[PATCH 39/52] iwlwifi: fix iwl_queue_used bug when read_ptr == write_ptr

From: Greg Kroah-Hartman
Date: Thu Jan 14 2010 - 17:33:00 EST

From: Zhu Yi <yi.zhu@xxxxxxxxx>

commit c8106d7625a58ee4387cb2efe3e82320ad44b467 upstream.

When txq read_ptr equals to write_ptr, iwl_queue_used should
always return false. Because there is no used TFD in this case.

This is a complementary fix to the fix already included in commit "iwl3945:
fix panic in iwl3945 driver". Both fixes are needed to address the panic
below.

This problem was discussed on linux-wireless in
http://thread.gmane.org/gmane.linux.kernel.wireless.general/43568

<1>[ 7290.414172] IP: [<ffffffffa0dd53a1>] iwl3945_rx_reply_tx+0xc1/0x450 [iwl3945]
<4>[ 7290.414205] PGD 0
<1>[ 7290.414214] Thread overran stack, or stack corrupted
<0>[ 7290.414229] Oops: 0002 [#1] PREEMPT SMP
<0>[ 7290.414246] last sysfs file: /sys/devices/platform/coretemp.1/temp1_input
<4>[ 7290.414265] CPU 0
<4>[ 7290.414274] Modules linked in: af_packet nfsd usb_storage usb_libusual cpufreq_powersave exportfs cpufreq_conservative iwl3945 nfs cpufreq_userspace snd_hda_codec_realtek acpi_cpufreq uvcvideo lockd iwlcore snd_hda_intel joydev coretemp nfs_acl videodev snd_hda_codec mac80211 v4l1_compat snd_hwdep sbp2 v4l2_compat_ioctl32 uhci_hcd psmouse auth_rpcgss ohci1394 cfg80211 ehci_hcd video ieee1394 snd_pcm serio_raw battery ac nvidia(P) usbcore output sunrpc evdev lirc_ene0100 snd_page_alloc rfkill tg3 libphy fuse lzo lzo_decompress lzo_compress
<6>[ 7290.414486] Pid: 0, comm: swapper Tainted: P 2.6.32-rc8-wl #213 Aspire 5720
<6>[ 7290.414507] RIP: 0010:[<ffffffffa0dd53a1>] [<ffffffffa0dd53a1>] iwl3945_rx_reply_tx+0xc1/0x450 [iwl3945]
<6>[ 7290.414541] RSP: 0018:ffff880002203d60 EFLAGS: 00010246
<6>[ 7290.414557] RAX: 000000000000004f RBX: ffff880064c11600 RCX: 0000000000000013
<6>[ 7290.414576] RDX: ffffffffa0ddcf20 RSI: ffff8800512b7008 RDI: 0000000000000038
<6>[ 7290.414596] RBP: ffff880002203dd0 R08: 0000000000000000 R09: 0000000000000100
<6>[ 7290.414616] R10: 0000000000000001 R11: 0000000000000000 R12: 00000000000000a0
<6>[ 7290.414635] R13: 0000000000000002 R14: 0000000000000013 R15: 0000000000020201
<6>[ 7290.414655] FS: 0000000000000000(0000) GS:ffff880002200000(0000) knlGS:0000000000000000
<6>[ 7290.414677] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
<6>[ 7290.414693] CR2: 0000000000000041 CR3: 0000000001001000 CR4: 00000000000006f0
<6>[ 7290.414712] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<6>[ 7290.414732] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
<4>[ 7290.414752] Process swapper (pid: 0, threadinfo ffffffff81524000, task ffffffff81528b60)
<0>[ 7290.414772] Stack:
<4>[ 7290.414780] ffff880002203da0 0000000000000046 0000000000000000 0000000000000046
<4>[ 7290.414804] <0> 0000000000000282 0000000000000282 0000000000000282 ffff880064c12010
<4>[ 7290.414830] <0> ffff880002203db0 ffff880064c11600 ffff880064c12e50 ffff8800512b7000
<0>[ 7290.414858] Call Trace:
<0>[ 7290.414867] <IRQ>
<4>[ 7290.414884] [<ffffffffa0dc8c47>] iwl3945_irq_tasklet+0x657/0x1740 [iwl3945]
<4>[ 7290.414910] [<ffffffff8138fc60>] ? _spin_unlock+0x30/0x60
<4>[ 7290.414931] [<ffffffff81049a21>] tasklet_action+0x101/0x110
<4>[ 7290.414950] [<ffffffff8104a3d0>] __do_softirq+0xc0/0x160
<4>[ 7290.414968] [<ffffffff8100d01c>] call_softirq+0x1c/0x30
<4>[ 7290.414986] [<ffffffff8100eff5>] do_softirq+0x75/0xb0
<4>[ 7290.415003] [<ffffffff81049ee5>] irq_exit+0x95/0xa0
<4>[ 7290.415020] [<ffffffff8100e547>] do_IRQ+0x77/0xf0
<4>[ 7290.415038] [<ffffffff8100c7d3>] ret_from_intr+0x0/0xf
<0>[ 7290.415052] <EOI>
<4>[ 7290.415067] [<ffffffff81234efa>] ? acpi_idle_enter_bm+0x270/0x2a5
<4>[ 7290.415087] [<ffffffff81234f04>] ? acpi_idle_enter_bm+0x27a/0x2a5
<4>[ 7290.415107] [<ffffffff81234efa>] ? acpi_idle_enter_bm+0x270/0x2a5
<4>[ 7290.415130] [<ffffffff812c11f3>] ? cpuidle_idle_call+0x93/0xf0
<4>[ 7290.415149] [<ffffffff8100b0d7>] ? cpu_idle+0xa7/0x110
<4>[ 7290.415168] [<ffffffff8137b3d5>] ? rest_init+0x75/0x80
<4>[ 7290.415187] [<ffffffff8158cd0a>] ? start_kernel+0x3a7/0x3b3
<4>[ 7290.415206] [<ffffffff8158c315>] ? x86_64_start_reservations+0x125/0x129
<4>[ 7290.415227] [<ffffffff8158c3fd>] ? x86_64_start_kernel+0xe4/0xeb
<0>[ 7290.415243] Code: 00 41 39 ce 0f 8d e8 01 00 00 48 8b 47 40 48 63 d2 48 69 d2 98 00 00 00 4c 8b 04 02 48 c7 c2 20 cf dd a0 49 8d 78 38 49 8d 40 4f <c6> 47 09 00 c6 47 0c 00 c6 47 0f 00 c6 47 12 00 c6 47 15 00 49
<1>[ 7290.415382] RIP [<ffffffffa0dd53a1>] iwl3945_rx_reply_tx+0xc1/0x450 [iwl3945]
<4>[ 7290.415410] RSP <ffff880002203d60>
<0>[ 7290.415421] CR2: 0000000000000041
<4>[ 7290.415436] ---[ end trace ec46807277caa515 ]---
<0>[ 7290.415450] Kernel panic - not syncing: Fatal exception in interrupt
<4>[ 7290.415468] Pid: 0, comm: swapper Tainted: P D 2.6.32-rc8-wl #213
<4>[ 7290.415486] Call Trace:
<4>[ 7290.415495] <IRQ> [<ffffffff8138c040>] panic+0x7d/0x13a
<4>[ 7290.415519] [<ffffffff8101071a>] oops_end+0xda/0xe0
<4>[ 7290.415538] [<ffffffff8102e1ea>] no_context+0xea/0x250
<4>[ 7290.415557] [<ffffffff81038991>] ? select_task_rq_fair+0x511/0x780
<4>[ 7290.415578] [<ffffffff8102e475>] __bad_area_nosemaphore+0x125/0x1e0
<4>[ 7290.415597] [<ffffffff81038d0c>] ? __enqueue_entity+0x7c/0x80
<4>[ 7290.415616] [<ffffffff81039201>] ? enqueue_task_fair+0x111/0x150
<4>[ 7290.415636] [<ffffffff8102e53e>] bad_area_nosemaphore+0xe/0x10
<4>[ 7290.415656] [<ffffffff8102e8fa>] do_page_fault+0x26a/0x320
<4>[ 7290.415674] [<ffffffff813905df>] page_fault+0x1f/0x30
<4>[ 7290.415697] [<ffffffffa0dd53a1>] ? iwl3945_rx_reply_tx+0xc1/0x450 [iwl3945]
<4>[ 7290.415723] [<ffffffffa0dc8c47>] iwl3945_irq_tasklet+0x657/0x1740 [iwl3945]
<4>[ 7290.415746] [<ffffffff8138fc60>] ? _spin_unlock+0x30/0x60
<4>[ 7290.415764] [<ffffffff81049a21>] tasklet_action+0x101/0x110
<4>[ 7290.415783] [<ffffffff8104a3d0>] __do_softirq+0xc0/0x160
<4>[ 7290.415801] [<ffffffff8100d01c>] call_softirq+0x1c/0x30
<4>[ 7290.415818] [<ffffffff8100eff5>] do_softirq+0x75/0xb0
<4>[ 7290.415835] [<ffffffff81049ee5>] irq_exit+0x95/0xa0
<4>[ 7290.415852] [<ffffffff8100e547>] do_IRQ+0x77/0xf0
<4>[ 7290.415869] [<ffffffff8100c7d3>] ret_from_intr+0x0/0xf
<4>[ 7290.415883] <EOI> [<ffffffff81234efa>] ? acpi_idle_enter_bm+0x270/0x2a5
<4>[ 7290.415911] [<ffffffff81234f04>] ? acpi_idle_enter_bm+0x27a/0x2a5
<4>[ 7290.415931] [<ffffffff81234efa>] ? acpi_idle_enter_bm+0x270/0x2a5
<4>[ 7290.415952] [<ffffffff812c11f3>] ? cpuidle_idle_call+0x93/0xf0
<4>[ 7290.415971] [<ffffffff8100b0d7>] ? cpu_idle+0xa7/0x110
<4>[ 7290.415989] [<ffffffff8137b3d5>] ? rest_init+0x75/0x80
<4>[ 7290.416007] [<ffffffff8158cd0a>] ? start_kernel+0x3a7/0x3b3
<4>[ 7290.416026] [<ffffffff8158c315>] ? x86_64_start_reservations+0x125/0x129
<4>[ 7290.416047] [<ffffffff8158c3fd>] ? x86_64_start_kernel+0xe4/0xeb

Reported-by: Maxim Levitsky <maximlevitsky@xxxxxxxxx>
Tested-by: Maxim Levitsky <maximlevitsky@xxxxxxxxx>
Signed-off-by: Zhu Yi <yi.zhu@xxxxxxxxx>
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/net/wireless/iwlwifi/iwl-dev.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index c2d9b7a..cea2ee2 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -703,7 +703,7 @@ extern void iwl_txq_ctx_stop(struct iwl_priv *priv);
extern int iwl_queue_space(const struct iwl_queue *q);
static inline int iwl_queue_used(const struct iwl_queue *q, int i)
{
- return q->write_ptr > q->read_ptr ?
+ return q->write_ptr >= q->read_ptr ?
(i >= q->read_ptr && i < q->write_ptr) :
!(i < q->read_ptr && i >= q->write_ptr);
}
--
1.6.6

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