Re: BUG: using __this_cpu_read() in preemptible code in __bad_area_nosemaphore

[Steven Rostedt]

On Thu, 29 Oct 2020 18:53:17 -0700
syzbot <syzbot+cebc65195a8639f648b9@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

> Hello,
> 
> syzbot found the following issue on:

Didn't Peter already send a fix for this? Is it not upstream yet?

-- Steve

> 
> HEAD commit:    672f8871 Merge tag 'timers-urgent-2020-10-25' of git://git..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14bb0aac500000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=6ab976a648fdc6
> dashboard link: https://syzkaller.appspot.com/bug?extid=cebc65195a8639f648b9
> compiler:       gcc (GCC) 10.1.0-syz 20200507
> userspace arch: i386
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+cebc65195a8639f648b9@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> check_preemption_disabled: 1 callbacks suppressed
> BUG: usqemu-system-x86_64: warning: guest updated active QH
> caller is lockdep_hardirqs_on_prepare+0x5e/0x410 kernel/locking/lockdep.c:4060
> CPU: 0 PID: 9482 Comm: syz-executor.0 Not tainted 5.9.0-syzkaller #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x107/0x163 lib/dump_stack.c:118
>  check_preemption_disabled+0x123/0x130 lib/smp_processor_id.c:48
>  lockdep_hardirqs_on_prepare+0x5e/0x410 kernel/locking/lockdep.c:4060
>  trace_hardirqs_on+0x5b/0x1c0 kernel/trace/trace_preemptirq.c:49
>  __bad_area_nosemaphore+0xc6/0x400 arch/x86/mm/fault.c:797
>  do_user_addr_fault+0x7d7/0xb40 arch/x86/mm/fault.c:1335
>  handle_page_fault arch/x86/mm/fault.c:1429 [inline]
>  exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1485
>  asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:583
> RIP: 0023:0x808bb62
> Code: 00 00 0f bc d1 f3 0f 7f 27 f3 0f 7f 6f 10 f3 0f 7f 77 20 f3 0f 7f 7f 30 83 c3 0f 29 d3 8d 7c 17 31 e9 d2 0b 00 00 66 0f ef c0 <66> 0f 6f 0e 66 0f 74 c1 66 0f d7 d0 83 fb 11 0f 86 e2 01 00 00 85
> RSP: 002b:00000000f5533c90 EFLAGS: 00010246
> RAX: 00000000f5533cb0 RBX: 00000000000003ff RCX: 0000000000000000
> RDX: 000000000002c550 RSI: 0000000000000000 RDI: 00000000f5533cb0
> RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> BUG: using __this_cpu_read() in preemptible [00000000] code: syz-executor.0/9482
> caller is lockdep_hardirqs_on+0x38/0x110 kernel/locking/lockdep.c:4129
> CPU: 0 PID: 9482 Comm: syz-executor.0 Not tainted 5.9.0-syzkaller #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x107/0x163 lib/dump_stack.c:118
>  check_preemption_disabled+0x123/0x130 lib/smp_processor_id.c:48
>  lockdep_hardirqs_on+0x38/0x110 kernel/locking/lockdep.c:4129
>  __bad_area_nosemaphore+0xc6/0x400 arch/x86/mm/fault.c:797
>  do_user_addr_fault+0x7d7/0xb40 arch/x86/mm/fault.c:1335
>  handle_page_fault arch/x86/mm/fault.c:1429 [inline]
>  exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1485
>  asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:583
> RIP: 0023:0x808bb62
> Code: 00 00 0f bc d1 f3 0f 7f 27 f3 0f 7f 6f 10 f3 0f 7f 77 20 f3 0f 7f 7f 30 83 c3 0f 29 d3 8d 7c 17 31 e9 d2 0b 00 00 66 0f ef c0 <66> 0f 6f 0e 66 0f 74 c1 66 0f d7 d0 83 fb 11 0f 86 e2 01 00 00 85
> RSP: 002b:00000000f5533c90 EFLAGS: 00010246
> RAX: 00000000f5533cb0 RBX: 00000000000003ff RCX: 0000000000000000
> RDX: 000000000002c550 RSI: 0000000000000000 RDI: 00000000f5533cb0
> RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> 
> 
> ---
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