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| author | Tom Hughes <tom@compton.nu> | 2012-06-27 18:21:15 +0100 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2012-06-27 14:48:13 -0400 |
| commit | 6bb51c70cabaadddc54a6454844eceba91a56083 (patch) | |
| tree | a4bf608aad527aaa16d76ceac99b293b9cd3b6f5 /drivers/net/wireless/ath/ath9k/recv.c | |
| parent | 4b5ebccc40843104d980f0714bc86bfcd5568941 (diff) | |
| download | lwn-6bb51c70cabaadddc54a6454844eceba91a56083.tar.gz lwn-6bb51c70cabaadddc54a6454844eceba91a56083.zip | |
ath9k: fix panic caused by returning a descriptor we have queued for reuse
Commit 3a2923e83c introduced a bug when a corrupt descriptor
is encountered - although the following descriptor is discarded
and returned to the queue for reuse the associated frame is
also returned for processing. This leads to a panic:
BUG: unable to handle kernel NULL pointer dereference at 000000000000003a
IP: [<ffffffffa02599a5>] ath_rx_tasklet+0x165/0x1b00 [ath9k]
Call Trace:
<IRQ>
[<ffffffff812d7fa0>] ? map_single+0x60/0x60
[<ffffffffa028f044>] ? ath9k_ioread32+0x34/0x90 [ath9k]
[<ffffffffa0292eec>] athk9k_tasklet+0xdc/0x160 [ath9k]
[<ffffffff8105e133>] tasklet_action+0x63/0xd0
[<ffffffff8105dbc0>] __do_softirq+0xc0/0x1e0
[<ffffffff8101a873>] ? native_sched_clock+0x13/0x80
[<ffffffff815f9d5c>] call_softirq+0x1c/0x30
[<ffffffff810151f5>] do_softirq+0x75/0xb0
[<ffffffff8105df95>] irq_exit+0xb5/0xc0
[<ffffffff815fa5b3>] do_IRQ+0x63/0xe0
[<ffffffff815f0cea>] common_interrupt+0x6a/0x6a
<EOI>
[<ffffffff8131840a>] ? intel_idle+0xea/0x150
[<ffffffff813183eb>] ? intel_idle+0xcb/0x150
[<ffffffff814a1db9>] cpuidle_enter+0x19/0x20
[<ffffffff814a23d9>] cpuidle_idle_call+0xa9/0x240
[<ffffffff8101c4bf>] cpu_idle+0xaf/0x120
[<ffffffff815cda8e>] rest_init+0x72/0x74
[<ffffffff81cf4c1a>] start_kernel+0x3b7/0x3c4
[<ffffffff81cf4662>] ? repair_env_string+0x5e/0x5e
[<ffffffff81cf4346>] x86_64_start_reservations+0x131/0x135
[<ffffffff81cf444a>] x86_64_start_kernel+0x100/0x10f
Making sure bf is cleared to NULL in this case restores the
old behaviour.
Signed-off-by: Tom Hughes <tom@compton.nu>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers/net/wireless/ath/ath9k/recv.c')
| -rw-r--r-- | drivers/net/wireless/ath/ath9k/recv.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c index 599667ababee..0735aeb3b26c 100644 --- a/drivers/net/wireless/ath/ath9k/recv.c +++ b/drivers/net/wireless/ath/ath9k/recv.c @@ -695,9 +695,9 @@ static bool ath_edma_get_buffers(struct ath_softc *sc, __skb_unlink(skb, &rx_edma->rx_fifo); list_add_tail(&bf->list, &sc->rx.rxbuf); ath_rx_edma_buf_link(sc, qtype); - } else { - bf = NULL; } + + bf = NULL; } *dest = bf; |