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Date:   Sat, 25 Nov 2023 09:33:08 -0800
In-Reply-To: <8aa60891-cd52-42c0-b9a2-594d69b133fd@siddh.me>
Message-ID: <0000000000005abf1f060afd76bd@google.com>
Subject: Re: [syzbot] [net?] [nfc?] KASAN: slab-use-after-free Read in nfc_alloc_send_skb
From:   syzbot <syzbot+bbe84a4010eeea00982d@syzkaller.appspotmail.com>
To:     code@siddh.me, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com
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Precedence: bulk

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: sleeping function called from invalid context in nfc_llcp_socket_release

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5478, name: syz-executor.0
preempt_count: 2, expected: 0
RCU nest depth: 0, expected: 0
2 locks held by syz-executor.0/5478:
 #0: ffff88806cd22468 (&local->sockets.lock){++++}-{2:2}, at: nfc_llcp_socket_release+0x56/0xb90 net/nfc/llcp_core.c:90
 #1: ffff88806cd5c0b0 (slock-AF_NFC){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #1: ffff88806cd5c0b0 (slock-AF_NFC){+.+.}-{2:2}, at: nfc_llcp_socket_release+0xcb/0xb90 net/nfc/llcp_core.c:95
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 0 PID: 5478 Comm: syz-executor.0 Not tainted 6.7.0-rc2-syzkaller-00198-g7ac1c88a5daa #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 __might_resched+0x5cf/0x780 kernel/sched/core.c:10151
 __mutex_lock_common kernel/locking/mutex.c:580 [inline]
 __mutex_lock+0xc1/0xd60 kernel/locking/mutex.c:747
 nfc_llcp_sock_close net/nfc/llcp_core.c:33 [inline]
 nfc_llcp_socket_release+0x498/0xb90 net/nfc/llcp_core.c:120
 local_cleanup+0x28/0xe0 net/nfc/llcp_core.c:161
 nfc_llcp_unregister_device+0x160/0x240 net/nfc/llcp_core.c:1655
 nfc_unregister_device+0x167/0x2a0 net/nfc/core.c:1179
 virtual_ncidev_close+0x59/0x90 drivers/nfc/virtual_ncidev.c:163
 __fput+0x3cc/0xa10 fs/file_table.c:394
 __do_sys_close fs/open.c:1590 [inline]
 __se_sys_close+0x15f/0x220 fs/open.c:1575
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fe8ddc7b9da
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 03 7f 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 63 7f 02 00 8b 44 24
RSP: 002b:00007fffdaf3d080 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fe8ddc7b9da
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fe8ddd9d980 R08: 0000001b2e060000 R09: 00007fffdaf810b0
R10: 00007fffdaf81080 R11: 0000000000000293 R12: 00000000000151df
R13: ffffffffffffffff R14: 00007fe8dd800000 R15: 0000000000014e9e
 </TASK>

=============================
[ BUG: Invalid wait context ]
6.7.0-rc2-syzkaller-00198-g7ac1c88a5daa #0 Tainted: G        W         
-----------------------------
syz-executor.0/5478 is trying to lock:
ffff88806cd5c590 (&llcp_sock->lock){+.+.}-{3:3}, at: nfc_llcp_sock_close net/nfc/llcp_core.c:33 [inline]
ffff88806cd5c590 (&llcp_sock->lock){+.+.}-{3:3}, at: nfc_llcp_socket_release+0x498/0xb90 net/nfc/llcp_core.c:120
other info that might help us debug this:
context-{4:4}
2 locks held by syz-executor.0/5478:
 #0: ffff88806cd22468 (&local->sockets.lock){++++}-{2:2}, at: nfc_llcp_socket_release+0x56/0xb90 net/nfc/llcp_core.c:90
 #1: ffff88806cd5c0b0 (slock-AF_NFC){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #1: ffff88806cd5c0b0 (slock-AF_NFC){+.+.}-{2:2}, at: nfc_llcp_socket_release+0xcb/0xb90 net/nfc/llcp_core.c:95
stack backtrace:
CPU: 0 PID: 5478 Comm: syz-executor.0 Tainted: G        W          6.7.0-rc2-syzkaller-00198-g7ac1c88a5daa #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 print_lock_invalid_wait_context kernel/locking/lockdep.c:4750 [inline]
 check_wait_context kernel/locking/lockdep.c:4820 [inline]
 __lock_acquire+0x1825/0x7f70 kernel/locking/lockdep.c:5086
 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x136/0xd60 kernel/locking/mutex.c:747
 nfc_llcp_sock_close net/nfc/llcp_core.c:33 [inline]
 nfc_llcp_socket_release+0x498/0xb90 net/nfc/llcp_core.c:120
 local_cleanup+0x28/0xe0 net/nfc/llcp_core.c:161
 nfc_llcp_unregister_device+0x160/0x240 net/nfc/llcp_core.c:1655
 nfc_unregister_device+0x167/0x2a0 net/nfc/core.c:1179
 virtual_ncidev_close+0x59/0x90 drivers/nfc/virtual_ncidev.c:163
 __fput+0x3cc/0xa10 fs/file_table.c:394
 __do_sys_close fs/open.c:1590 [inline]
 __se_sys_close+0x15f/0x220 fs/open.c:1575
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7fe8ddc7b9da
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 03 7f 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 63 7f 02 00 8b 44 24
RSP: 002b:00007fffdaf3d080 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fe8ddc7b9da
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fe8ddd9d980 R08: 0000001b2e060000 R09: 00007fffdaf810b0
R10: 00007fffdaf81080 R11: 0000000000000293 R12: 00000000000151df
R13: ffffffffffffffff R14: 00007fe8dd800000 R15: 0000000000014e9e
 </TASK>


Tested on:

commit:         7ac1c88a lock
git tree:       https://github.com/siddhpant/linux.git lock
console output: https://syzkaller.appspot.com/x/log.txt?x=11f333af680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1e6a76f6c7029ca2
dashboard link: https://syzkaller.appspot.com/bug?extid=bbe84a4010eeea00982d
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.