Re: [syzbot] BUG: unable to handle kernel NULL pointer dereference in nci_cmd_timer

[Lin Ma]

> From: syzbot <syzbot+10257d01dd285b15170a@xxxxxxxxxxxxxxxxxxxxxxxxx>
> Sent Time: 2022-11-16 18:52:37 (Wednesday)
> To: davem@xxxxxxxxxxxxx, edumazet@xxxxxxxxxx, krzysztof.kozlowski@xxxxxxxxxx, kuba@xxxxxxxxxx, linma@xxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, netdev@xxxxxxxxxxxxxxx, pabeni@xxxxxxxxxx, syzkaller-bugs@xxxxxxxxxxxxxxxx
> Cc: 
> Subject: [syzbot] BUG: unable to handle kernel NULL pointer dereference in nci_cmd_timer
> 
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    9500fc6e9e60 Merge branch 'for-next/core' into for-kernelci
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> console output: https://syzkaller.appspot.com/x/log.txt?x=16cbf7a5880000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=b25c9f218686dd5e
> dashboard link: https://syzkaller.appspot.com/bug?extid=10257d01dd285b15170a
> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> userspace arch: arm64
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1354dce9880000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10880a95880000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/1363e60652f7/disk-9500fc6e.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/fcc4da811bb6/vmlinux-9500fc6e.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/0b554298f1fa/Image-9500fc6e.gz.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+10257d01dd285b15170a@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> Mem abort info:
>   ESR = 0x0000000096000004
>   EC = 0x25: DABT (current EL), IL = 32 bits
>   SET = 0, FnV = 0
>   EA = 0, S1PTW = 0
>   FSC = 0x04: level 0 translation fault
> Data abort info:
>   ISV = 0, ISS = 0x00000004
>   CM = 0, WnR = 0
> user pgtable: 4k pages, 48-bit VAs, pgdp=000000010c75b000
> [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
> Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.0-rc5-syzkaller-32269-g9500fc6e9e60 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022
> pstate: 004000c5 (nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : __queue_work+0x3c4/0x8b4
> lr : __queue_work+0x3c4/0x8b4 kernel/workqueue.c:1458
> sp : ffff800008003d60
> x29: ffff800008003d60 x28: 0000000000000000 x27: ffff80000d3a9000
> x26: ffff80000d3ad050 x25: ffff80000d2fe008 x24: ffff80000db54000
> x23: 0000000000000000 x22: 0000000000000023 x21: ffff0000c7a95400
> x20: 0000000000000008 x19: ffff0000cd0d20f8 x18: ffff80000db78158
> x17: ffff80000ddda198 x16: ffff80000dc18158 x15: ffff80000d3cbc80
> x14: 0000000000000000 x13: 00000000ffffffff x12: ffff80000d3cbc80
> x11: ff8080000c07dfe4 x10: 0000000000000000 x9 : ffff80000c07dfe4
> x8 : ffff80000d3cbc80 x7 : ffff80000813bae8 x6 : 0000000000000000
> x5 : 0000000000000080 x4 : 0000000000000000 x3 : 0000000000000002
> x2 : 0000000000000008 x1 : 0000000000000000 x0 : ffff0000c0014c00
> Call trace:
>  __queue_work+0x3c4/0x8b4 kernel/workqueue.c:1458
>  queue_work_on+0xb0/0x15c kernel/workqueue.c:1545
>  queue_work include/linux/workqueue.h:503 [inline]
>  nci_cmd_timer+0x30/0x40 net/nfc/nci/core.c:615
>  call_timer_fn+0x90/0x144 kernel/time/timer.c:1474
>  expire_timers kernel/time/timer.c:1519 [inline]
>  __run_timers+0x280/0x374 kernel/time/timer.c:1790
>  run_timer_softirq+0x34/0x5c kernel/time/timer.c:1803
>  _stext+0x168/0x37c
>  ____do_softirq+0x14/0x20 arch/arm64/kernel/irq.c:79
>  call_on_irq_stack+0x2c/0x54 arch/arm64/kernel/entry.S:892
>  do_softirq_own_stack+0x20/0x2c arch/arm64/kernel/irq.c:84
>  invoke_softirq+0x70/0xbc kernel/softirq.c:452
>  __irq_exit_rcu+0xf0/0x140 kernel/softirq.c:650
>  irq_exit_rcu+0x10/0x40 kernel/softirq.c:662
>  __el1_irq arch/arm64/kernel/entry-common.c:472 [inline]
>  el1_interrupt+0x38/0x68 arch/arm64/kernel/entry-common.c:486
>  el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
>  el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:580
>  arch_local_irq_enable+0xc/0x18 arch/arm64/include/asm/irqflags.h:35
>  default_idle_call+0x48/0xb8 kernel/sched/idle.c:109
>  cpuidle_idle_call kernel/sched/idle.c:191 [inline]
>  do_idle+0x110/0x2d4 kernel/sched/idle.c:303
>  cpu_startup_entry+0x24/0x28 kernel/sched/idle.c:400
>  kernel_init+0x0/0x290 init/main.c:729
>  start_kernel+0x0/0x620 init/main.c:890
>  start_kernel+0x450/0x620 init/main.c:1145
>  __primary_switched+0xb4/0xbc arch/arm64/kernel/head.S:471
> Code: 94001384 aa0003f7 aa1303e0 9400144a (f94002f8) 
> ---[ end trace 0000000000000000 ]---
> ----------------
> Code disassembly (best guess):
>    0:	94001384 	bl	0x4e10
>    4:	aa0003f7 	mov	x23, x0
>    8:	aa1303e0 	mov	x0, x19
>    c:	9400144a 	bl	0x5134
> * 10:	f94002f8 	ldr	x24, [x23] <-- trapping instruction
> 
> 
> ---
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> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx.
> 
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> syzbot can test patches for this issue, for details see:
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#syz test: https://github.com/f0rm2l1n/linux-fix.git master