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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Alan Stern" <stern@rowland.harvard.edu>,
	"SF Markus Elfring" <elfring@users.sourceforge.net>,
	"USB list" <linux-usb@vger.kernel.org>,
	"Joe Perches" <joe@perches.com>,
	"Daniel Drake" <drake@endlessm.com>,
	"Dmitry Fleytman" <dmitry@daynix.com>,
	"Eugene Korenevsky" <ekorenevsky@gmail.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Günter Röck" <linux@roeck-us.net>,
	"Johan Hovold" <johan@kernel.org>,
	"Mathias Nyman" <mathias.nyman@linux.intel.com>,
	"Peter Chen" <peter.chen@nxp.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"kernel-janitors@vger.kernel.org"
	<kernel-janitors@vger.kernel.org>
Subject: USB: hub: Delete an error message for a failed memory allocation in usb_hub_clear_tt_buffer()
Date: Thu, 7 Dec 2017 11:35:42 +0300	[thread overview]
Message-ID: <20171207083542.gohu4z3v4fp7gvsu@mwanda> (raw)

On Thu, Dec 07, 2017 at 08:40:07AM +0100, Geert Uytterhoeven wrote:
> Hi Alan,
> 
> On Wed, Dec 6, 2017 at 11:02 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
> > On Wed, 6 Dec 2017, SF Markus Elfring wrote:
> >> >>> Does the existing memory allocation error message include the
> >> >>> &udev->dev device name and driver name?  If it doesn't, there will be
> >> >>> no way for the user to tell that the error message is related to the
> >> >>> device failure.
> >> >>
> >> >> No, but the effect is similar.
> >> >>
> >> >> OOM does a dump_stack() so this function's call tree is shown.
> >> >
> >> > A call stack doesn't tell you which device was being handled.
> >>
> >> Do you find a default Linux allocation failure report insufficient then?
> >>
> >> Would you like to to achieve that the requested information can be determined
> >> from a backtrace?
> >
> > It is not practical to do this.  The memory allocation routines do not
> > for what purpose the memory is being allocated; hence when a failure
> > occurs they cannot tell what device (or other part of the system) will
> > be affected.
> 
> If even allocation of 24 bytes fails, lots of other devices and other parts of
> the system will start failing really soon...
> 

Small allocations never fail in the current kernel.

regards,
dan carpenter
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             reply	other threads:[~2017-12-07  8:35 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-07  8:35 Dan Carpenter [this message]
  -- strict thread matches above, loose matches on Subject: below --
2017-12-08 17:42 USB: hub: Delete an error message for a failed memory allocation in usb_hub_clear_tt_buffer() Alan Stern
2017-12-08 12:00 SF Markus Elfring
2017-12-08 11:11 Dan Carpenter
2017-12-08  7:43 Geert Uytterhoeven
2017-12-07 21:26 Alan Stern
2017-12-07 20:51 Dan Carpenter
2017-12-07 16:20 Joe Perches
2017-12-07 15:12 Alan Stern
2017-12-07 13:38 SF Markus Elfring
2017-12-07  9:30 Dan Carpenter
2017-12-07  9:17 Oliver Neukum
2017-12-07  8:56 Greg Kroah-Hartman
2017-12-07  8:45 Geert Uytterhoeven
2017-12-07  7:40 Geert Uytterhoeven
2017-12-06 22:02 Alan Stern
2017-12-06 21:33 SF Markus Elfring
2017-12-06 21:18 Alan Stern
2017-12-06 20:20 Geert Uytterhoeven
2017-12-06 20:05 Joe Perches
2017-12-06 17:51 SF Markus Elfring
2017-12-06 17:27 Geert Uytterhoeven
2017-12-06 16:57 Greg Kroah-Hartman
2017-12-06 16:45 Alan Stern
2017-12-06 16:13 SF Markus Elfring

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