Re: [syzbot] [dri?] [media?] general protection fault in udmabuf_create (2)

[syzbot <syzbot+40c7dad27267f61839d4@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    9d99040b1bc8 Add linux-next specific files for 20240529
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14c083e6980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=735e953fee00ec19
dashboard link: https://syzkaller.appspot.com/bug?extid=40c7dad27267f61839d4
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=176b79d2980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10266eaa980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f0deeb27b28b/disk-9d99040b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5acd2205cee1/vmlinux-9d99040b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/222eebb6b9d8/bzImage-9d99040b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+40c7dad27267f61839d4@syzkaller.appspotmail.com

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: 1 PID: 5101 Comm: syz-executor479 Not tainted 6.10.0-rc1-next-20240529-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:PageTail include/linux/page-flags.h:284 [inline]
RIP: 0010:const_folio_flags include/linux/page-flags.h:312 [inline]
RIP: 0010:folio_test_head include/linux/page-flags.h:837 [inline]
RIP: 0010:folio_test_large include/linux/page-flags.h:858 [inline]
RIP: 0010:folio_nr_pages include/linux/mm.h:2076 [inline]
RIP: 0010:udmabuf_create+0xa54/0x11c0 drivers/dma-buf/udmabuf.c:376
Code: 01 00 00 48 8b 44 24 70 42 80 3c 28 00 48 8b 5c 24 68 74 08 48 89 df e8 9a 63 ed fb 4c 8b 3b 49 8d 5f 08 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 7d 63 ed fb 48 8b 1b 48 89 de 48
RSP: 0018:ffffc9000357fbe0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffff888022207028 RDI: ffff8880295ee248
RBP: ffffc9000357fd70 R08: ffffffff8fad8daf R09: 1ffffffff1f5b1b5
R10: dffffc0000000000 R11: fffffbfff1f5b1b6 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888022207028 R15: 0000000000000000
FS:  00005555645a9480(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feee7c0f0d0 CR3: 0000000022b26000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 udmabuf_ioctl_create drivers/dma-buf/udmabuf.c:420 [inline]
 udmabuf_ioctl+0x304/0x4f0 drivers/dma-buf/udmabuf.c:451
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feee7b981b9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffda54957e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007feee7b981b9
RDX: 00000000200002c0 RSI: 0000000040187542 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000001
R13: 431bde82d7b634db R14: 00007ffda5495820 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:PageTail include/linux/page-flags.h:284 [inline]
RIP: 0010:const_folio_flags include/linux/page-flags.h:312 [inline]
RIP: 0010:folio_test_head include/linux/page-flags.h:837 [inline]
RIP: 0010:folio_test_large include/linux/page-flags.h:858 [inline]
RIP: 0010:folio_nr_pages include/linux/mm.h:2076 [inline]
RIP: 0010:udmabuf_create+0xa54/0x11c0 drivers/dma-buf/udmabuf.c:376
Code: 01 00 00 48 8b 44 24 70 42 80 3c 28 00 48 8b 5c 24 68 74 08 48 89 df e8 9a 63 ed fb 4c 8b 3b 49 8d 5f 08 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 7d 63 ed fb 48 8b 1b 48 89 de 48
RSP: 0018:ffffc9000357fbe0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000008 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: ffff888022207028 RDI: ffff8880295ee248
RBP: ffffc9000357fd70 R08: ffffffff8fad8daf R09: 1ffffffff1f5b1b5
R10: dffffc0000000000 R11: fffffbfff1f5b1b6 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888022207028 R15: 0000000000000000
FS:  00005555645a9480(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000005fdeb8 CR3: 0000000022b26000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	01 00                	add    %eax,(%rax)
   2:	00 48 8b             	add    %cl,-0x75(%rax)
   5:	44 24 70             	rex.R and $0x70,%al
   8:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
   d:	48 8b 5c 24 68       	mov    0x68(%rsp),%rbx
  12:	74 08                	je     0x1c
  14:	48 89 df             	mov    %rbx,%rdi
  17:	e8 9a 63 ed fb       	call   0xfbed63b6
  1c:	4c 8b 3b             	mov    (%rbx),%r15
  1f:	49 8d 5f 08          	lea    0x8(%r15),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 7d 63 ed fb       	call   0xfbed63b6
  39:	48 8b 1b             	mov    (%rbx),%rbx
  3c:	48 89 de             	mov    %rbx,%rsi
  3f:	48                   	rex.W


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