From b4bda59b47879cce38a6ec5a01cd3cac702b5331 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 7 Jun 2023 20:10:24 +1000 Subject: [PATCH] powerpc/64s: Fix VAS mm use after free The refcount on mm is dropped before the coprocessor is detached. Reported-by: Sachin Sant Fixes: 7bc6f71bdff5f ("powerpc/vas: Define and use common vas_window struct") Fixes: b22f2d88e435c ("powerpc/pseries/vas: Integrate API with open/close windows") Signed-off-by: Nicholas Piggin Tested-by: Sachin Sant Signed-off-by: Michael Ellerman Link: https://msgid.link/20230607101024.14559-1-npiggin@gmail.com --- arch/powerpc/platforms/powernv/vas-window.c | 2 +- arch/powerpc/platforms/pseries/vas.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c index 0072682531d80..b664838008c12 100644 --- a/arch/powerpc/platforms/powernv/vas-window.c +++ b/arch/powerpc/platforms/powernv/vas-window.c @@ -1310,8 +1310,8 @@ int vas_win_close(struct vas_window *vwin) /* if send window, drop reference to matching receive window */ if (window->tx_win) { if (window->user_win) { - put_vas_user_win_ref(&vwin->task_ref); mm_context_remove_vas_window(vwin->task_ref.mm); + put_vas_user_win_ref(&vwin->task_ref); } put_rx_win(window->rxwin); } diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c index 513180467562b..9a44a98ba3420 100644 --- a/arch/powerpc/platforms/pseries/vas.c +++ b/arch/powerpc/platforms/pseries/vas.c @@ -507,8 +507,8 @@ static int vas_deallocate_window(struct vas_window *vwin) vascaps[win->win_type].nr_open_windows--; mutex_unlock(&vas_pseries_mutex); - put_vas_user_win_ref(&vwin->task_ref); mm_context_remove_vas_window(vwin->task_ref.mm); + put_vas_user_win_ref(&vwin->task_ref); kfree(win); return 0;