On Fri, Jul 31, 2020 at 02:02:55PM -0700, Nick Desaulniers wrote: > From: Pi-Hsun Shih <pihsun@xxxxxxxxxxxx> > > commit 6989310f5d4327e8595664954edd40a7f99ddd0d upstream. > > Use offsetof to calculate offset of a field to take advantage of > compiler built-in version when possible, and avoid UBSAN warning when > compiling with Clang: > > ================================================================== > UBSAN: Undefined behaviour in net/wireless/wext-core.c:525:14 > member access within null pointer of type 'struct iw_point' > CPU: 3 PID: 165 Comm: kworker/u16:3 Tainted: G S W 4.19.23 #43 > Workqueue: cfg80211 __cfg80211_scan_done [cfg80211] > Call trace: > dump_backtrace+0x0/0x194 > show_stack+0x20/0x2c > __dump_stack+0x20/0x28 > dump_stack+0x70/0x94 > ubsan_epilogue+0x14/0x44 > ubsan_type_mismatch_common+0xf4/0xfc > __ubsan_handle_type_mismatch_v1+0x34/0x54 > wireless_send_event+0x3cc/0x470 > ___cfg80211_scan_done+0x13c/0x220 [cfg80211] > __cfg80211_scan_done+0x28/0x34 [cfg80211] > process_one_work+0x170/0x35c > worker_thread+0x254/0x380 > kthread+0x13c/0x158 > ret_from_fork+0x10/0x18 > =================================================================== > > Signed-off-by: Pi-Hsun Shih <pihsun@xxxxxxxxxxxx> > Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > Link: https://lore.kernel.org/r/20191204081307.138765-1-pihsun@xxxxxxxxxxxx > Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > Fix landed in v5.7-rc1. Thanks to James Hsu of MediaTek for the report. What about 5.4.y? Why ignore that tree? You can not have people moving from an older stable to a newer stable tree and have regressions :( I'll queue it up there, but be more careful next time please. greg k-h
