On Thu, 2008-09-11 at 15:35 -0700, Andrey Yurovsky wrote:
> Hi Dan. With this patch, I get a NULL pointer dereference if I pull
> the card while scanning:
So the USB disconnect calls lbs_remove_card(), which first calls
lbtf_free_adapter() (clearing the entire command array), and then it
calls ieee80211_unregister_hw(), which calls lbs_op_stop(), which clears
the current command node, and then ieee80211_unregister_hw() calls
flush_workqueue() on the work queue that the scan could currently be
pending in.
The scan command, currently blocking in __lbtf_cmd() in
wait_event_interruptible(), now gets woken up because of my patch to
lbs_op_stop(). Its flow continues through __lbtf_cmd() until
__lbtf_cleanup_and_insert_cmd(), where it tries a
memset(cmdnode->cmdbuf, 0, ...). Unfortunately, cmdnode->cmdbuf is now
NULL, having been cleared in lbtf_free_cmd_buffer() already by
lbtf_free_adapter() quite early in the device removal chain. Explosion.
About all I can think of right now is something like:
diff --git a/drivers/net/wireless/libertas_tf/cmd.c b/drivers/net/wireless/libertas_tf/cmd.c
index fdbcf8b..481d189 100644
--- a/drivers/net/wireless/libertas_tf/cmd.c
+++ b/drivers/net/wireless/libertas_tf/cmd.c
@@ -550,11 +550,16 @@ int __lbtf_cmd(struct lbtf_private *priv, uint16_t command,
might_sleep();
ret = wait_event_interruptible(cmdnode->cmdwait_q,
cmdnode->cmdwaitqwoken);
- if (ret) {
+ if (ret) {
printk(KERN_DEBUG
"libertastf: command 0x%04x interrupted by signal",
command);
return ret;
+ } else if (priv->surpriseremoved) {
+ printk(KERN_DEBUG
+ "libertastf: command 0x%04x interrupted by device "
+ "disconnect", command);
+ return -ENODEV;
}
spin_lock_irqsave(&priv->driver_lock, flags);
Does that fix it for you? If so, I'll roll this one up with the
previous patch and resubmit.
Dan
> 6>[ 131.596162] libertastf: URB in failure status: -71
> <6>[ 131.712016] usb 4-5: USB disconnect, address 5
> <7>[ 131.933390] libertastf: command 0x001d failed: -2
> <1>[ 131.933429] BUG: unable to handle kernel NULL pointer
> dereference at 00000000
> <1>[ 131.933437] IP: [<f8d71d7e>]
> :libertas_tf:__lbtf_cleanup_and_insert_cmd+0x2e/0x60
> <4>[ 131.933452] *pde = 00000000
> <0>[ 131.933511] Oops: 0002 [#1] SMP
> <4>[ 131.933519] Modules linked in: arc4 ecb crypto_blkcipher
> libertas_tf_usb libertas_tf mac80211 cfg80211 binfmt_misc radeon drm
> rfcomm l2cap bluetooth nfsd auth_rpcgss exportfs speedstep_lib
> cpufreq_userspace cpufreq_stats cpufreq_powersave cpufreq_ondemand
> freq_table cpufreq_conservative video output rfkill input_polldev sbs
> sbshc battery nfs lockd nfs_acl sunrpc iptable_filter ip_tables
> x_tables ac ppdev psmouse serio_raw yenta_socket rsrc_nonstatic
> container parport_pc parport pcspkr iTCO_wdt iTCO_vendor_support
> button intel_agp agpgart shpchp pci_hotplug ipv6 evdev ext3 jbd
> mbcache usbhid hid sg sr_mod sd_mod cdrom ata_piix pata_acpi b44
> floppy ata_generic libata scsi_mod dock ssb pcmcia pcmcia_core mii
> ehci_hcd uhci_hcd usbcore thermal processor fan thermal_sys fuse
> <4>[ 131.934926]
> <4>[ 131.934931] Pid: 6090, comm: usb Not tainted (2.6.27-rc6-wl #1)
> <4>[ 131.934963] EIP: 0060:[<f8d71d7e>] EFLAGS: 00010046 CPU: 0
> <4>[ 131.934999] EIP is at __lbtf_cleanup_and_insert_cmd+0x2e/0x60
> [libertas_tf]
> <4>[ 131.935032] EAX: 00000000 EBX: f4f372f0 ECX: 00000200 EDX: f4f372f0
> <4>[ 131.935037] ESI: f751ee60 EDI: 00000000 EBP: f751ee60 ESP: f40efecc
> <4>[ 131.935069] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
> <0>[ 131.935101] Process usb (pid: 6090, ti=f40ee000 task=f7530fc0
> task.ti=f40ee000)
> <0>[ 131.935106] Stack: f751f7d4 fffffffe 00000282 f8d72133 f8d72e88
> 0000001d fffffffe 0000001d
> <0>[ 131.935177] f4f372f0 00000000 f7530fc0 c013c580 f40efefc
> f40efefc f751e1a0 f751fb48
> <0>[ 131.935275] f751f938 f4110480 f8d7225a 00000030 f8d725d0
> f40eff24 00300001 c0102c05
> <0>[ 131.935478] Call Trace:
> <0>[ 131.935509] [<f8d72133>] __lbtf_cmd+0xd3/0x130 [libertas_tf]
> <0>[ 131.935551] [<c013c580>] autoremove_wake_function+0x0/0x40
> <0>[ 131.935589] [<f8d7225a>] lbtf_set_channel+0x3a/0x40 [libertas_tf]
> <0>[ 131.935600] [<f8d725d0>] lbtf_cmd_copyback+0x0/0x50 [libertas_tf]
> <0>[ 131.935637] [<c0102c05>] __switch_to+0xa5/x160
> <0>[ 131.935644] [<c0123e8f>] finish_task_switch+0x1f/0xb0
> <0>[ 131.935652] [<c0324e6b>] schedule+0x25b/0x6a0
> <0>[ 131.935660] [<f8d7176>] lbtf_op_config+0x26/0x0 [libertas_tf]
> <0>[ 11.935750] [<f8d91056> ieee80211_hw_config+056/0x70 [mac80211]
> <0[ 131.935803] [<f8d9e49>] ieee80211_sta_scn_work+0x179/0x1e0 [ma80211]
> <0>[ 131.93585] [<c01397b4>] queue_elayed_work_on+0x84/0x0
> <0>[ 131.935887] [c013909a>] run_workquee+0xca/0x170
> <0>[ 131935949] [<c0326ae1>]_spin_lock_irqsave+0x3/0x50
> <0>[ 131.936036] [<f8d97cd0>] ieee8021_sta_scan_work+0x0/0xe0 [mac80211]
> <0>[ 13.936085] [<c0139980>]worker_thread+0x0/0xe0
> 0>[ 131.936119] [<c139a00>] worker_thread+x80/0xe0
> <0>[ 131.93679] [<c013c580>] autoemove_wake_function+0x/0x40
> <0>[ 131.936239 [<c0139980>] workerthread+0x0/0xe0
> <0>[ 31.936299] [<c013c262] kthread+0x42/0x70
> <0013c20>] kthread+0x0/0x70
> <0[ 131.936392] [<c0100d7>] kernel_thread_heper+0x7/0x10
> <0>[ 131936453] ======================
> <0>[ 131.93509] Code: 85 d2 89 1c24 89 d3 89 74 24 04 8 c6 89 7c 24
> 08 74 33 c 42 0c 00 00 00 00 31 0 b9 00 02 00 00 c7 4210 00 00 00 00
> 8b 7a 1 <f3> ab 8b 96 68 09 0 00 8d 86 64 09 00 00 9 9e 68 09 00 00 89
> <>[ 131.937384] EIP: [f8d71d7e>]
> __lbtf_clenup_and_insert_cmd+0x2/0x60 [libertas_tf] SSESP
> 0068:f40efecc
> <4>[ 131.937384] ---[ endtrace 32fe8679f56e2101]---
>
>
> On Mon, Sep 8, 2008 at 1:34 PM, Dan Williams <dcbw@xxxxxxxxxx> wrote:
> > Ensure that the current command is torn down when cleaning up.
> >
> > Signed-off-by: Dan Williams <dcbw@xxxxxxxxxx>
> > ---
> >
> > Completely untested but based on the libertas patch for the same
> > problem. Luis, can you give it a shot and make sure there aren't any
> > regressions when pulling the card or rmmod-ing the driver?
> >
> > diff --git a/drivers/net/wireless/libertas_tf/main.c b/drivers/net/wireless/libertas_tf/main.c
> > index c948021..5f7bf04 100644
> > --- a/drivers/net/wireless/libertas_tf/main.c
> > +++ b/drivers/net/wireless/libertas_tf/main.c
> > @@ -296,8 +296,8 @@ static void lbtf_op_stop(struct ieee80211_hw *hw)
> > struct lbtf_private *priv = hw->priv;
> > unsigned long flags;
> > struct sk_buff *skb;
> > -
> > struct cmd_ctrl_node *cmdnode;
> > +
> > /* Flush pending command nodes */
> > spin_lock_irqsave(&priv->driver_lock, flags);
> > list_for_each_entry(cmdnode, &priv->cmdpendingq, list) {
> > @@ -306,7 +306,14 @@ static void lbtf_op_stop(struct ieee80211_hw *hw)
> > wake_up_interruptible(&cmdnode->cmdwait_q);
> > }
> >
> > + /* Flush the command the card is currently processing */
> > + if (priv->cur_cmd) {
> > + priv->cur_cmd->result = -ENOENT;
> > + priv->cur_cmd->cmdwaitqwoken = 1;
> > + wake_up_interruptible(&priv->cur_cmd->cmdwait_q);
> > + }
> > spin_unlock_irqrestore(&priv->driver_lock, flags);
> > +
> > cancel_work_sync(&priv->cmd_work);
> > cancel_work_sync(&priv->tx_work);
> > while ((skb = skb_dequeue(&priv->bc_ps_buf)))
> >
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
> > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
