Re: [syzbot] [bpf?] [net?] KASAN: slab-use-after-free Read in bq_xmit_all

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in __cpu_map_flush

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 6414 Comm: syz.0.248 Not tainted 6.10.0-syzkaller-11185-g2c9b3512402e-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:__cpu_map_flush+0x42/0xd0
Code: e8 93 d9 d6 ff 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 bd ce 39 00 49 8b 1e 4c 39 f3 74 77 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 9f ce 39 00 4c 8b 23 48 8d 7b c0
RSP: 0018:ffffc90000a18b10 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88806b371e00
RDX: 0000000080000100 RSI: 0000000000000010 RDI: ffffc9000319f800
RBP: dffffc0000000000 R08: ffffffff895fbdfa R09: 1ffffffff1f5d135
R10: dffffc0000000000 R11: fffffbfff1f5d136 R12: ffffc9000319f800
R13: ffffc9000319f820 R14: ffffc9000319f800 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3b96706030 CR3: 0000000025528000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 xdp_do_check_flushed+0x136/0x240 net/core/filter.c:4304
 __napi_poll+0xe4/0x490 net/core/dev.c:6774
 napi_poll net/core/dev.c:6840 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:6962
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5763
Code: 2b 00 74 08 4c 89 f7 e8 1a cb 86 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc9000319f8c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000633f24 RCX: a82dc8c22c65f400
RDX: dffffc0000000000 RSI: ffffffff8bcadea0 RDI: ffffffff8c1f9a00
RBP: ffffc9000319fa08 R08: ffffffff92fd0607 R09: 1ffffffff25fa0c0
R10: dffffc0000000000 R11: fffffbfff25fa0c1 R12: 1ffff92000633f20
R13: dffffc0000000000 R14: ffffc9000319f920 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:327 [inline]
 rcu_read_lock include/linux/rcupdate.h:839 [inline]
 get_mem_cgroup_from_objcg+0x36/0x150 include/linux/memcontrol.h:533
 obj_cgroup_uncharge_pages mm/memcontrol.c:3392 [inline]
 __memcg_kmem_uncharge_page+0xf5/0x310 mm/memcontrol.c:3468
 memcg_kmem_uncharge_page include/linux/memcontrol.h:1818 [inline]
 exit_task_stack_account+0xd7/0x340 kernel/fork.c:564
 do_exit+0x1d02/0x27f0 kernel/exit.c:918
 do_group_exit+0x207/0x2c0 kernel/exit.c:1026
 get_signal+0x16a1/0x1740 kernel/signal.c:2917
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3b96575b59
Code: Unable to access opcode bytes at 0x7f3b96575b2f.
RSP: 002b:00007f3b973cb0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f3b96705f68 RCX: 00007f3b96575b59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f3b96705f68
RBP: 00007f3b96705f60 R08: 00007f3b973cb6c0 R09: 00007f3b973cb6c0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3b96705f6c
R13: 000000000000000b R14: 00007ffd55a3d740 R15: 00007ffd55a3d828
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__cpu_map_flush+0x42/0xd0
Code: e8 93 d9 d6 ff 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 bd ce 39 00 49 8b 1e 4c 39 f3 74 77 48 89 d8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 df e8 9f ce 39 00 4c 8b 23 48 8d 7b c0
RSP: 0018:ffffc90000a18b10 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88806b371e00
RDX: 0000000080000100 RSI: 0000000000000010 RDI: ffffc9000319f800
RBP: dffffc0000000000 R08: ffffffff895fbdfa R09: 1ffffffff1f5d135
R10: dffffc0000000000 R11: fffffbfff1f5d136 R12: ffffc9000319f800
R13: ffffc9000319f820 R14: ffffc9000319f800 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3b96706030 CR3: 000000000e134000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	e8 93 d9 d6 ff       	call   0xffd6d998
   5:	4c 89 f0             	mov    %r14,%rax
   8:	48 c1 e8 03          	shr    $0x3,%rax
   c:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1)
  11:	74 08                	je     0x1b
  13:	4c 89 f7             	mov    %r14,%rdi
  16:	e8 bd ce 39 00       	call   0x39ced8
  1b:	49 8b 1e             	mov    (%r14),%rbx
  1e:	4c 39 f3             	cmp    %r14,%rbx
  21:	74 77                	je     0x9a
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 9f ce 39 00       	call   0x39ced8
  39:	4c 8b 23             	mov    (%rbx),%r12
  3c:	48 8d 7b c0          	lea    -0x40(%rbx),%rdi


Tested on:

commit:         2c9b3512 Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=103762e6980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f4925140c45a2a50
dashboard link: https://syzkaller.appspot.com/bug?extid=707d98c8649695eaf329
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=123c8cad980000