Messages in this thread | | | Date | Fri, 11 Nov 2022 12:23:51 -0500 | Subject | Re: [PATCH] scsi: scsi_debug: Fix a warning in resp_write_scat() | From | Douglas Gilbert <> |
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On 2022-11-11 05:05, Harshit Mogalapalli wrote: > As 'lbdof_blen' is coming from user, if the size in kzalloc() > is >= MAX_ORDER then we hit a warning. > > Call trace: > > sg_ioctl > sg_ioctl_common > scsi_ioctl > sg_scsi_ioctl > blk_execute_rq > blk_mq_sched_insert_request > blk_mq_run_hw_queue > __blk_mq_delay_run_hw_queue > __blk_mq_run_hw_queue > blk_mq_sched_dispatch_requests > __blk_mq_sched_dispatch_requests > blk_mq_dispatch_rq_list > scsi_queue_rq > scsi_dispatch_cmd > scsi_debug_queuecommand > schedule_resp > resp_write_scat > > If you try to allocate a memory larger than(>=) MAX_ORDER, then kmalloc() > will definitely fail. It creates a stack trace and messes up dmesg. > The user controls the size here so if they specify a too large size it > will fail. > > Add __GFP_NOWARN in order to avoid too large allocation warning. > This is detected by static analysis using smatch. > > Fixes: 481b5e5c7949 ("scsi: scsi_debug: add resp_write_scat function") > Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Thanks.
> --- > drivers/scsi/scsi_debug.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c > index 697fc57bc711..273224d29ce9 100644 > --- a/drivers/scsi/scsi_debug.c > +++ b/drivers/scsi/scsi_debug.c > @@ -3778,7 +3778,7 @@ static int resp_write_scat(struct scsi_cmnd *scp, > mk_sense_buffer(scp, ILLEGAL_REQUEST, INVALID_FIELD_IN_CDB, 0); > return illegal_condition_result; > } > - lrdp = kzalloc(lbdof_blen, GFP_ATOMIC); > + lrdp = kzalloc(lbdof_blen, GFP_ATOMIC | __GFP_NOWARN); > if (lrdp == NULL) > return SCSI_MLQUEUE_HOST_BUSY; > if (sdebug_verbose)
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