Messages in this thread | | | Date | Sun, 21 Dec 2014 11:25:16 -0600 | From | Eric Biggers <> | Subject | [BUG] rtl8192se: panic accessing unmapped memory in skb |
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Hi,
I have a RTL8192SE wireless card, attached via PCI. Usually it works with no issues, but I recently had a kernel panic occur in the rtl8192se driver. The kernel version is 3.18. Based on my analysis of the panic dump, the panic was caused by a memory access violation in this block of code in rtl92se_rx_query_desc():
if (stats->decrypted) { hdr = (struct ieee80211_hdr *)(skb->data + stats->rx_drvinfo_size + stats->rx_bufshift);
if ((_ieee80211_is_robust_mgmt_frame(hdr)) && (ieee80211_has_protected(hdr->frame_control))) rx_status->flag &= ~RX_FLAG_DECRYPTED; else rx_status->flag |= RX_FLAG_DECRYPTED; }
Specifically, the violation occurred the first time hdr->frame_control was accessed, as part of _ieee80211_is_robust_mgmt_frame().
The panic occurred when the system was under heavy filesystem load but seemingly is not easily reproducible.
There was recently a NULL check that was removed from this exact place in the code, but it was certainly useless. Instead, what's much more suspect to me is that inside _rtl_pci_rx_interrupt(), there is no error checking of the return value of _rtl_pci_init_one_rxdesc(), which might fail if the skb couldn't be allocated. I am wondering if this could be causing the problem.
Eric
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