Re: [syzbot] [mptcp?] general protection fault in proc_scheduler

Matthieu Baerts
2025-01-04T19:12:08Z

Hi Al, Eric,

On 04/01/2025 20:00, Al Viro wrote:
> On Sat, Jan 04, 2025 at 07:53:22PM +0100, Eric Dumazet wrote:
>
>> I do think this is a bug in process accounting, not in networking.
>>
>> It might make sense to output a record on a regular file, but probably
>> not on any other files.
>>
>> diff --git a/kernel/acct.c b/kernel/acct.c
>> index 179848ad33e978a557ce695a0d6020aa169177c6..a211305cb930f6860d02de7f45ebd260ae03a604
>> 100644
>> --- a/kernel/acct.c
>> +++ b/kernel/acct.c
>> @@ -495,6 +495,9 @@ static void do_acct_process(struct bsd_acct_struct *acct)
>> const struct cred *orig_cred;
>> struct file *file = acct->file;
>>
>> + if (S_ISREG(file_inode(file)->i_mode))
>> + return;
>
> ... won't help, since the file in question *is* a regular file. IOW, it's
> a wrong predicate here.

On my side, it looks like I'm not able to reproduce the issue with this
patch. Without it, it is very easy to reproduce it. (But I don't know if
there are other consequences that would avoid the issue to happen: when
looking at the logs, with the patch, I don't have heaps of "Process
accounting resumed" messages that I had before.)

Cheers,
Matt
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