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    SubjectRe: [PATCH -tip][SCSI] scsi: scsi_transport_iscsi.c initialize the variable before it get used
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    On Tue, 2009-05-26 at 16:06 +0000, James Bottomley wrote:
    > On Tue, 2009-05-26 at 21:30 +0530, Jaswinder Singh Rajput wrote:
    > > Hello James,
    > >
    > > On Tue, 2009-05-26 at 10:28 -0500, James Bottomley wrote:
    > > > On Tue, 2009-05-26 at 20:49 +0530, Jaswinder Singh Rajput wrote:
    > > > > I am watching this problem from long time in -tip.
    > > > >
    > > > > Subject: [PATCH] scsi: scsi_transport_iscsi.c initialize the variable before it get used
    > > > >
    > > > > In some cases, err will be used uninitialized.
    > > >
    > > > What cases? A simple theoretical analysis shows that this variable is
    > > > always set.
    > > >
    > >
    > > Ok lets takes your tree:
    > >
    > > http://git.kernel.org/?p=linux/kernel/git/jejb/scsi-misc-2.6.git;a=blob;f=drivers/scsi/scsi_transport_iscsi.c;hb=10eb0f013c63c71c82ede77945a5f390c10cfda6
    > >
    > >
    > > 672 int iscsi_add_session(struct iscsi_cls_session *session, unsigned int target_id)
    > > 673 {
    > > 674 struct Scsi_Host *shost = iscsi_session_to_shost(session);
    > > 675 struct iscsi_cls_host *ihost;
    > > 676 unsigned long flags;
    > > 677 unsigned int id = target_id;
    > > 678 int err;
    > > 679
    > > 680 ihost = shost->shost_data;
    > > 681 session->sid = atomic_add_return(1, &iscsi_session_nr);
    > > 682
    > > 683 if (id == ISCSI_MAX_TARGET) {
    > > 684 for (id = 0; id < ISCSI_MAX_TARGET; id++) {
    > > 685 err = device_for_each_child(&shost->shost_gendev, &id,
    > > 686 iscsi_get_next_target_id);
    > > 687 if (!err)
    > > 688 break;
    > > 689 }
    > > 690
    > > 691 if (id == ISCSI_MAX_TARGET) {
    > > 692 iscsi_cls_session_printk(KERN_ERR, session,
    > > 693 "Too many iscsi targets. Max "
    > > 694 "number of targets is %d.\n",
    > > 695 ISCSI_MAX_TARGET - 1);
    > > 696 goto release_host;
    > > 697 }
    > > 698 }
    > > 699 session->target_id = id;
    > > 700
    > > 701 dev_set_name(&session->dev, "session%u", session->sid);
    > > 702 err = device_add(&session->dev);
    > > 703 if (err) {
    > > 704 iscsi_cls_session_printk(KERN_ERR, session,
    > > 705 "could not register session's dev\n");
    > > 706 goto release_host;
    > > 707 }
    > > 708 transport_register_device(&session->dev);
    > > 709
    > > 710 spin_lock_irqsave(&sesslock, flags);
    > > 711 list_add(&session->sess_list, &sesslist);
    > > 712 spin_unlock_irqrestore(&sesslock, flags);
    > > 713
    > > 714 iscsi_session_event(session, ISCSI_KEVENT_CREATE_SESSION);
    > > 715 return 0;
    > > 716
    > > 717 release_host:
    > > 718 scsi_host_put(shost);
    > > 719 return err;
    > > 720 }
    > >
    > > You are right but compiler is confused and giving warning like this :
    > >
    > > 1. do not go inside :
    > > 684 for (id = 0; id < ISCSI_MAX_TARGET; id++) {
    >
    > How? id is an unsigned int and ISCSI_MAX_TARGET is defined to be -1 in
    > include/scsi/scsi_transport_iscsi.h (might be better if it were
    > UINT_MAX, but -1 is just as good).
    >

    Yes, you are right, I was telling you how compiler was confused in 4.3.2
    but I am glad to hear that this problem is fixed in 4.3.3 as you told
    me :-)

    So now its upto you. 4.3.2 is not soo old, So either initialize the
    variable or stay with stray warning in the kernel ;-)

    Thanks,
    --
    JSR



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