On 08/25, Dan Carpenter wrote:
> Hello Konrad Zapalowicz,
>
> The patch ea6e9dea2e72: "staging: dgnc: Fix frame size is larger than
> 1024B" from Aug 6, 2014, leads to the following static checker
> warning:
>
> drivers/staging/dgnc/dgnc_tty.c:479 dgnc_sniff_nowait_nolock()
> error: scheduling with locks held: 'spin_lock:ch_lock'
>
> drivers/staging/dgnc/dgnc_tty.c
> 467 void dgnc_sniff_nowait_nolock(struct channel_t *ch, uchar *text, uchar *buf, int len)
> 468 {
> 469 struct timeval tv;
> 470 int n;
> 471 int r;
> 472 int nbuf;
> 473 int i;
> 474 int tmpbuflen;
> 475 char *tmpbuf;
> 476 char *p;
> 477 int too_much_data;
> 478
> 479 tmpbuf = kzalloc(TMPBUFLEN, GFP_KERNEL);
> ^^^^^^^^^^
>
> This is a sleeping under spinlock bug.
>
> 480 if (!tmpbuf)
> 481 return;
> 482 p = tmpbuf;
>
> Normally the way to fix these is to just do a GFP_ATOMIC allocation but
> sometimes you can shuffle the lock and the allocation around to avoid
> the problem.
Thanks for the info, I was not aware about this kind of consequences.
I'll fix it in the upcoming series of patches for the dgnc driver.
By the way, now I understand why someone has put there that local,
huge table which was fixed by my patch.
cheers,
konrad
> regards,
> dan carpenter
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