acb31476ad
Currently sta airtime is updated without any lock in case of host based airtime calculation. Which may result in accessing the invalid sta pointer in case of continuous station connect/disconnect. This patch fix the kernel null pointer dereference by updating the station airtime with proper RCU lock in case of host based airtime calculation. Proceeding with the analysis of "ARM Kernel Panic". The APSS crash happened due to OOPS on CPU 0. Crash Signature : Unable to handle kernel NULL pointer dereference at virtual address 00000300 During the crash, PC points to "ieee80211_sta_register_airtime+0x1c/0x448 [mac80211]" LR points to "ath10k_txrx_tx_unref+0x17c/0x364 [ath10k_core]". The Backtrace obtained is as follows: [<bf880238>] (ieee80211_sta_register_airtime [mac80211]) from [<bf945a38>] (ath10k_txrx_tx_unref+0x17c/0x364 [ath10k_core]) [<bf945a38>] (ath10k_txrx_tx_unref [ath10k_core]) from [<bf9428e4>] (ath10k_htt_txrx_compl_task+0xa50/0xfc0 [ath10k_core]) [<bf9428e4>] (ath10k_htt_txrx_compl_task [ath10k_core]) from [<bf9b9bc8>] (ath10k_pci_napi_poll+0x50/0xf8 [ath10k_pci]) [<bf9b9bc8>] (ath10k_pci_napi_poll [ath10k_pci]) from [<c059e3b0>] (net_rx_action+0xac/0x160) [<c059e3b0>] (net_rx_action) from [<c02329a4>] (__do_softirq+0x104/0x294) [<c02329a4>] (__do_softirq) from [<c0232b64>] (run_ksoftirqd+0x30/0x90) [<c0232b64>] (run_ksoftirqd) from [<c024e358>] (smpboot_thread_fn+0x25c/0x274) [<c024e358>] (smpboot_thread_fn) from [<c02482fc>] (kthread+0xd8/0xec) Tested HW: QCA9888 Tested FW: 10.4-3.10-00047 Signed-off-by: Venkateswara Naralasetty <vnaralas@codeaurora.org> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Link: https://lore.kernel.org/r/1585736290-17661-1-git-send-email-vnaralas@codeaurora.org
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.