[syzbot] [net?] [bcachefs?] general protection fault in __alloc_skb

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    69e858e0b8b2 Merge tag 'uml-for-linus-6.14-rc1' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16f4dddf980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d033b14aeef39158
dashboard link: https://syzkaller.appspot.com/bug?extid=095590432e94610ef0e5
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=17974518580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-69e858e0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a53b888c1f3f/vmlinux-69e858e0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6b5e17edafc0/bzImage-69e858e0.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f903aea5a6cc/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+095590432e94610ef0e5@xxxxxxxxxxxxxxxxxxxxxxxxx

Oops: general protection fault, probably for non-canonical address 0x76a030f00000485: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 1077 Comm: kworker/u4:10 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:get_freepointer mm/slub.c:504 [inline]
RIP: 0010:get_freepointer_safe mm/slub.c:532 [inline]
RIP: 0010:__slab_alloc_node mm/slub.c:3993 [inline]
RIP: 0010:slab_alloc_node mm/slub.c:4152 [inline]
RIP: 0010:kmem_cache_alloc_node_noprof+0xec/0x380 mm/slub.c:4216
Code: 0f 84 8a 01 00 00 41 83 f8 ff 74 1a 48 8b 03 48 83 f8 ff 0f 84 8f 02 00 00 48 c1 e8 3a 41 39 c0 0f 85 6a 01 00 00 41 8b 46 28 <4a> 8b 1c 28 49 8d 4c 24 08 49 8b 36 4c 89 e8 4c 89 e2 65 48 0f c7
RSP: 0018:ffffc900026ef908 EFLAGS: 00010246
RAX: 0000000000000078 RBX: ffffea0000f49540 RCX: 0000000000046a30
RDX: 0000000000000000 RSI: 00000000000000f0 RDI: ffffffff8ea52d00
RBP: 00000000ffffffff R08: 00000000ffffffff R09: fffff520004ddf38
R10: dffffc0000000000 R11: fffff520004ddf38 R12: 00000000000d7b48
R13: 076a030f0000040d R14: ffff88801b7a18c0 R15: 0000000000000820
FS:  0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4588978ab8 CR3: 0000000059eac000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __alloc_skb+0x1c3/0x440 net/core/skbuff.c:668
 alloc_skb include/linux/skbuff.h:1331 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline]
 nsim_dev_trap_report_work+0x261/0xb50 drivers/net/netdevsim/dev.c:851
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3317
 worker_thread+0x870/0xd30 kernel/workqueue.c:3398
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Modules linked in:
----------------
Code disassembly (best guess):
   0:	0f 84 8a 01 00 00    	je     0x190
   6:	41 83 f8 ff          	cmp    $0xffffffff,%r8d
   a:	74 1a                	je     0x26
   c:	48 8b 03             	mov    (%rbx),%rax
   f:	48 83 f8 ff          	cmp    $0xffffffffffffffff,%rax
  13:	0f 84 8f 02 00 00    	je     0x2a8
  19:	48 c1 e8 3a          	shr    $0x3a,%rax
  1d:	41 39 c0             	cmp    %eax,%r8d
  20:	0f 85 6a 01 00 00    	jne    0x190
  26:	41 8b 46 28          	mov    0x28(%r14),%eax
* 2a:	4a 8b 1c 28          	mov    (%rax,%r13,1),%rbx <-- trapping instruction
  2e:	49 8d 4c 24 08       	lea    0x8(%r12),%rcx
  33:	49 8b 36             	mov    (%r14),%rsi
  36:	4c 89 e8             	mov    %r13,%rax
  39:	4c 89 e2             	mov    %r12,%rdx
  3c:	65                   	gs
  3d:	48                   	rex.W
  3e:	0f                   	.byte 0xf
  3f:	c7                   	.byte 0xc7


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