Messages in this thread | | | Date | Sun, 27 Mar 2022 10:15:30 -0700 | From | Davidlohr Bueso <> | Subject | Re: [PATCH] list: Fix another data-race around ep->rdllist. |
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On Sat, 26 Mar 2022, Kuniyuki Iwashima wrote:
>syzbot had reported another race around ep->rdllist. ep_poll() calls >list_empty_careful() locklessly to check if the list is empty or not >by testing rdllist->prev == rdllist->next. > >When the list does not have any nodes, the next and prev arguments of >__list_add() is the same head pointer. Thus the write to head->prev >there is racy with lockless list_empty_careful() and needs WRITE_ONCE() >to avoid store-tearing. > >Note that the reader side is already fixed in the patch [0]. > >[0]: https://lore.kernel.org/mm-commits/20220326031647.DD24EC004DD@smtp.kernel.org/ > >BUG: KCSAN: data-race in do_epoll_ctl / do_epoll_wait
I think this needs to be part of the same list-fix-a-data-race-around-ep-rdllist.patch
Thanks, Davidlohr
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