/bio.c:595
Code: 48 83 7c 24 20 00 0f 84 fa 00 00 00 e8 f5 ab 3a fd 4c 89 ff e8 0d 28 0d 00 e9 ed 00 00 00 e8 e3 ab 3a fd 4c 89 f8 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 ff e8 5e 26 a4 fd 49 c7 07 00 00 00 00 49
RSP: 0018:ffffc90003d9e880 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff9a8dc910 RCX: d1e25e8fd8d1e300
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffffffff905435f7 R09: 1ffffffff20a86be
R10: dffffc0000000000 R11: fffffbfff20a86bf R12: 0000000000092800
R13: ffffffff9a8dc840 R14: 0000000000000100 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124de1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd248dec40 CR3: 000000002a782000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	48 83 7c 24 20 00    	cmpq   $0x0,0x20(%rsp)
   6:	0f 84 fa 00 00 00    	je     0x106
   c:	e8 f5 ab 3a fd       	call   0xfd3aac06
  11:	4c 89 ff             	mov    %r15,%rdi
  14:	e8 0d 28 0d 00       	call   0xd2826
  19:	e9 ed 00 00 00       	jmp    0x10b
  1e:	e8 e3 ab 3a fd       	call   0xfd3aac06
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 ff             	mov    %r15,%rdi
  33:	e8 5e 26 a4 fd       	call   0xfda42696
  38:	49 c7 07 00 00 00 00 	movq   $0x0,(%r15)
  3f:	49                   	rex.WB