Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in skb_queue_purge_reason (2)

[syzbot <syzbot+683f8cb11b94b1824c77@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    40b8e93e17bf Add linux-next specific files for 20250204
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=113d5d18580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ec880188a87c6aad
dashboard link: https://syzkaller.appspot.com/bug?extid=683f8cb11b94b1824c77
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=10b7eeb0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12f74f64580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ccdfef06f59f/disk-40b8e93e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b339eaf8dcfd/vmlinux-40b8e93e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ae1a0f1c3c80/bzImage-40b8e93e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+683f8cb11b94b1824c77@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: 0 UID: 0 PID: 5833 Comm: syz-executor346 Not tainted 6.14.0-rc1-next-20250204-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:skb_queue_empty_lockless include/linux/skbuff.h:1887 [inline]
RIP: 0010:skb_queue_purge_reason+0xaa/0x500 net/core/skbuff.c:3936
Code: 89 44 24 78 42 c6 44 30 13 f3 e8 81 76 05 f8 48 8d bc 24 b0 00 00 00 ba 48 00 00 00 31 f6 e8 0d f2 6b f8 4d 89 ef 49 c1 ef 03 <43> 80 3c 37 00 74 08 4c 89 ef e8 27 ef 6b f8 49 8b 45 00 4c 39 e8
RSP: 0018:ffffc90003d17880 EFLAGS: 00010202
RAX: ffffc90003d17930 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90003d17978
RBP: ffffc90003d179f0 R08: ffffc90003d17977 R09: 0000000000000000
R10: ffffc90003d17930 R11: fffff520007a2f2f R12: dffffc0000000000
R13: 0000000000000008 R14: dffffc0000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055867393d608 CR3: 000000000e738000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 skb_queue_purge include/linux/skbuff.h:3364 [inline]
 mrvl_close+0x8e/0x120 drivers/bluetooth/hci_mrvl.c:100
 hci_uart_tty_close+0x205/0x290 drivers/bluetooth/hci_ldisc.c:557
 tty_ldisc_kill+0xa3/0x1a0 drivers/tty/tty_ldisc.c:613
 tty_ldisc_release+0x1a1/0x200 drivers/tty/tty_ldisc.c:781
 tty_release_struct+0x2b/0xe0 drivers/tty/tty_io.c:1690
 tty_release+0xd06/0x12c0 drivers/tty/tty_io.c:1861
 __fput+0x3e9/0x9f0 fs/file_table.c:448
 task_work_run+0x24f/0x310 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xa2a/0x28e0 kernel/exit.c:938
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 __do_sys_exit_group kernel/exit.c:1098 [inline]
 __se_sys_exit_group kernel/exit.c:1096 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1096
 x64_sys_call+0x26a8/0x26b0 arch/x86/include/generated/asm/syscalls_64.h:232
 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: 0033:0x7f794f6cfc79
Code: Unable to access opcode bytes at 0x7f794f6cfc4f.
RSP: 002b:00007fff04322488 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f794f6cfc79
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 00007f794f74a270 R08: ffffffffffffffb8 R09: 00007fff043226a8
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f794f74a270
R13: 0000000000000000 R14: 00007f794f74acc0 R15: 00007f794f6a1a60
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:skb_queue_empty_lockless include/linux/skbuff.h:1887 [inline]
RIP: 0010:skb_queue_purge_reason+0xaa/0x500 net/core/skbuff.c:3936
Code: 89 44 24 78 42 c6 44 30 13 f3 e8 81 76 05 f8 48 8d bc 24 b0 00 00 00 ba 48 00 00 00 31 f6 e8 0d f2 6b f8 4d 89 ef 49 c1 ef 03 <43> 80 3c 37 00 74 08 4c 89 ef e8 27 ef 6b f8 49 8b 45 00 4c 39 e8
RSP: 0018:ffffc90003d17880 EFLAGS: 00010202
RAX: ffffc90003d17930 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90003d17978
RBP: ffffc90003d179f0 R08: ffffc90003d17977 R09: 0000000000000000
R10: ffffc90003d17930 R11: fffff520007a2f2f R12: dffffc0000000000
R13: 0000000000000008 R14: dffffc0000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055867393d608 CR3: 000000000e738000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	89 44 24 78          	mov    %eax,0x78(%rsp)
   4:	42 c6 44 30 13 f3    	movb   $0xf3,0x13(%rax,%r14,1)
   a:	e8 81 76 05 f8       	call   0xf8057690
   f:	48 8d bc 24 b0 00 00 	lea    0xb0(%rsp),%rdi
  16:	00
  17:	ba 48 00 00 00       	mov    $0x48,%edx
  1c:	31 f6                	xor    %esi,%esi
  1e:	e8 0d f2 6b f8       	call   0xf86bf230
  23:	4d 89 ef             	mov    %r13,%r15
  26:	49 c1 ef 03          	shr    $0x3,%r15
* 2a:	43 80 3c 37 00       	cmpb   $0x0,(%r15,%r14,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ef             	mov    %r13,%rdi
  34:	e8 27 ef 6b f8       	call   0xf86bef60
  39:	49 8b 45 00          	mov    0x0(%r13),%rax
  3d:	4c 39 e8             	cmp    %r13,%rax


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