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From: Yonghong Song <yonghong.song@linux.dev>
To: Zac Ecob <zacecob@protonmail.com>,
	"bpf@vger.kernel.org" <bpf@vger.kernel.org>
Subject: Re: Kernel oops caused by signed divide
Date: Mon, 9 Sep 2024 10:27:42 -0700	[thread overview]
Message-ID: <7856b29c-4db3-46bf-a679-5e63fc08a353@linux.dev> (raw)
In-Reply-To: <tPJLTEh7S_DxFEqAI2Ji5MBSoZVg7_G-Py2iaZpAaWtM961fFTWtsnlzwvTbzBzaUzwQAoNATXKUlt0LZOFgnDcIyKCswAnAGdUF3LBrhGQ=@protonmail.com>


On 9/9/24 10:21 AM, Zac Ecob wrote:
> Hello,
>
> I recently received a kernel 'oops' about a divide error.
> After some research, it seems that the 'div64_s64' function used for the 'MOD'/'REM' instructions boils down to an 'idiv'.
>
> The 'dividend' is set to INT64_MIN, and the 'divisor' to -1, then because of two's complement, there is no corresponding positive value, causing the error (at least to my understanding).

Could you provide a reproducible test case for this? It will make it easy to debug the issue.


  reply	other threads:[~2024-09-09 17:27 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-09 17:21 Kernel oops caused by signed divide Zac Ecob
2024-09-09 17:27 ` Yonghong Song [this message]
2024-09-09 17:29 ` Alexei Starovoitov
2024-09-09 23:47   ` Yonghong Song
2024-09-10 14:21   ` Yonghong Song
2024-09-10 14:44     ` Dave Thaler
2024-09-10 15:18       ` Yonghong Song
2024-09-10 15:21         ` Alexei Starovoitov
2024-09-10 18:12           ` Yonghong Song
2024-09-10 15:21     ` Alexei Starovoitov
2024-09-10 18:02       ` Yonghong Song
2024-09-10 18:25         ` Alexei Starovoitov
2024-09-10 19:32           ` Yonghong Song
2024-09-10 21:53             ` Alexei Starovoitov
2024-09-10 22:00               ` Yonghong Song
2024-09-10 22:43               ` Andrii Nakryiko

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