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ath10k: perform crash dump collection in workqueue

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Commit 25733c4e67 ("ath10k: pci: use mutex for diagnostic window CE
polling") introduced a regression where we try to sleep (grab a mutex)
in an atomic context:

[  233.602619] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:254
[  233.602626] in_atomic(): 1, irqs_disabled(): 0, pid: 0, name: swapper/0
[  233.602636] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.1.0-rc2 #4
[  233.602642] Hardware name: Google Scarlet (DT)
[  233.602647] Call trace:
[  233.602663]  dump_backtrace+0x0/0x11c
[  233.602672]  show_stack+0x20/0x28
[  233.602681]  dump_stack+0x98/0xbc
[  233.602690]  ___might_sleep+0x154/0x16c
[  233.602696]  __might_sleep+0x78/0x88
[  233.602704]  mutex_lock+0x2c/0x5c
[  233.602717]  ath10k_pci_diag_read_mem+0x68/0x21c [ath10k_pci]
[  233.602725]  ath10k_pci_diag_read32+0x48/0x74 [ath10k_pci]
[  233.602733]  ath10k_pci_dump_registers+0x5c/0x16c [ath10k_pci]
[  233.602741]  ath10k_pci_fw_crashed_dump+0xb8/0x548 [ath10k_pci]
[  233.602749]  ath10k_pci_napi_poll+0x60/0x128 [ath10k_pci]
[  233.602757]  net_rx_action+0x140/0x388
[  233.602766]  __do_softirq+0x1b0/0x35c
[...]

ath10k_pci_fw_crashed_dump() is called from NAPI contexts, and firmware
memory dumps are retrieved using the diag memory interface.

A simple reproduction case is to run this on QCA6174A /
WLAN.RM.4.4.1-00132-QCARMSWP-1, which happens to be a way to b0rk the
firmware:

  dd if=/sys/kernel/debug/ieee80211/phy0/ath10k/mem_value bs=4K count=1
of=/dev/null

(NB: simulated firmware crashes, via debugfs, don't trigger firmware
dumps.)

The fix is to move the crash-dump into a workqueue context, and avoid
relying on 'data_lock' for most mutual exclusion. We only keep using it
here for protecting 'fw_crash_counter', while the rest of the coredump
buffers are protected by a new 'dump_mutex'.

I've tested the above with simulated firmware crashes (debugfs 'reset'
file), real firmware crashes (the 'dd' command above), and a variety of
reboot and suspend/resume configurations on QCA6174A.

Reported here:
http://lkml.kernel.org/linux-wireless/20190325202706.GA68720@google.com

Fixes: 25733c4e67 ("ath10k: pci: use mutex for diagnostic window CE polling")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
This commit is contained in:
Brian Norris
2019-03-26 13:57:28 -07:00
committed by Kalle Valo
parent b82d6c1f8f
commit 38faed1504
6 changed files with 29 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/net/wireless/ath/ath10k/pci.c
View File

@@ -1441,7 +1441,7 @@ static void ath10k_pci_dump_registers(struct ath10k *ar,
__le32 reg_dump_values[REG_DUMP_COUNT_QCA988X] = {};
int i, ret;
lockdep_assert_held(&ar->data_lock);
lockdep_assert_held(&ar->dump_mutex);
ret = ath10k_pci_diag_read_hi(ar, &reg_dump_values[0],
hi_failure_state,
@@ -1656,7 +1656,7 @@ static void ath10k_pci_dump_memory(struct ath10k *ar,
int ret, i;
u8 *buf;
lockdep_assert_held(&ar->data_lock);
lockdep_assert_held(&ar->dump_mutex);
if (!crash_data)
return;
@@ -1734,14 +1734,19 @@ static void ath10k_pci_dump_memory(struct ath10k *ar,
}
}
static void ath10k_pci_fw_crashed_dump(struct ath10k *ar)
static void ath10k_pci_fw_dump_work(struct work_struct *work)
{
struct ath10k_pci *ar_pci = container_of(work, struct ath10k_pci,
dump_work);
struct ath10k_fw_crash_data *crash_data;
struct ath10k *ar = ar_pci->ar;
char guid[UUID_STRING_LEN + 1];
spin_lock_bh(&ar->data_lock);
mutex_lock(&ar->dump_mutex);
spin_lock_bh(&ar->data_lock);
ar->stats.fw_crash_counter++;
spin_unlock_bh(&ar->data_lock);
crash_data = ath10k_coredump_new(ar);
@@ -1756,11 +1761,18 @@ static void ath10k_pci_fw_crashed_dump(struct ath10k *ar)
ath10k_ce_dump_registers(ar, crash_data);
ath10k_pci_dump_memory(ar, crash_data);
spin_unlock_bh(&ar->data_lock);
mutex_unlock(&ar->dump_mutex);
queue_work(ar->workqueue, &ar->restart_work);
}
static void ath10k_pci_fw_crashed_dump(struct ath10k *ar)
{
struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
queue_work(ar->workqueue, &ar_pci->dump_work);
}
void ath10k_pci_hif_send_complete_check(struct ath10k *ar, u8 pipe,
int force)
{
@@ -3442,6 +3454,8 @@ int ath10k_pci_setup_resource(struct ath10k *ar)
spin_lock_init(&ar_pci->ps_lock);
mutex_init(&ar_pci->ce_diag_mutex);
INIT_WORK(&ar_pci->dump_work, ath10k_pci_fw_dump_work);
timer_setup(&ar_pci->rx_post_retry, ath10k_pci_rx_replenish_retry, 0);
if (QCA_REV_6174(ar) || QCA_REV_9377(ar))