linux-kernel - [PATCH 5.1 44/62] dma-buf: Discard old fence_excl on retrying get_fences

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190726152306.587203423@linuxfoundation.org>
Date:   Fri, 26 Jul 2019 17:24:56 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chris Wilson <chris@...is-wilson.co.uk>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Christian König <christian.koenig@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sumit Semwal <sumit.semwal@...aro.org>
Subject: [PATCH 5.1 44/62] dma-buf: Discard old fence_excl on retrying get_fences_rcu for realloc

From: Chris Wilson <chris@...is-wilson.co.uk>

commit f5b07b04e5f090a85d1e96938520f2b2b58e4a8e upstream.

If we have to drop the seqcount & rcu lock to perform a krealloc, we
have to restart the loop. In doing so, be careful not to lose track of
the already acquired exclusive fence.

Fixes: fedf54132d24 ("dma-buf: Restart reservation_object_get_fences_rcu() after writes")
Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@...ll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
Cc: Christian König <christian.koenig@....com>
Cc: Alex Deucher <alexander.deucher@....com>
Cc: Sumit Semwal <sumit.semwal@...aro.org>
Cc: stable@...r.kernel.org #v4.10
Reviewed-by: Christian König <christian.koenig@....com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190604125323.21396-1-chris@chris-wilson.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/dma-buf/reservation.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/dma-buf/reservation.c
+++ b/drivers/dma-buf/reservation.c
@@ -357,6 +357,10 @@ int reservation_object_get_fences_rcu(st
 					   GFP_NOWAIT | __GFP_NOWARN);
 			if (!nshared) {
 				rcu_read_unlock();
+
+				dma_fence_put(fence_excl);
+				fence_excl = NULL;
+
 				nshared = krealloc(shared, sz, GFP_KERNEL);
 				if (nshared) {
 					shared = nshared;