linux-kernel - Re: [syzbot] [input?] KASAN: null-ptr-deref Read in input

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Message-ID: <677bba0b.050a0220.a40f5.000c.GAE@google.com>
Date: Mon, 06 Jan 2025 03:10:03 -0800
From: syzbot <syzbot+fddd3aa6dfcfe50c760d@...kaller.appspotmail.com>
To: hdanton@...a.com, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [input?] KASAN: null-ptr-deref Read in input_event

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: null-ptr-deref Read in input_event

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: null-ptr-deref in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: null-ptr-deref in is_event_supported drivers/input/input.c:67 [inline]
BUG: KASAN: null-ptr-deref in input_event+0x42/0xa0 drivers/input/input.c:395
Read of size 8 at addr 0000000000000030 by task swapper/0/0

CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc4-syzkaller-00080-gf1a2241778d9-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 kasan_report+0xd9/0x110 mm/kasan/report.c:602
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 is_event_supported drivers/input/input.c:67 [inline]
 input_event+0x42/0xa0 drivers/input/input.c:395
 input_report_key include/linux/input.h:439 [inline]
 key_down drivers/hid/hid-appleir.c:159 [inline]
 appleir_raw_event+0x3e5/0x5e0 drivers/hid/hid-appleir.c:232
 __hid_input_report.constprop.0+0x312/0x440 drivers/hid/hid-core.c:2111
 hid_ctrl+0x49f/0x550 drivers/hid/usbhid/hid-core.c:484
 __usb_hcd_giveback_urb+0x389/0x6e0 drivers/usb/core/hcd.c:1650
 usb_hcd_giveback_urb+0x396/0x450 drivers/usb/core/hcd.c:1734
 dummy_timer+0x17f7/0x3960 drivers/usb/gadget/udc/dummy_hcd.c:1993
 __run_hrtimer kernel/time/hrtimer.c:1739 [inline]
 __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1803
 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1820
 handle_softirqs+0x206/0x8d0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xfa/0x160 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:finish_task_switch.isra.0+0x1e5/0xa40 kernel/sched/core.c:5243
Code: 0f 85 ad 07 00 00 8b 0d 9d ce 28 09 85 c9 0f 85 cb 02 00 00 48 89 df e8 f9 f1 c5 05 e8 44 ae 35 00 fb 65 48 8b 1d ab 69 d6 7e <48> 8d bb 30 15 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffffffff88c07c80 EFLAGS: 00000206
RAX: 00000000000d375f RBX: ffffffff88c2c780 RCX: 1ffffffff14abb89
RDX: 0000000000000000 RSI: ffffffff8727fee0 RDI: ffffffff874735a0
RBP: ffffffff88c07cc8 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8a561557 R11: 0000000000000000 R12: ffff8881f583d318
R13: ffff888101f357c0 R14: 0000000000000000 R15: ffff8881f583d318
 context_switch kernel/sched/core.c:5372 [inline]
 __schedule+0x1034/0x34b0 kernel/sched/core.c:6756
 schedule_idle+0x5c/0x90 kernel/sched/core.c:6874
 do_idle+0x284/0x3f0 kernel/sched/idle.c:353
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423
 rest_init+0x16b/0x2b0 init/main.c:747
 start_kernel+0x3df/0x4c0 init/main.c:1102
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
 x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
 common_startup_64+0x12c/0x138
 </TASK>
==================================================================
----------------
Code disassembly (best guess):
   0:	0f 85 ad 07 00 00    	jne    0x7b3
   6:	8b 0d 9d ce 28 09    	mov    0x928ce9d(%rip),%ecx        # 0x928cea9
   c:	85 c9                	test   %ecx,%ecx
   e:	0f 85 cb 02 00 00    	jne    0x2df
  14:	48 89 df             	mov    %rbx,%rdi
  17:	e8 f9 f1 c5 05       	call   0x5c5f215
  1c:	e8 44 ae 35 00       	call   0x35ae65
  21:	fb                   	sti
  22:	65 48 8b 1d ab 69 d6 	mov    %gs:0x7ed669ab(%rip),%rbx        # 0x7ed669d5
  29:	7e
* 2a:	48 8d bb 30 15 00 00 	lea    0x1530(%rbx),%rdi <-- trapping instruction
  31:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  38:	fc ff df
  3b:	48 89 fa             	mov    %rdi,%rdx
  3e:	48                   	rex.W
  3f:	c1                   	.byte 0xc1


Tested on:

commit:         f1a22417 usb: typec: ucsi: Implement ChromeOS UCSI dri..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=12ab3418580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e27867f71e8bc406
dashboard link: https://syzkaller.appspot.com/bug?extid=fddd3aa6dfcfe50c760d
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11b33418580000