Re: [OOPS] -git8,9: NULL pointer dereference in mptspi_dv_renegotiate_work

Andrew Morton
2006-09-29T00:27:06Z

On Thu, 28 Sep 2006 15:54:26 -0700
Bryce Harrington <bryce@osdl.org> wrote:

> On Thu, Sep 28, 2006 at 02:51:21PM -0700, Andrew Morton wrote:
> > On Thu, 28 Sep 2006 13:25:48 -0700
> > Bryce Harrington <bryce@osdl.org> wrote:
> >
> > > Apologies if this has already been reported;
> >
> > It has not.
> >
> > > I didn't spot it on the
> > > list. We've noticed an Oops on AMD64 when running linux-2.6.18-git8 and
> > > -git9, but not -git7:
> > >
> > > mptbase: Initiating ioc0 recovery
> > > Unable to handle kernel NULL pointer dereference at 0000000000000500 RIP:
> > > [<ffffffff80489aa2>] mptspi_dv_renegotiate_work+0xc/0x45
> > > PGD 0
> > > Oops: 0000 [1] PREEMPT SMP
> >
>
> > That's very clever.
> >
> > I'd be suspecting a miscompile, or something horrid in kfree().
> >
> > Does it change anything if you move that kfree() down a bit?
> >
>
> Got essentially the same oops, although the addresses have changed a
> little:
>
> mptbase: Initiating ioc0 recovery
> Unable to handle kernel NULL pointer dereference at 0000000000000500 RIP:
> [<ffffffff80489aa3>] mptspi_dv_renegotiate_work+0xd/0x4c
> PGD 0
> Oops: 0000 [1] PREEMPT SMP
> CPU 0
> Modules linked in:
> Pid: 8, comm: events/0 Not tainted 2.6.18-git10 #1
> RIP: 0010:[<ffffffff80489aa3>] [<ffffffff80489aa3>] mptspi_dv_renegotiate_work+0xd/0x4c
> RSP: 0000:ffff81003ec65e40 EFLAGS: 00010246
> RAX: ffff81003ec65ef8 RBX: ffff81003eff6640 RCX: ffff81003ec65ef8
> RDX: ffff81003ed0cf58 RSI: 0000000000000000 RDI: ffff81003eff6640
> RBP: 0000000000000500 R08: ffff81003ec64000 R09: 00000000ffffffff
> R10: 00000000ffffffff R11: ffff81003ed0cf40 R12: ffff81003eff6640
> R13: 0000000000000213 R14: ffff81003eff6640 R15: ffffffff80489a96
> FS: 0000000000000000(0000) GS:ffffffff8077a000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> CR2: 0000000000000500 CR3: 0000000000201000 CR4: 00000000000006e0
> Process events/0 (pid: 8, threadinfo ffff81003ec64000, task ffff81007f180740)
> Stack: ffff81003eff6640 ffff81003eff6648 ffff81003ed0cf40 ffffffff8023f1bd
> ffff81003ed0cf40 ffff81003ed0cf40 ffffffff8023f204 ffff8100016dfd70
> 00000000fffffffc ffffffff8059457d 0000000000000000 ffffffff8023f30
> Call Trace:
> [<ffffffff8023f1bd>] run_workqueue+0x9a/0xe1
> [<ffffffff8023f204>] worker_thread+0x0/0x12e
> [<ffffffff8023f300>] worker_thread+0xfc/0x12e
> [<ffffffff80229f62>] default_wake_function+0x0/0xe
> [<ffffffff80229f62>] default_wake_function+0x0/0xe
> [<ffffffff80242433>] kthread+0xc8/0xf1
> [<ffffffff8020a3f8>] child_rip+0xa/0x12
> [<ffffffff8024236b>] kthread+0x0/0xf1
> [<ffffffff8020a3ee>] child_rip+0x0/0x12
>
>
> Code: 48 8b 45 00 48 8b b8 50 01 00 00 e8 5d 4d fe ff 48 85 c0 48
> RIP [<ffffffff80489aa3>] mptspi_dv_renegotiate_work+0xd/0x4c
> RSP <ffff81003ec65e40>
> CR2: 0000000000000500
> <6>mptbase: Initiating ioc0 recovery
> mptbase: Initiating ioc0 recovery
> mptbase: Initiating ioc0 recovery
> mptbase: Initiating ioc0 recovery
> mptbase: Initiating ioc0 recovery
> scsi0 : ioc0: LSI53C1030, FwRev=01030600h, Ports=1, MaxQ=255, IRQ=185
> target0:0:0: dma_alloc_coherent for parameters failed
> mptscsih: ioc0: attempting task abort! (sc=ffff81003e840c80)
> scsi 0:0:0:0:
> command: cdb[0]=0x12: 12 00 00 00 24 00
> mptbase: Initiating ioc0 recovery
>

Ah. Maybe we're simply being passed a junk pointer. This, please:

--- a/drivers/message/fusion/mptspi.c~a
+++ a/drivers/message/fusion/mptspi.c
@@ -804,6 +804,9 @@ mptspi_dv_renegotiate(struct _MPT_SCSI_H
if (!wqw)
return;

+ printk("%p\n", hd);
+ if ((unsigned long)hd < 4000UL)
+ dump_stack();
INIT_WORK(&wqw->work, mptspi_dv_renegotiate_work, wqw);
wqw->hd = hd;

_