Double free crash is observed when FW recovery(caused by wmi
timeout/crash) is followed by immediate suspend event. The FW recovery
is triggered by ath10k_core_restart() which calls driver clean up via
ath10k_halt(). When the suspend event occurs between the FW recovery,
the restart worker thread is put into frozen state until suspend completes.
The suspend event triggers ath10k_stop() which again triggers ath10k_halt()
The double invocation of ath10k_halt() causes ath10k_htt_rx_free() to be
called twice(Note: ath10k_htt_rx_alloc was not called by restart worker
thread because of its frozen state), causing the crash.
To fix this, during the suspend flow, skip call to ath10k_halt() in
ath10k_stop() when the current driver state is ATH10K_STATE_RESTARTING.
Also, for driver state ATH10K_STATE_RESTARTING, call
ath10k_wait_for_suspend() in ath10k_stop(). This is because call to
ath10k_wait_for_suspend() is skipped later in
[ath10k_halt() > ath10k_core_stop()] for the driver state
ATH10K_STATE_RESTARTING.
The frozen restart worker thread will be cancelled during resume when the
device comes out of suspend.
Below is the crash stack for reference:
[ 428.469167] ------------[ cut here ]------------
[ 428.469180] kernel BUG at mm/slub.c:4150!
[ 428.469193] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[ 428.469219] Workqueue: events_unbound async_run_entry_fn
[ 428.469230] RIP: 0010:kfree+0x319/0x31b
[ 428.469241] RSP: 0018:ffffa1fac015fc30 EFLAGS: 00010246
[ 428.469247] RAX: ffffedb10419d108 RBX: ffff8c05262b0000
[ 428.469252] RDX: ffff8c04a8c07000 RSI: 0000000000000000
[ 428.469256] RBP: ffffa1fac015fc78 R08: 0000000000000000
[ 428.469276] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 428.469285] Call Trace:
[ 428.469295] ? dma_free_attrs+0x5f/0x7d
[ 428.469320] ath10k_core_stop+0x5b/0x6f
[ 428.469336] ath10k_halt+0x126/0x177
[ 428.469352] ath10k_stop+0x41/0x7e
[ 428.469387] drv_stop+0x88/0x10e
[ 428.469410] __ieee80211_suspend+0x297/0x411
[ 428.469441] rdev_suspend+0x6e/0xd0
[ 428.469462] wiphy_suspend+0xb1/0x105
[ 428.469483] ? name_show+0x2d/0x2d
[ 428.469490] dpm_run_callback+0x8c/0x126
[ 428.469511] ? name_show+0x2d/0x2d
[ 428.469517] __device_suspend+0x2e7/0x41b
[ 428.469523] async_suspend+0x1f/0x93
[ 428.469529] async_run_entry_fn+0x3d/0xd1
[ 428.469535] process_one_work+0x1b1/0x329
[ 428.469541] worker_thread+0x213/0x372
[ 428.469547] kthread+0x150/0x15f
[ 428.469552] ? pr_cont_work+0x58/0x58
[ 428.469558] ? kthread_blkcg+0x31/0x31
Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00288-QCARMSWPZ-1
Co-developed-by: Wen Gong <quic_wgong@xxxxxxxxxxx>
Signed-off-by: Wen Gong <quic_wgong@xxxxxxxxxxx>
Signed-off-by: Abhishek Kumar <kuabhs@xxxxxxxxxxxx>
---
Changes in v2:
- Fixed typo, replaced ath11k by ath10k in the comments.
- Adjusted the position of my S-O-B tag.
- Added the Tested-on tag.
drivers/net/wireless/ath/ath10k/mac.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index d804e19a742a..e9c1f11fef0a 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -5345,8 +5345,22 @@ static void ath10k_stop(struct ieee80211_hw *hw)
mutex_lock(&ar->conf_mutex);
if (ar->state != ATH10K_STATE_OFF) {
- if (!ar->hw_rfkill_on)
- ath10k_halt(ar);
+ if (!ar->hw_rfkill_on) {
+ /* If the current driver state is RESTARTING but not yet
+ * fully RESTARTED because of incoming suspend event,
+ * then ath10k_halt is already called via
+ * ath10k_core_restart and should not be called here.
+ */
+ if (ar->state != ATH10K_STATE_RESTARTING)
+ ath10k_halt(ar);
+ else
+ /* Suspending here, because when in RESTARTING
+ * state, ath10k_core_stop skips
+ * ath10k_wait_for_suspend.
+ */
+ ath10k_wait_for_suspend(ar,
+ WMI_PDEV_SUSPEND_AND_DISABLE_INTR);
+ }
ar->state = ATH10K_STATE_OFF;
}
mutex_unlock(&ar->conf_mutex);
--
2.36.0.464.gb9c8b46e94-goog
