2018-01-19 13:24 GMT+03:00 Kalle Valo <kv...@codeaurora.org>:
> Adding linux-wireless.
>
> For linux-wireless the full report is here:
>
> https://lkml.kernel.org/r/70aa931f-2f02-dd26-c98b-695d1321f...@molgen.mpg.de
>
> Paul Menzel <pmenzel+linux-ath...@molgen.mpg.de> writes:
>
>> I enabled the undefined behavior sanitizer, and built Linus’ master
>> branch under Ubuntu 16.04 with gcc (Ubuntu 5.4.0-6ubuntu1~16.04.5)
>> 5.4.0 20160609.
>
> As you just recently enabled UBSAN I guess I can assume that this isn't
> a new regression but instead the bug is an old issue?
>
> Can you reproduce the problem easily? That would help with testing
> patches.
>
>> ================================================================================
>> [ 960.737730] UBSAN: Undefined behaviour in
>> drivers/net/wireless/ath/ath10k/mac.c:3092:53
>
> This line is from ath10k_update_channel_list():
>
> ch->max_antenna_gain = channel->max_antenna_gain * 2;
>
>> [ 960.737733] signed integer overflow:
>> [ 960.737735] 2147483647 * 2 cannot be represented in type 'int'
>
> 2147483647 is MAX_INT but I can't immeaditely figure out where that's
> coming from. Maybe unitialised stack somewhere?
>
It comes from wiphy_register(), where INT_MAX assigned to channels[i].orig_mag.
See c4a9fafc77a5 ("cfg80211: fix antenna gain handling")
Later ->orig_mag copied into ->max_antenna_gain in resotre_custom_reg_settings()
And finally ath10k_update_channel_list() multiplies ->max_antenna_gain by 2
( since commit 02256930d9b8 ("ath10k: use proper tx power unit") ).
>> [ 960.737738] CPU: 1 PID: 2663 Comm: crda Not tainted 4.15.0-rc6+ #36
>> [ 960.737739] Hardware name: Dell Inc. XPS 13 9360/0839Y6, BIOS 2.4.2
>> 11/21/2017
>> [ 960.737740] Call Trace:
>> [ 960.737749] dump_stack+0x70/0xb2
>> [ 960.737753] ubsan_epilogue+0x9/0x40
>> [ 960.737758] handle_overflow+0xce/0xf0
>> [ 960.737762] ? ecryptfs_decode_and_decrypt_filename+0x104/0x530
>> [ 960.737764] ? __kmalloc+0x265/0x370
>> [ 960.737774] ath10k_regd_update+0x39d/0x5f0 [ath10k_core]
>> [ 960.737782] ath10k_reg_notifier+0x114/0x180 [ath10k_core]
>> [ 960.737802] set_regdom+0x275/0x910 [cfg80211]
>> [ 960.737821] nl80211_set_reg+0x19c/0x630 [cfg80211]
>> [ 960.737826] genl_family_rcv_msg+0x2c4/0x610
>> [ 960.737830] ? radix_tree_next_chunk+0x9f/0x570
>> [ 960.737832] genl_rcv_msg+0x5d/0xe0
>> [ 960.737835] ? __alloc_skb+0x82/0x260
>> [ 960.737838] ? genl_family_rcv_msg+0x610/0x610
>> [ 960.737840] netlink_rcv_skb+0xd5/0x130
>> [ 960.737842] genl_rcv+0x24/0x40
>> [ 960.737844] netlink_unicast+0x1cc/0x300
>> [ 960.737847] netlink_sendmsg+0x29a/0x5f0
>> [ 960.737850] sock_sendmsg+0x4c/0xa0
>> [ 960.737853] ___sys_sendmsg+0x30e/0x440
>> [ 960.737857] ? pagevec_lru_move_fn+0xc3/0x130
>> [ 960.737859] ? trace_event_raw_event_mm_lru_activate+0x100/0x100
>> [ 960.737862] ? __lru_cache_add+0x6a/0xb0
>> [ 960.737865] ? __sys_sendmsg+0x51/0x90
>> [ 960.737868] __sys_sendmsg+0x51/0x90
>> [ 960.737872] entry_SYSCALL_64_fastpath+0x1e/0x81
>
