syzbot


general protection fault in bio_iov_iter_get_pages

Status: upstream: reported C repro on 2025/09/07 07:11
Subsystems: block
[Documentation on labels]
Reported-by: syzbot+b253ade8e1751d90a7a9@syzkaller.appspotmail.com
First crash: 19h14m, last: 9h07m
Cause bisection: introduced by (bisect log) :
commit db076b5db550aa34169dceee81d0974c7b2a2482
Author: David Hildenbrand <david@redhat.com>
Date: Mon Sep 1 15:03:40 2025 +0000

  mm/gup: remove record_subpages()

Crash: BUG: unable to handle kernel NULL pointer dereference in bio_iov_iter_get_pages (log)
Repro: C syz .config
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [block?] general protection fault in bio_iov_iter_get_pages 1 (3) 2025/09/07 09:32
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/09/07 08:19 24m hdanton@sina.com patch linux-next OK log

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 UID: 0 PID: 6039 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:_compound_head include/linux/page-flags.h:284 [inline]
RIP: 0010:get_contig_folio_len block/bio.c:1183 [inline]
RIP: 0010:__bio_iov_iter_get_pages block/bio.c:1269 [inline]
RIP: 0010:bio_iov_iter_get_pages+0x80e/0x11c0 block/bio.c:1336
Code: 30 4c 89 ac 24 c0 00 00 00 49 89 dd 48 8b 04 d9 48 89 44 24 18 48 8d 58 08 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 94 c6 7c fd 48 8b 1b 48 89 de 48 83
RSP: 0018:ffffc90002fe73e0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002fe7590 R08: ffffea0001668007 R09: 1ffffd40002cd000
R10: dffffc0000000000 R11: fffff940002cd001 R12: 00000000000ad000
R13: 00000000000000ad R14: 0000000000001000 R15: 1ffff1100f138a2d
FS:  0000555564b88500(0000) GS:ffff888125af9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0bc759e000 CR3: 0000000077cd4000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __blkdev_direct_IO+0x60b/0xee0 block/fops.c:215
 blkdev_direct_IO+0x120f/0x1730 block/fops.c:434
 blkdev_direct_write+0x7c/0x140 block/fops.c:719
 blkdev_write_iter+0x547/0x710 block/fops.c:787
 aio_write+0x535/0x7a0 fs/aio.c:1634
 __io_submit_one fs/aio.c:-1 [inline]
 io_submit_one+0x78b/0x1310 fs/aio.c:2053
 __do_sys_io_submit fs/aio.c:2112 [inline]
 __se_sys_io_submit+0x185/0x2f0 fs/aio.c:2082
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0bc678ebe9
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:00007fffb538a3e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1
RAX: ffffffffffffffda RBX: 00007f0bc69c5fa0 RCX: 00007f0bc678ebe9
RDX: 00002000000000c0 RSI: 00000000000000f3 RDI: 00007f0bc759e000
RBP: 00007f0bc6811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0bc69c5fa0 R14: 00007f0bc69c5fa0 R15: 0000000000000003
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:_compound_head include/linux/page-flags.h:284 [inline]
RIP: 0010:get_contig_folio_len block/bio.c:1183 [inline]
RIP: 0010:__bio_iov_iter_get_pages block/bio.c:1269 [inline]
RIP: 0010:bio_iov_iter_get_pages+0x80e/0x11c0 block/bio.c:1336
Code: 30 4c 89 ac 24 c0 00 00 00 49 89 dd 48 8b 04 d9 48 89 44 24 18 48 8d 58 08 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 94 c6 7c fd 48 8b 1b 48 89 de 48 83
RSP: 0018:ffffc90002fe73e0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002fe7590 R08: ffffea0001668007 R09: 1ffffd40002cd000
R10: dffffc0000000000 R11: fffff940002cd001 R12: 00000000000ad000
R13: 00000000000000ad R14: 0000000000001000 R15: 1ffff1100f138a2d
FS:  0000555564b88500(0000) GS:ffff888125af9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0042bc000 CR3: 0000000077cd4000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	30 4c 89 ac          	xor    %cl,-0x54(%rcx,%rcx,4)
   4:	24 c0                	and    $0xc0,%al
   6:	00 00                	add    %al,(%rax)
   8:	00 49 89             	add    %cl,-0x77(%rcx)
   b:	dd 48 8b             	fisttpll -0x75(%rax)
   e:	04 d9                	add    $0xd9,%al
  10:	48 89 44 24 18       	mov    %rax,0x18(%rsp)
  15:	48 8d 58 08          	lea    0x8(%rax),%rbx
  19:	48 89 d8             	mov    %rbx,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 94 c6 7c fd       	call   0xfd7cc6cc
  38:	48 8b 1b             	mov    (%rbx),%rbx
  3b:	48 89 de             	mov    %rbx,%rsi
  3e:	48                   	rex.W
  3f:	83                   	.byte 0x83

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/07 05:20 linux-next be5d4872e528 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in bio_iov_iter_get_pages
2025/09/07 03:09 linux-next be5d4872e528 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in bio_iov_iter_get_pages
2025/09/07 01:42 linux-next be5d4872e528 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in bio_iov_iter_get_pages
2025/09/07 00:16 linux-next be5d4872e528 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in bio_iov_iter_get_pages
2025/09/06 22:43 linux-next be5d4872e528 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in bio_iov_iter_get_pages
2025/09/06 21:08 linux-next be5d4872e528 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in bio_iov_iter_get_pages
2025/09/06 19:13 linux-next be5d4872e528 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in bio_iov_iter_get_pages
* Struck through repros no longer work on HEAD.