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From: Greg KH <gregkh@linuxfoundation.org>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: axboe@kernel.dk, viro@zeniv.linux.org.uk, bvanassche@acm.org,
	rostedt@goodmis.org, mingo@redhat.com, jack@suse.cz,
	ming.lei@redhat.com, nstange@suse.de, akpm@linux-foundation.org,
	mhocko@suse.com, yukuai3@huawei.com, linux-block@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 5/6] blktrace: break out of blktrace setup on concurrent calls
Date: Fri, 1 May 2020 18:51:45 +0200	[thread overview]
Message-ID: <20200501165145.GA2085362@kroah.com> (raw)
In-Reply-To: <20200501150626.GM11244@42.do-not-panic.com>

On Fri, May 01, 2020 at 03:06:26PM +0000, Luis Chamberlain wrote:
> On Wed, Apr 29, 2020 at 11:49:37AM +0200, Greg KH wrote:
> > On Wed, Apr 29, 2020 at 07:46:26AM +0000, Luis Chamberlain wrote:
> > > diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> > > index 5c52976bd762..383045f67cb8 100644
> > > --- a/kernel/trace/blktrace.c
> > > +++ b/kernel/trace/blktrace.c
> > > @@ -516,6 +518,11 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
> > >  	 */
> > >  	strreplace(buts->name, '/', '_');
> > >  
> > > +	if (q->blk_trace) {
> > > +		pr_warn("Concurrent blktraces are not allowed\n");
> > > +		return -EBUSY;
> > 
> > You have access to a block device here, please use dev_warn() instead
> > here for that, that makes it obvious as to what device a "concurrent
> > blktrace" was attempted for.
> 
> The block device may be empty, one example is for scsi-generic, but I'll
> use buts->name.

That's fine, give us a chance to know what went wrong, your line as is
does not do that :(

thanks,

greg k-h


  parent reply	other threads:[~2020-05-01 16:51 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-29  7:46 [PATCH v3 0/6] block: fix blktrace debugfs use after free Luis Chamberlain
2020-04-29  7:46 ` [PATCH v3 1/6] block: revert back to synchronous request_queue removal Luis Chamberlain
2020-04-29 11:15   ` Christoph Hellwig
2020-05-02  0:22   ` Bart Van Assche
2020-05-03 10:32     ` Matthew Wilcox
2020-05-04 16:18       ` Luis Chamberlain
2020-05-04 16:16     ` Luis Chamberlain
2020-04-29  7:46 ` [PATCH v3 2/6] block: move main block debugfs initialization to its own file Luis Chamberlain
2020-04-29 11:15   ` Christoph Hellwig
2020-04-29  7:46 ` [PATCH v3 3/6] blktrace: move blktrace debugfs creation to helper function Luis Chamberlain
2020-04-29 11:20   ` Christoph Hellwig
2020-05-02  0:25   ` Bart Van Assche
2020-04-29  7:46 ` [PATCH v3 4/6] blktrace: fix debugfs use after free Luis Chamberlain
2020-04-29  9:47   ` Greg KH
2020-04-29 11:26   ` Christoph Hellwig
2020-04-29 11:45     ` Luis Chamberlain
2020-04-29 11:50       ` Christoph Hellwig
2020-04-29 12:02         ` Luis Chamberlain
2020-04-29 12:04           ` Christoph Hellwig
2020-04-29 12:21             ` Luis Chamberlain
2020-04-29 12:57               ` Greg KH
2020-05-01 15:24                 ` Luis Chamberlain
2020-05-07 11:30   ` [blktrace] d106a3fdba: BUG:kernel_NULL_pointer_dereference,address kernel test robot
2020-04-29  7:46 ` [PATCH v3 5/6] blktrace: break out of blktrace setup on concurrent calls Luis Chamberlain
2020-04-29  9:49   ` Greg KH
2020-05-01 15:06     ` Luis Chamberlain
2020-05-01 15:34       ` Christoph Hellwig
2020-05-01 15:40         ` Luis Chamberlain
2020-05-01 15:50           ` Luis Chamberlain
2020-05-01 16:51       ` Greg KH [this message]
2020-04-29  7:46 ` [PATCH v3 6/6] loop: be paranoid on exit and prevent new additions / removals Luis Chamberlain
2020-04-29  9:50   ` Greg KH
2020-05-03  9:09     ` Luis Chamberlain
2020-04-29 14:05   ` Ming Lei

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